· 2017-03-06 · ii Chair of the Conference Prof. Dr. Ahmet TUTAR Co-Chair of the Conference...

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October 26-30 2016 Skopje Macedonia

I I I N T E R N A T I O N A L T U R K I C WO R L DCON F E R E N C E O N C H EM I C A LS C I E N C E S A N D T E C H NO LOG I E S

BOOK OFPROCEEDINGS 2016

ITWCCST

i

T.C SAKARYA UNIVERSITY

FACULTY OF SCIENCEAND ARTS DEPARTMENT OF CHEMISTRY

2nd INTERNATIONAL TURKIC WORLD CONFERANCE ON CHEMICAL SCIENCES AND

TECHNOLOGIES

(2nd ITWCCST)

26th OCTOBER-30th OCTOBER

2016

SKOPJE

MACEDONIA

ii

Chair of the Conference Prof. Dr. Ahmet TUTAR

Co-Chair of the Conference

Prof. Dr. Vullnet AMETI

Congress Secretary Prof. Dr. Ahmet TUTAR

Sakarya University

Research Assist. Yavuz DERİN Sakarya University

Master Student Ömer Faruk TUTAR

Sakarya University

Organization Secretary Musa Köse

Zenith Group D.O.O. Sarajevo, Bosnia and Herzegovina

Hana Sarkinovic Zenith Group D.O.O. Sarajevo, Bosnia and Herzegovina

İsmet Uzun Balkan Research and Development Center / BALDER, Sarajevo, Bosnia and

Herzegovina

iii

Organization Committee Prof. Dr. Ahmet TUTAR Sakarya University Prof. Dr. Prof. Dr. Mehmet Hakkı ALMA Kahramanmaraş Sütçü İmam University Prof. Dr. Mahammed BABANLİ Azerbaijan National Academy of Sciences Assoc. Prof. Dr. Famil VALIYEV SOCAR, Azerbaijan Assist. Prof. Dr. Gulbeniz MUKHTAROVA Enstutite of Petrochemical Processes. Doc. Dr. Shefket DEARİ Tetova State University Dr. Sc. Zulxhevat ABDİU Tetova State University Mr. Sc. Arianit REKA Tetova State University Assoc. Prof. Dr. Hüseyin ALTUNDAĞ Sakarya University Assoc. Prof. Dr. Gülnur ARABACI Sakarya University Assist. Prof. Dr. Kemal KARADENİZ Sakarya University Assist. Prof. Dr. Murat TUNA Sakarya University Assist. Prof. Dr. Esra ALTINTIĞ Sakarya University Research Assist. Yavuz DERİN Sakarya University Raşit Fikret YILMAZ Sakarya University Büşra ALBAYRAK Sakarya University Akın ÖZDEMİR Sakarya University Ömer Faruk TUTAR Sakarya University

Scientific Committee Prof. Dr. Abdolali AlEMİ Tabriz University Prof. Dr. Abdurrahim KOÇYİĞİT Bezmialem Vakıf University Prof. Dr. Abel MAHARRAMOW Bakü State University Prof. Dr. Ahmed KAYACIER Bursa Technical University Prof. Dr. Ahmet DEMİRBAŞ Karadeniz Technical University Prof. Dr. Ahmet SARI Karadeniz Technical University Prof. Dr. Ahmet TUTAR Sakarya University Prof. Dr. Prof. Dr. Akif AZİZOV Azerbaijan National Academy of Sciences Prof. Dr. Bagher EFTEKHARI-SIS University of Maragheh Prof. Dr. Bilal ACEMİOĞLU Kilis 7 Aralık University Prof. Dr. Bolat URALBEKOV El-Farabi Kazak National University Prof. Dr. Dilek ŞOLPAN ÖZBAY Hacettepe University Prof. Dr. Dilgam TAGİYEV Azerbaijan National Academy of Sciences Prof. Dr. Emine SALAMCI Atatürk University Prof. Dr. Erdoğan KÜÇÜKÖNER Süleyman Demirel University Prof. Dr. Esvet AKBAŞ Yüzüncü Yıl University Prof. Dr. Fatih SATIL Balıkesir University Prof. Dr. Farid YAMBUŞEV Kazan Federal University Prof. Dr. Farida KARATAEVA Kazan Federal University Prof. Dr. Florida KUDASHEVA Bashkir Government University Prof. Dr. Hacali NECEFOĞLU Kafkas University Prof. Dr. Harun PARLAR Munich University Prof. Dr. Hüseyin KARA Selçuk University Prof. Dr. İlyas NİZAMOV Kazan Federal University Tatarstan Prof. Dr. İsmet KAYA Çanakkale Onsekiz Mart University Prof. Dr. İsmail USTA Marmara University

vi

Prof. Dr. Mahammed BABANLY Azerbaijan National Academy of Sciences Prof. Dr. Mehmet AKALIN Marmara University Prof. Dr. Mehmet Hakkı ALMA Kahramanmaraş Sütçü İmam University Prof. Dr. Mehmet SÖNMEZ Gaziantep University Prof. Dr. Metin BÜLBÜL Dumlupınar University Prof. Dr. Mohammed Taghi ZAFARANİ-MOATTAR Tabriz University Prof. Dr. Muhammet ARİCİ Yıldız Technical University Prof. Dr. Murat TEKER Sakarya University Prof. Dr. Mustafa SOYLAK Erciyes University Prof. Dr. Nurettin YAYLI Karadeniz Technical University Prof. Dr. Osman SAĞDIÇ Yıldız Technical University Prof. Dr. Ömer IŞILDAK Gaziosmanpaşa University Prof. Dr. Rinat AKHMETKHANOV Bashkir University Prof. Dr. Rustem AMİROV Kazan Federal University Prof. Dr. Sharipa JOROBEKOVA Kirgizsan National Sciences Academia Prof. Dr. Sluken RAKHMADİEVA L.N. Gumilev Eurasia National University Prof. Dr. Tofik NAGİYEV Azerbaijan National Academy of Sciences Prof. Dr. Ümit SALAN Marmara University Prof. Dr. Vagif ABBASOV Azerbaijan National Academy of Sciences Prof. Dr. Vagif FARZALİYEV Azerbaijan National Academy of Sciences Prof. Dr. Yavuz ONGANER Atatürk University Prof. Dr. Yerdos ONGARBAYEV El-Farabi Kazak National University Prof. Dr. Yücel KADIOĞLU Erzincan University Prof. Dr. Xhezair IDRIZI Tetova State University Doc. Dr. Ahmed JASHARİ Tetova State University Doc. Dr. Luljeta RAKA Tetova State University Doc. Dr. Teuta Gjuladin-HELLON Tetova State University

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Dear Participants;

The Second International Turkic World Conference on Chemical Sciences and Technologies organized by collaboration of Sakarya University Faculty of Arts and Science Chemistry Department and Kahraman Maraş Sütçü İmam University and hosted by Tetova State. We are happy that the conference was held in such a beatiful city and wonderful country to which we have many historical relations.

Chemistry is a central science, because a basic knowledge chemistry is essential for healt, agriculture, engineering and natural sciences. The technological and scientific developments eliminate the sharp lines among the brances of science. Any new development in science will affect the whole science world and we believe that chemistry has a privilege among them. Thus, chemistry has broader applications and intersects with many other of them.

We are happy to see that the conference held last year in Sarajevo enabled many scientists to form good relationships that resulted in new projects. We wish that this conferance opens new doors to new projects and new relations as in last year. In this respect, we desired that the scienctists in Turkic world come here, meet and creat new projects together.

The scientist attended the conference was from 15 diffent contriy and mostly from Turkey and Azerbaijan. Total 381 scientist, educater, industrialist and from other fields were registrated in the conference. The total number of submission were 404 and after a careful evaluation 315 submissions were accepted by our scientific committee and 146 of them were accepted as oral presentation and 169 of them were accepted as poster presentation and abstract part of all those presentation was taken place in the conference booklet.

We would like to thank to Rector of Sakarya University Prof. Dr. Muzaffer ELMAS for giving us permission and also supporting us both financially and morally and also we thank to the Dean of Faculty of Arts and Science of Sakarya University Prof. Dr. Yılmaz DAŞÇIOĞLU. And the most importantly I would like to thank to all the participants individually who came from away to join this conference.

Prof. Dr. Ahmet TUTAR

2nd ITWCCST – October 26-30, 2016 - Skopje, Macedonia.

CONTENT FOREWORD vii CONTENT viii The Effect of Humic Acid Extracted by Wet-Alkali Technique and Interacted by N2/O2 Gases in Alkali Condition on the Contents of Macro Nutrients in Corn Ayhan HORUZ, Mümin DİZMAN, Ahmet TUTAR

1

Application of GIS In A Physical Land Evaluation Suitability For Field Crops (Wheat & Barley) Orhan DENGIZ, Ayhan HORUZ

10

The Effect of the Rates of Different Organic Fertilizers on Restoring Productivity of Eroded Soils Nutullah ÖZDEMİR, Tugrul YAKUPOĞLU, Ayhan HORUZ

16

The Enhancement effect of Cetyltrimethylammonium Bromide in the Electrochemical Response of Carbon Paste Electrode to Nitrophenols Arsim MALOKU, Liridon S. BERISHA, Granit JASHARI, Eduard ANDONI, Tahir ARBNESHI

20

A Comparative Study on Enzymatically and Chemically Synthesized Maleic anhydride-Styrene Copolymer Ersen YILMAZ

24

Kinetics of Zn (II) Ions Adsorption onto Chitin Nilüfer Nacar Koçer, Gülşad Uslu, Arzu Y. DURSUN, and Barbaros DURMUŞ

27

Removal of Zn (II) Ions from Aqueous Solution by Chitin Arzu Y. DURSUN, Nilüfer NACAR KOÇER, Gülşad USLU, Neslihan ÇANAKÇI

DURMUŞ 31

Estimation of Blast for VCE: A Case Study Merve Ercan KALKAN, Dicle ÇELİK, Kadriye OKTOR 35

First-principles Study of Electronic and Dynamic Properties of Co3V Compound Nihat ARIKAN 39

Use of Chitosan in the Polymer Composites as an Antibacterial Material Hüsnügül YILMAZ ATAY 47

Density Functional Study of the Structural and Electronic Properties of Ir2ScBi Nihat ARIKAN

51

Hydrothermal Reaction of Trepel with Ca(OH)2 Arianit A. REKA, Blagoj PAVLOVSKI, Njomza BUXHAKU, Bujar DURMISHI, Ahmed JASHARI, Shefket DEHARI, Kiril LISICKOV

54

Antioxidative Properties of a Special Traditional Food Plant Roots: Urtica Urens Emine BAĞDATLI, Aliye GEDIZ ERTURK,

Melek GÜL 59

Structural, Electronic, Elastic and Vibrational Properties of Spinel MgIn2O4 and ZnIn2O4: A First-principles Study Ahmet İYİGÖR, Mustafa ÖZDURAN, Abdullah CANDAN

62

First-Principle Study of the Structural and Mechanical Properties of RuTi Compound Osman ÖRNEK 66

Synthesis and Characterization of p-Chlorobenzoylthiourea Amino Acid Derivatives RamizahRAMLI, SitiKamilah CHE SOH, NurzianaNGAH, M. Sukeri M. YUSOF 69

Structural, Elastic and Electronic Properties of Fe2TiSi Full-Heusler Compound Mustafa ÖZDURAN, Raşit UMUCU

73

First Principles Calculation of Ru2VGa and Ru2CrGa Heusler Alloys Ahmet İYİGÖR, Abdullah CANDAN, Mustafa ÖZDURAN

76

2nd ITWCCST – October 26-30, 2016 - Skopje, Macedonia.

Determination of The Time-Independent Rheological Behavior of Peanut Butter and Its Modeling Hakan YOĞURTÇU

80

Stability and Durability of Polyvinyl Chloride Membranes Consisting of Aliquat 336 Yasemin YILDIZ, Aynur MANZAK

84

Optimization of Digestion Procedures for the Determination of Lead and Cadmium in Mussel Samples Mustafa TÜZEN

88

Atomic Absorption Spectrometric Determination of Some Heavy Metal Ions in Boiled Grape Juice Samples Mustafa TÜZEN

91

Influence of Aluminium Introduced into Natural Zeolites on Arsenic Removal from Aqueous Medium Ayten ATEŞ

94

Photobromination of Monobromoindanones and Efficient Synthesis of 5-bromo-2,2 dimethoxyindan-1,3-dione İbrahim Halil BAYDİLEK, Raşit Fikret YILMAZ, Yavuz DERİN, Ömer Faruk

TUTAR, Ahmet TUTAR 99

A Study on Thermodynamical Proporties Of Melatonin in Blood by Using DFT and HF Faik GÖKALP 102

The Investigation of Dyeing Kinetics of Polyamide Fiber with Acid Dyes under The Microwave Conditions Murat TEKER, Hilal G. TEKER ALŞAN, Hatice ÖKER

108

Bentonite/Capric Acid Composite PCMs: Preparation, Characterization and Latent Heat Thermal Energy Storage Characteristics Ahmet SARI

113

Latent Heat Thermal Energy Storage by Using Phase Change Materials Ahmet SARI

116

Microencapsulated Phase Change Materials (MEPCMs) for Latent Heat Thermal Energy Storage Ahmet SARI

120

Antioxidant Activity of Caffeic Acid Isolated from Origanum bilgeri P.H. Davis Ramazan ERENLER, Gulacti TOPCU

123

The Investigation of Dyeing Kinetics of Cotton Fibers With Reactive Dye in The Microwave Media Murat TEKER, Hüseyin KARACA, Zeynep DOYURAN

125

Synthesis of 2-Arylpyrroles by Suzuki-Miyaura Cross-Coupling Reaction Yavuz DERİN, İbrahim Halil BAYDİLEK, Raşit Fikret YILMAZ, Büşra

ALBAYRAK, Salih ÖKTEN, Ahmet TUTAR 129

Removal of C.I. Basic Blue 3 Dyestuff from Textile Waste Waters by Electrochemical Treatment Emrah BULUT

131

Structural Mechanical and Electronic Properties of FeTiSi Raşit UMUCU, Mustafa ÖZDURAN

136

1 2nd ITWCCST – October 26-30, 2016 - Skopje, Macedonia.

The Effect of Humic Acid Extracted by Wet-Alkali Technique and Interacted by N2/O2 Gases in Alkali Condition on the Contents of

Macro Nutrients in Corn

Ayhan HORUZa*, Mümin DİZMANb, Ahmet TUTARc

aOndokuz Mayıs University, Department of Soil Science and Pland Nutrition, 55139 Samsun, Turkey

bYeditepe University, Department of Biotechnology, 34755 Istanbul, Turkey cSakarya University, Department of Chemistry, 54500 Sakarya, Turkey

*e-mail corresponding author:[email protected]

Abstract Humic acid (HA) promote transferring of plant nutrients that can not be uptake in the soil by making chelates. In this study, the effect of humic acid extracted by wet-alkali technique and interacted by N2/O2gases in the alkali condition was investigated on the macronutrients contents in the stalk of corn (Zea mays L.) at the fertilized and unfertilized conditions. In the experiment, two different humic acids were applied separately to the soil at the doses of 0, 100, 200, 400 and 800 ppm in the 2x5 factorial designs with three repetitions before planting corn. According to the variance analysis, it was found that humic acid doses increase significantly the contents of corn nutrients compared to control except for phosphorus (P) in unfertilizer condition. This increase was found significant at 1% level of Mg in unfertilized condition and at 5% level of P and sulphate (SO4) in fertilizer condition according to the type HA. It was found significant the effect of humic acid x dose interction on the corn magnesium (Mg) and SO4 contents in the unfertilized conditions, while it was important P and Mg contents in fertilized conditions. The highest nutrient element contents obtained from unfertilized condition were found as 2,19% nitrogen (N), 0,110% P, 1,484% calcium (Ca) and 0,165% SO4, in 800 ppm of HA interacted by N2/O2gases and 0,148% Mg in 200 ppm HA dose. In 400 ppm dose of wet-alkali extracted HA obtained as 2,11% potassium (K). The highest nutrient element contents obtained from fertilized condition was found as 2,04% N, 0,476% P, 0,336% SO4 in 800 ppm dose of HA interacted by N2/O2gases and 3,36% K in 400 ppm HA dose. In 200 and 400 ppm doses of wet-alkali extracted HA obtained as 1,41% Ca and 0,569%. According to the results, it was determined that both wet-alkali extracted HA and interacted by N2/O2gases in both condition generally increased the nutrient contents of corn, but there was no difference between humic acid varieties. It was found to be more effective the use of fertilized condition than unfertilized one.

Key words: Humic acid, Wet alkali technique, Interacted by N2/O2 gases, Corn, Macro nutrients

INTRODUCTION

Humic substances (HS) play a vital role in soil

fertility and plant nutrition. Theyare also considered as a key component of sustainable agricultural practices and soil and plant ecosystems since they are responsible for many complex chemical reactions in soil (Stevenson, 1994). In soil, one of the most important characteristics of HS is their ability to interact with metal ions, oxides, hydroxides, mineral and organic compounds, (Yamauchi et al., 1984).Compounds from all the mentioned groups will have one or more active functional chemical groups like carboxylic acid (COOH), hydroxyl (-OH), carbonyl (C=O), phenolic

rings and quinone groups that can and will react to charged positive or negative ions in solution. The presence of functional groups like carboxylic and phenol groups allows humic and fulvic acids to form complexes with ions such as HPO4

2-, K+, Mg2+, Ca2+. Usually humic and fulvic acids have two or more of these groups arranged as to enable the formation of chelate complexes (Vermeer, 1996; Turan and Horuz 2012). It can then only assist in enhancing the uptake and utilization of nutrient minerals from the soil by binding the charged minerals on its ion exchange sites and prevent it from reacting with phosphate anions


(Ca2+, Mg2+,) to form insoluble phosphate compounds or with sulphate anions to form poorly soluble gypsum (CaSO4) (Vermeer, 1996). It does however contribute towards cation exchange capacity (CEC) in the soil at sufficient concentrations.

Lee et al. (2005) reported that ozonation has

been used in advanced water treatment processes to minimize the formation of trihalomethanes and to decompose NOM (natural organic matter) in all raw surface waters for drinking water (Amy et al., 1991; Shukairy and Summers, 1992; Kong et al., 2003).

The interaction of HS with plant essential

elements, including N, P, K and micronutrients, is known to improve nutrient availability and also contributes to growth promotion by HS at low rates. This alone creates a substantial agronomic opportunity to improve the efficiency of fertilizer nutrient use over and above enhancing growth alone.

Lime dissolved in neutral or acidic soils, but does not readily disolved in alkaline soil and instead serves as a sink for surface-adsorbed calcium phosphate precipitation (Hopkins and Ellsworh, 2005). Moorover, high pH decreases the availability of P administered as low organic matter chemical fertilizer. Humic acids were added to an alkaline soil with phosphate fertilizer to wheat grown in field trials. It was observed that phosphate uptake and yield were increased by 25% (Wang, 1995).

Several researchers, David (1991), Padem (1999) ,Neri (2002) and El-Desuki (2004) concluded that humic acid as foliar sprays enhanced growth nutrient uptake and yield and improved the quality of the production of some crops, this may be decrease the N,P,K applied as soil application which decrease pollution and costs. humic acid was in general beneficial to shoot and root growth of corn plants. In addition, the presence of humic molecules raised the effect on plants of the fertilization based on N, phosphorus and potassium (Pollhamer, 1993).

In this study, it was to determine the effects of two humic acids (wet alkali extracted and interacted by N2/O2gases) and the most appropriate application of humic acid for macro nutrient contents (N, P, K, Ca, Mg and SO4) of corn grown in the unferilized and fertilized conditions.

MATERIALS AND METHODS

The torf material using to obtaine humic acids was taken from arifiye torf that is one of the potential peat bedding belonging to Sakarya city in the northwest of Turkey. Humic acids was obtained from the activated

torf material with wet alkali extraction and interacted by N2/O2gases methods. The reactive operation was fulfilled with saturation of N2 and O2gases in 150-250°C in otoklav pressure 4 bar (Butuzova et al., 1998). Soil sample for pot experiment was taken from Kurupelit area of Samsun city. The trial carry out as three replications in randomized block design as unfertilized and fertilized conditions in greenhouse of 19 Mayis University Agriculture Faculty Farm in 2013. Unfertilized condition was only test soil no any additional nutrient elements. Fertilized condition was applied as 200 ppm N (ürea 46% N), 80 ppm P (triple superphosphate 42%P2O5), 50 ppm K (K2SO4, 50% K2O), 60 ppm Mg (MgSO4.5H2O), 20 ppm Fe (FeSO4.7H2O), 15 ppm Mn (MnSO4.2H2O), 10 ppm Zn (ZnSO4.7H2O), 5 ppm Cu (CuSO4.5H2O) and 0,5 ppm B (H3BO3) to the per pot during development period. While all micro elements, whole phosphate and one half of nitrogen (100 ppm N) was given together with sowing, second half of nitrogen (100 ppm N) was given after three weeks from planting. Sakarya F1 corn seed was sown 5 number to the per pots on 20.05.2013. After planting left 3 plant. The pots was tried to kept in field capacity during the growing season. Corn harvested by cutting from soil surface after 75 days dvelopment period from planting on 05.08.2013. Plant samples was ready for analysis by grinding in steel grinder after dried in 65°C stove (Kacar, 1984).

Dried samples (500 mg) were digested in 10 ml concentrated HNO3 at 200 °C for 4 h in accordance with the method of Kacar and Katkat (2009). The P concentration in the digest was measured using a JENWAY 6320D Model spectrophotometer. The colorimetric method of Kacar and Katkat (2009).

Nitrogen in plant samples was made by micro kjeldahl method; other plant analysis was made after digestion with 4:1 HNO3:HCIO4 acid mixed; phopsphorus concentration in digest made by spectrophotometer (Janway 6320D) according to the bartın method. K, Ca, Mg and SO4 by Atomic Absorption Spectrophotometer (Perkin Elmer AA-200) was made (Kacar and İnal, 2008).

The change (increase or decrease) in oat plant with silicon fertilization when compared with the control was calculated as follows:

In soil samples, pH and EC were measured in

1:2.5 water extract (Soil Survey Laboratory, 1992). Texture was made by bouyoucos hidrometre method (Bouyouos, 1951). Lime was determined with


calcimeter method (Soil Survey Staff, 1993). Organic matter content was analyzed according to the modified Walkley-Black method (Nelson Sommers 1982). Available P was determined with Shimadzu UV 1208 model spectrophotometer according to Watanabe and Olsen (1965). Exchangeable cations (Na, K, Ca and

Mg) were extracted with ammonium acetate at pH 7.0 (Kacar, 2009), and available Fe, Cu, Zn, Mn were extracted with DTPA (0.005M DTPA + 0.01M CaCl2 + 0.1M TEA pH 7.3) (Lindsay and Norwell 1978) and determined using Perkin Elmer AA-200 model Atomic Absorption Spectrophotometer. Some chemical and physical properties of the soil used in the research are shown in Table 1.

Tablo 1. Some physio-chemical properties of experimental soil

Soil properties Nutrient contents pH 7,89 Total N, % 0,025 EC, % 0,04 P2O5, kg/da 0,39 Lime, % 8,79 K2O, kg/da 80,00 OM, % 1,75 Fe, ppm 16,03 Sand,% 26,24 Mn, ppm 5,93 Mil,% 18,06 Zn, ppm 0,21 Clay,% 55,70 Cu, ppm 2,18 Texture class Clay B, ppm 0,47

Statistical analyses

The experimental design was a completely randomized factorial design with three replicates and obtained data were analyzed by ANOVA. The differences were compared by Duncan’s multiple-range test (α:0.05). The levels of significance are represented by * at P< 0.05, ** at P< 0.01, and ns: non-significant (SPSS 17.0).

RESULTS AND DISCUSSION

The effect of humic acids wet-alkali extracted and

interacted by N2/O2gasesin fertilized and unfertilized conditions on some of the stem+leaf nutrient element content of corn was given in Table 2. According to variance analysis results, humic acid type was found to be statistically significant P and SO4 content in unfertilized conditions and Mg content in fertilized conditions (P<0.05). Humic acid (HA) dose was found to be statistically significant in all applications except phosphor in unfertilized conditions. Humic acid type and HA dose interaction was found statistically significant at 1% level Mg and SO4 contents in unfertilized conditions, at 1% level significant within P content in fertilized conditions and at 5% level significant Mg content in fertilized conditions. İn

fertilized and unfertilized conditions, increasing doses of two humic acid types wet alkaline technique and interacted by N2/O2gases increased nitrogen (N), P, K, Ca, Mg and SO4 contents of corn when compared with the control. Liu (1998) stated that foliar application of 0,1% HA doses in most plants and Çimrin et al. (2001) stated that soil application of 1000 mg kg-1 HA

application in corn significantly increased N, P, K, Ca, Mg contents when compared with the control.

Nitrogen

There was no statistically difference between humic acid types (wet alkali extraction and interacted by N2/O2 gases methods). Humic acid doses increased statistically significant (P<0,01) N content of corn plant in fertilized

conditions and increased significantly (P<0,05) in unfertilized conditions as compared to the control. The highest N content was found as 2,03% at 800 ppm HA dose produced with wet alkaline technique in unfertilized conditions, while it was found as 1,95% at 400 ppm dose in fertilized conditions. HA interacted by N2/O2 gases in fertilized and unfertilized conditions were found as 2,19% and 2,04% at 800 ppm dose, respectively (Table 2). İn both fertilized and unfertilized

conditions, humic acid by producing interacted by N2/O2 gases was found more increase the N content of corn plant than produced with wet alkaline technique. In addition, both humic acids applied in unfertilized conditions were found more increase the N content of corn plant when compared with unfertilized conditions. This may have been caused by more plant development as a result of the existing nitrogen having been used in plant metabolism in fertilized conditions, and thus causing dilution effect of nitrogen in plant. Nitrogen applications up to 100 mg N/kg soil on the sugar beet grew did not affect the total-N content of plants due to nitrogen diluted in yield (İnal and Güneş, 1995). The

highest change as compared to the control was found as 20,29% and 16,79% at 800 ppm dose of humic acid interacted by N2/O2gases applied in both fertilized and unfertilized conditions (Table 3; Figure 1 and 2). Sharif et al (2002) stated that humic acid increased the nitrogen uptake of corn plant, while Nikbakht et al. (2008) stated that humic acid applications increased the nitrogen content of gerbera leaves 40% when compared with the control.

Phosphorus Humic acid dose increased the P content of corn

plant significantly (P<0,05) in fertilized conditions as compared to the control. İn unfertilized conditions, HA interacted by N2/O2gases was found to be statistically significant (P<0,05). The highest P was found as 0,099% at 800 ppm of HA produced with wet alkaline technique in unfertilized conditions, while it was found


as 0,459% at 200 ppm of HA in fertilized conditions; in fertilized and unfertilized conditions, it was found as 0,110% and 0,476%, respectively at 800 ppm of HA interacted by N2/O2gases (Table 2).

HA applied in unfertilized conditions increased the P content of corn plant only at 800 ppm dose and decreased at other HA doses. Sharif et al. (2002) reported that soil P concentration improved significantly

by the addition of 200 mg kg−1 HA whereas plant P accumulation was not significantly affected by the application of different levels of HA. İn fertilized conditions, humic acid that increased in both humic acid types formed a chelat effect with phosphorus and increased uptake by the plant. Pettit (2004) informed that when adequate humic substancesare present within the soil, the requirement for N, P and K fertilizer may be reduced. Humic substances in interaction with phosphorus in the soil candecrease the P fixation and increase the phosphorus uptake of plant (Hua et al., 2008). The highest change as compared to the control was 16,11% and 96,81% at 800 ppm dose of humic acid interacted by N2/O2gasesin both unfertilized and fertilized conditions (Table 3; Figure 1 and 2). P content of corn plant increased 6 times more in fertilized conditions when compared with unfertilized conditions. In addition, it was found that humic acid activated with N2/O2gasesin unfertilized conditions increased the P content of corn plant more when compared with humic acid obtained with wet alkaline technique.Phosphorus decreases the availability of the plant by being fixed to the soil (Wang, 1995; Kacar and Katkat, 2009). Erdal et al. (2000) reported that the dry weight, plant P concentration, P uptake and residual available P amount increased with humic acid applications, and that the effect of humic acid on the above parameters combined with P fertilization was higher than that of humic acid alone. It was stated that in calcareous soils, organic matter competes with P on adsorption surfaces of CaCO3 and weakens the binding energy of P to lime (Halford and Mattingly, 1975). Organic compounds such as humic acid both prevent fixation and promote uptake by the plant by forming a complex with phosphorus (Rubinchik et al. 1992; Kacar and Katkat, 2009; Turan and Horuz, 2012).

Potassium

Humic acid increased the K content of corn plant significantly in both fertilized and unfertilized conditions as compared to the control (P<0,05). No statistically significant difference was found between humic acid types. The highest K content was found as 2,11% at 800 ppm dose of HA produced by unfertilized

wet alkaline technique, as 3,19% at 200 ppm dose of HA produced by fertilized wet alkaline technique while humic acid interacted by N2/O2gasesin fertilized and unfertilized conditions was found as 2,03% at 800 ppm dose and as 3,36% at 400 ppm dose (Table 2). Potassium increases the uptake by the plant by forming K-humate complex with humic acid (Khaled and Fawy, 20011). K content was found to decrease at 800 ppm of humic acid. Defline et al. (2005) reported that humic

acids were applied by spray during the growth season of cultivated crops at a dose of 20 mg/l and the yields of the cultivated crops were not affected significantly by the application of potassium humate due to the high amounts of humic substances. Humic acid applied in fertilized conditions were found to increase the K content of corn plant more when compared with unfertilized conditions. The highest change as compared to the control was found as 19,85% at 400 ppm dose of wet alkali extraction humic acid in unfertilized conditions and as 22,63% at 400 ppm dose of humic acid interacted by N2/O2gasesin fertilized conditions (Table 3; Figure 1 and 2). Fernandez et al. (1996) reported that humic acid applications increased the K content of olive plant leaves. Alak and Müftüoğlu (2014) reported that although humic acid applied at 0, 2, 4, 6, 8 and 10 L did not influence the leaf and stem K content of corn plant statistically, it caused an increase.

Calcium

Humic acid increased the Ca content of corn plant significantly as compared to the control in both fertilized and unfertilized conditions (P<0,05). Dursun et al. (1995) reported that humic acid applications from leaves statistically significantly affected the calcium content of tomato plant. In addition, they found that the humic acid applied on tomato and eggplant seedlings increased the calcium uptake of humic acid when compared with the control. However, no statistical difference was found between humic acid types. The highest Ca content was found as 1,425% at 400 ppm dose of unfertilized wet alkaline technique HA and as 1,83% at 200 ppm of fertilized wet alkaline technique HA, while it was found as 1,484% at 800 ppm dose and as 1,72% at 400 ppm dose of humic acid interacted by fertilized and unfertilized N2/O2 gases (Table 2).

The highest change as compared to the control was found as 64,13% at 800 ppm dose of humic acid interacted by unfertilized N2/O2 gases and as 42,42% at 200 ppm dose of normal humic acid in fertilized conditions (Table 3; Figure 1 and 2). Decreases were found in Ca content of corn plant in humic acid doses except for HA interacted by N2/O2 gases in unfertilized


conditions. Calcium accumulation on the leaves decrease since humic acid-calcium flocculation occurs as a result of high dose humic acid applications (Grossl and Inskeep 1991). Humic acid applied in unfertilized conditions was found more decrease the Ca content of corn plant due to antagonism effects. The reason for this may be the antagonistic association between Ca and nutrient elements applied in fertilized conditions such as P, K, Mg (Aktaş, 1994; Kacar and Katkat, 2009).

Çimrin et al (2001) reported that when only humic acid

was applied, K, Ca and Mg contents of corn plant were significantly decreased.

Magnesium

Humic acid produced with wet alkaline technique and interacted by N2/O2 gases in fertilized conditions was found statistically significant (P<0,05). Humic acid doses increased the Mg content of corn plant significantly as compared to the control in both fertilized and unfertilized conditions (P<0,05).The highest Mg content was found as 0,161% at 200 ppm HA dose of unfertilized wet alkaline technique and as 0,148% at 200 ppm dose of HA interacted by N2/O2 gases in unfertilized condition, while it was found as 0,569% and 0,561% at 400 ppm dose of


Table 2. Some macro nutrient contents of corn (stalk+leaf) in relation to the humic acid Applications

HA

Treatments Doses ppm

N, % P, % K, % Ca, % Mg, % SO4, % -Fert.+ +Fert. -Fert. +Fert. -Fert. +Fert. -Fert. +Fert. -Fert. +Fert. -Fert. +Fert.

Wet-alkali extraction

0 1,82 1,75 0,095 0,242e 1,76 2,74 0,904 1,66 0,129bcd 0,324c 0,122de 0,232 100 1,78 1,85 0,090 0,329d 1,82 2,93 0,952 1,61 0,161a 0,516a 0,144abcd 0,252 200 1,87 1,92 0,092 0,459ab 1,91 3,19 1,060 1,83 0,147abc 0,327c 0,157ab 0,251 400 1,95 1,95 0,094 0,409bc 2,11 3,15 1,425 1,58 0,135bc 0,569a 0,144abcd 0,229 800 2,03 1,88 0,099 0,441abc 1,90 3,15 1,367 1,39 0,125cd 0,521a 0,151abc 0,322

interacted by

N2/O2 gases

0 1,82 1,75 0,095 0,242e 1,76 2,74 0,904 1,66 0,129bcd 0,324c 0,122de 0,232 100 1,59 1,88 0,100 0,393c 1,90 2,87 0,969 1,72 0,108d 0,266c 0,101e 0,270 200 1,90 2,00 0,103 0,412bc 1,93 3,20 1,071 1,59 0,148ab 0,407b 0,133cd 0,263 400 2,11 1,92 0,095 0,434abc 2,00 3,36 1,455 1,53 0,145abc 0,561a 0,137bcd 0,267 800 2,19 2,04 0,110 0,476a 2,03 3,24 1,484 1,40 0,128bcd 0,523a 0,165a 0,336

HA doses

0 CD B - D B B C A B D C B 100 D B - C AB B BC A AB C C B 200 BC A - AB AB A B A A C AB B 400 AB A - B A A A B AB A C B 800 A A - A A A A B B B A A

P: HA types ns ns * ns ns ns ns ns ns * * ns P: Doses ** * ns * * * * * * * ** * P: HA types X doses ns ns ns ** ns ns ns ns ** * ** ns

+: The difference between the mean values shown by apart letters at the same column is statistically important (P≤ 0.05). Fert.: Fertilizer, *:%1 **:%5 ns:Not significant

Table 3. Change of macro nutrient contents of corn stalk in relation to the humic acid applications

Change of macro nutrients, % HA

Treatments Doses ppm

N P K Ca Mg SO4 -Fert.+ +Fert. -Fert. +Fert. -Fert. +Fert. -Fert. +Fert. -Fert. +Fert. -Fert. +Fert.

Wet-alkali extraction

100 -2,19 5,73 -4,95 36,12 3,40 6,81 5,34 12,45 24,81 59,50 17,74 8,35 200 2,74 9,92 -3,47 89,90 8,51 16,42 17,29 42,42 13,72 0,93 28,62 8,05 400 6,77 11,64 -1,05 69,09 19,85 14,96 57,63 33,00 4,88 75,78 17,50 -1,29 800 11,34 7,63 3,89 82,46 7,75 14,84 51,25 -16,84 -3,10 61,04 23,47 38,48

interaced by N2/O2 gases

100 -12,80 7,44 5,26 62,72 7,75 4,62 7,22 -5,38 -16,28 -17,92 -17,42 16,10 200 4,21 14,69 8,74 70,46 9,64 16,79 18,47 16,84 14,50 25,83 8,50 13,34 400 15,54 10,11 0,00 79,56 13,24 22,63 60,98 36,36 12,17 73,40 12,02 14,94 800 20,29 16,79 16,11 96,81 15,13 18,13 64,13 -6,06 -0,78 61,57 35,16 44,51


Figure 1. Change of macro nutrients at wet-alkali extracted HA

Figure 2. Change of macro nutrients at HA extracted by N2/O2 gaseses

-20

0

20

40

60

80

100

unfert. fert. unfert. fert. unfert. fert. unfert. fert. unfert. fert. unfert. fert.

N P K Ca Mg SO4

Rat

e of

cha

nge,

%

Macro nutrients at wet-alkali extracted HA

100 200 400 800

-20

0

20

40

60

80

100

unfer . fer. unfer fer unfer fer unfer fer unfer fer unfer fer

N P K Ca Mg SO4

Rat

e of

cha

nge,

%

Macro nutrients at HA extracted by N2/O2 gases

100 200 400 800


HA produced with wet alkaline technique and interacted 3).The highest change as compared to the control was 24,81% at 100 ppm dose of wet alkaline technique HA in unfertilized conditions and 75,78% at 400 ppm in fertilized conditions (Table 3; Figure 1 and 2). Humic acid applied in fertilized conditions increased the Mg content of corn plant more than unfertilized conditions. Katkat et al. (2009) reported that humic acid applications from the leaves increased the magnesium uptake of wheat plant. El-Nemr et al. (2012) reported that humic acid applications from the leaves (0, 1, 2 and 3 g L-1) increased the morphological, physical and chemical properties of cucumber plant positively.

Sulphate

Humic acid increased the SO4 content of corn plant very significantly (P<0,01) in unfertilized conditions and significantly in fertilized conditions (P<0,05) as compared to the control. Humic acid type interacted by N2/O2 gases was found at 5% level statistically significant. The highest SO4 content was found as 0,157% at 200 ppm dose of unfertilized wet alkaline technique HA, as 0,165% at 800 ppm dose of HA interacted by N2/O2 gases while it was found as 0,322% and 0,336% at 800 ppm dose of both wet extracted and N2/O2 activated HA in fertilized and unfertilized conditions (Table 2). As compared to the control, the highest change was found as 35,16% and 44,51% at 800 ppm of HA interacted by N2/O2 gases in both unfertilized and fertilized conditions (Table 3; Figure 1 and2). Humic acid applied in fertilized conditions increased the SO4 content of corn plant more when compared with unfertilized conditions. The stimulatory effects of humic substances have been directly correlated with enhanced uptake of macronutrients, such as nitrogen, phosphorus and sulfur (Chen and Aviad, 1990). Danre et al. (2014) informed that maximum concentration of SO4 obtained from when garlic plant were treated with 400 ppm humic acid.

CONCLUSION

There was no difference between humic acid types, but both wet-extracted humic acid and humic acid interacted by N2/O2 gases increased the nutrient element content of corn plant. While humic acid doses were effective on N and Ca nutrition of corn plant in unfertilized conditions due to dilution and anthagonism effects, respectively, it was more effective on P, K, Mg and SO4 nutrition in fertilized conditions. In general, humic acid interacted by N2/O2 gases was found to be somewhat more effective.New studies should be conducted on different plants with different humic acid doses to find out whether humic acid interacted by N2/O2 gases is more effective than humic acid extracted with wet alkaline technique.

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Application of GIS In A Physical Land Evaluation Suitability For

Field Crops (Wheat & Barley)

Orhan DENGIZ, Ayhan HORUZ*

Ondokuz Mayıs University, Faculty of Agriculture, Soil Science and Plant Nutrition Department, 55139 Samsun, Turkey

*e-mail corresponding author: [email protected]

Abstract The objective of this study was to establish spatial model in land evaluation for field crops (wheat-barley) using GIS in Central Anatolia conditions. The study area covers about 34695.6 ha. and is located in South of Ankara. A land unit resulted from the overlay process of the selected theme layers has unique information of land qualities for which the suitability is based on. The selected theme layers of field crops include topographic factor (slope), soil physical factors (available water capacity, soil depth, soil texture-soil structure, drainage) and soil chemical factors (mineral reserves, cation exchange capacity, organic matter, pH-electrical conductivity). These theme layers were collected from existing information. Spatial information of soil physical and soil chemical factors were formulated using soil map database. Slope layer of the study area was prepared from DEM. Each land characteristics is also considered as a thematic layer in the GIS. In addition, each of land quality layers with associated attribute data is digitally encoded in a GIS database. After combination of these layers, a resultant map was produced. Land suitability rating model applied to the resultant polygonal layer provided the suitability classes for field crops. Results showed that 47.8% of the study area is highly and moderately suitable for field crops, whereas 30.7% of the study area is non suitable (currently and permanently) for wheat and barley. In addition, it was found that only 19.1% of the total area is marginally suitable for wheat and barley due to soil and land conditions. The resultant suitability classes were also checked against the only wheat yield which was collected from the field inquiry study and existed data. Result was found to be satisfactory. Key words: Land suitability, soil map, GIS, field crops

INTRODUCTION

Efficient management of natural resources is

essential for ensuring food supplies and sustainability in agricultural development. The task of meeting the demands of man without affecting the ecological assets for the future generations is being given top priority by both scientists and planners. It is indicated that there is an urgent need to match the land resource and the land use in the most possible and logical way to continue sustainable production and to meet the needs of society while conserving fragile ecosystem FAO (1993).

Wheat and barley are important plants among field crops for Turkey and especially for Central Anatolia. A number of organizations and studies are interested in the suitability area for field crops to estimate the production. Systematic approach to produce information on suitability is needed. FAO guideline on the land evaluation system (1983) and parametric model developed by Riquier et al. (1970) are widely used. These systems were based on defined land qualities as related to landuse requirement.

Sys et al. (1991) applied to the concept by FAO is assess the land in irrigated and rainfed areas. Data on crop requirements are also provided (Sys et al., 1993).

The management and analysis of large volumes of spatial data requires computer based systems called Geographical Information System (GIS) which can be used for solving complex geographical and hydrological problems (Garg, 1991). Geographical information system is defined as a system of computer hardware and software designed to allow users to collect, manage, analyse, and retrieve large volumes of spatially referenced data collected from variety of sources (Aronoff, 1991). However, traditional management ability has generally been limited for two reasons: the difficulty in acquiring useful information over vast areas and the lack of a meansfor effective process and analyse the acquired data (Champbell, 1987). Due to many factors that are associated with each feature under study, analysis, manipulation, and using manual methods cost too much. Besides, they consume too much timeor

practically impossible. Today advanced computer programs including decision support systems (Geographic Information System and Remote Sensing) contribute to the speed and efficiency of the overall


planning process and allow access to large amounts of useful information quickly. Especially during the last decade, GIS and RS have received much attention in application related to resources at large spatial scales (Green, 1995; Hinton, 1996). Therefore, GIS is a powerful tool for management and analysis of data required for any land developmental activity. Therefore, systematic approach to produce information on the suitability is needed. The objective of this study was to establish spatial model in land evaluation for wheat and barley by using new technique such as GIS.

MATERIAL AND METHOD

Field Description The study was conducted in the Gölbaşı area and its

vicinity, located south of the city of Ankara (Figure 1) at coordinates 4410120N-471156E, 4410120N-488742E, 4386390N-471156E, 4386390N-488742E. The study area covers approximately 34692.5 ha and includes Mogan and Emir Lakes. These lakes cover 798.6 ha (2.3 %) in total area. The study area consists of various topographic features (flat, hilly, rolling etc.). Flat and rolling physiographic units are particularly common in the study area. Elevation varies from 900 m to 1259 m above sea level. Average annual precipitation and temperature are 410.5 mm and 11.8 oC, respectively. According to soil taxonomy (Soil Survey Staff, 1999), the soil temperature regime and moisture regime were classified as mesic and xeric, respectively. There are 19 different soil series in study area and presented in Table 1. These soil series were classified as Mollisol (33.6%), Inceptisol (32.8%), Entisol (26.8%), and Alfisol (6.8%) (Dengiz, 2002). Forest and rangeland areas generally cover the northern part of the study area, whereas irrigated agriculture is practiced on a very small part located on both sides of the Suksen River and near the other irregular flowing rivers. Dry farming (wheat and barley) and rangeland areas are common in the southern part of the study area. Geologically, the study area consists of dominantly alluvial deposits, limestone, sandstone, marl, clay stone, andesine and metamorphic rocks of the quaternary, tertiary and cretaceous periods (Table 1).

Methodology

The process of evaluating the land in the Gölbaşı

area is adopted the system developed by FAO (1983) and parametric model developed by Riquier et al. (1970). The method to be proposed is intended to design

for assessing land for field crops (wheat and barley) cultivation under

the condition of the Central Anatolia. In order to develop a set of themes for evaluation and ultimately to produce a suitability map for wheat and barley, the crops requirement in terms of land qualities was reviewed (Martin et al., 1976; Kün, 1983; FAO 1983; Elci et al., 1987; Gecid et al., 1987;and Sys et al., 1993). Moreover, results obtained from experimental reports and regional experiences were adopted to identify land quality as related to these yield. The land qualities used for this evaluation include three main land characteristics; i- Topographic factor (slope- E),ii- Soil physical factor (SPF) which includes soil depth (P), drainage (D), available water capacity (H), texture and structure (T), and iii- Soil chemical factor (SCF) which consists organic matter (O), mineral reserve (M), cation exchange capacity (A), and soil reaction or electrical conductivity (N/S). Each factor is considered as a thematic layer in the GIS. Determinations of the various factors and values assigned are summarized in the Table 2.

The topographic factor was based on the slope gradient. The E factor which has predominant effect on the relatively of water during the growing period and on field workability was generated from DEM. Soil physical and chemical factors were calculated using the following formulas which are SPF=D/10*H/10*P/10*T/10 and SCF=O/10*M/10*A/10*N-S/10, respectively. Spatial information on each diagnostic characteristic of SPF and SCF were obtained from digital soil database formed by Dengiz (2002). Each of land characteristics or factors with associated attributed data was digitally encoded in a GIS database to eventually form three thematic layers. The diagnostic properties of each thematic layer were assigned values of factor rating an identified in Table 2. The evaluation model is defined using the value of factor rating as follows;

SI = E * SPF* SCF Where; SI: Suitability Index, E: Slope gradient, SPF: Soil physical factor, SCF: Soil chemical factor

According to values presented in Table 3, these three layers were then spatially overlaid to generate a land suitability map with five classes.


Table 1. Distribution of the soil series and their slope, parent material and land uses

Soil series Taxonomic classes

Area (ha)

Ratio (%)

Slope (%)

Parent material Land use and land cover

Gölcük Bataklığı

Sodic Hydraquent 1477.0 4.53 0-2

Alluvial deposits (clay and siltyclay)

Halophytic plants, swamp and barren land

Kaleboğazı Typic Fluvaquent 1098.7 3.36 0-2 Alluvial deposits pasture

Mogan Typic Xeropsamment 2483.2 7.62 0-2

Alluvial deposits (sandy and gravel)

Rainfed agriculture, rangeland

Orencik Typic Xerofluvent 200.4 0.65 0-2 Alluvial deposits Irrigated agriculture

Recepli Lithic Xerorthent 396.8 1.21 18-30 Limestone Rangeland Oğulbeyi Typic Xerorthent 1463.1 4.49 18-30 Limestone Rangeland Ahlatlıbel Lithic Xerorthent 1620.5 4.97 > 30 Talc schist, schists Rangeland, forest Taşpınarı Typic Calcicxerept

2973.1 9.12 6-10 Limestone Rangeland, rainfed

agriculture and forest Yağlıpınar Typic Calcicxerept 1327.7 4.07 2-4 Marl Rainfed agriculture Ulugüney

sırtı Typic Haploxerept

1543.3 4.03 2-4 Marl Rainfed agriculture and

range land Taşlık Tepe Fluventic Haploxerept


rangeland Gölet Calcic Haploxerept 1216.5 3.73 2-4 Limestone, marl Rainfed agriculture

Çalı Tepe Calcic Haploxerept 2274.4 6.98 2-4 Limestone

Rainfed agriculture and rangeland

Karaoğlan Typic Calcicxeroll 2698.3 8.28 2-4

Claystone, siltystone

Rainfed agriculture

Doğu Tepe Lithic Haploxeroll 1552.1 4.76 18-30 Andesite Rangeland Yavrucak Fluventic Haploxeroll 4510.2 13.84 2-4 Marl Rainfed agriculture Kocadüz Typic Haploxeroll


rangeland 41 Evler Calcic Haploxeralf 1217.7 3.73 2-4 Marl, claystone Rainfed agriculture

Beylikdüzü Mollic Haploxeralf 1011.8 3.10 0-2 Claystone Rainfed agriculture

Figure 1. Location of the study area


Table 2. Factor rating of land characteristics for field crops (wheat and barley)

Land Characteristics Factor rating 10 8 5 2 1

E-Slope (%) 0-5 6-10 11-18 19-30 > 30 P-Depth (cm) 90-120 60-90 30-60 10-30 < 10 and rock

land M-Mineral reserve

Total base (meq) Large reserve

derived from basic or calcareous rocks

Total bases 100-300

Good reserve derived from

basic or calcareous rocks

Total bases 50-100

Moderate reserve derived from sandy

materials or ironstone rocks

Total bases 20-50

Low reserve derived from

acid rocks Total bases

10 -20

Very low reserve. Total bases

< 10

D-Drainage & water table (cm)

Good > 120

Moderate 80-120

Moderate 50-80

Poor 30-50

Very poor or excessive

0-30 H-Available Water Capacity AWC-mm

>160 120-160 80-120 40-80 < 40

T- Texture & Structure Si: Silty, C: Clay, S: Sand, L: Loam, GS: Gravel, f: fine, C+%60, C-%60

L, SiL, SCL, CL Granular to angular

SC, C-%60, SiCL, SiC Angular to prismatic

C+%60, SiC Coarse prismatic and

columnar

SL, fSL, Si Massive- low porous, single

grain and platy

GS, S, LS Single grain, massive-no-

porous

A-Cataion Exchange Capacity

(CEC -cmol kg-1/clay)

> 40

20-40

10-20

5-10

<5

O- Organic Matter (%) > 3 3-1.5 1.5-1 1-0.5 < 0.5 N/S- pH or EC

(dS m-1) 6.5-7.5

0-4 7.5-8.2

4-8 5.0-6.0/8.2-8.5

8-12 4.5-5/8.5-9.0

12-16 3.5-4.5/9.0-

10 > 16

Schematic chart of the spatial overlay showing the land characteristics and model is given in Figure 2.

Figure 2. Schematic chart of GIS application to land suitability for wheat and barley

RESUAND DIS


CUSSION


The study provides an approach to identify

parametric values in modelling the land suitability for wheat and barley. The result indicated that approximately half of the study area (47.8%) is highly and moderately suitable area where is common on the Yavrucak, Gölet, Yağlıpınar, Beylikdüzü, 41Evler and

Örencik soil series. The marginally suitable land covers about 6621.9 ha and is generally located on Çalı Tepe,

Kocadüz Tepe, Mogan and Taşlık Tepe soil series

(Table 4).

Table 4. Distribution of suitability classes of the study area

Suitability class Area (ha) % Highly (S1) Suitable 9236.7 26.6 Moderately (S2) Suitable 7369.8 21.2 Marginally (S3)Suitable 6621.9 19.1 Non suitable (currently) (N1) 4312.6 12.4 Non suitable permanently) (N2) 6352.9 18.3 Lake 798.6 2.3 Total 34 692.5 100

Available moisture status of these soil series was

found to be the most limiting factor for crop production. By improving the soil moisture status, the potential productivity can be increased to status of moderately suitability class. The only 30.7% of the study area is unsuitable land for wheat and barley which correspond to the high slope gradient, pH - EC values and low available water capacity, high water table, poor drainage, shallow depth, low organic matter, coarse texture and weak soil structure. These limiting factors were generally found on Gölcük Bataklığı, Ahlatlıbel,

Oğulbeyi, Mogan, Doğu Tepe and Recepli soil series

(Figure 3). To assess the reliability of the methodology developed, the suitability classes were checked against the only the wheat yield. Average wheat yield is about 2000 kg ha-1 in Turkey. The wheat yield data collected between 2003 and 2005

from the study area were average 2135, 1927, and 1058 kg ha-1 for the unit of class generated S1, S2 and S3 respectively. For more accurate results, average wheat yields should be periodically collected after 2005. In addition, this verification should be made for barley to establish the result in relation to field crops (wheat and barley). In addition, Mongkolsawat and Kuptawutiana (1997) who studied to establish spatial model in land evaluation for rice using GIS in the lower Namphong watershed located in Northeast Thailand determined the highly suitable land cover an area of about 208.3 km2 and some 17.7% of the watershed is unsuitable area for rice which corresponds to the slope land. The resultant suitability class were checked against the rice yield which collected by the Department of Agriculture Extension and they found that it was to be satisfactory.

CONCLUSION

The study thus confirms the capability of GIS to integrate spatial and attribute data and offers a quick and reliable method of land suitability with higher accuracy. The spatial relationship between different geographically referenced data can be established using a GIS. In addition, the modelling provided an approach to the improvement of wheat and barley yield by enhancing the component of modelling input. In the present study, soil database and topographic map have been used as vital tools to generate land suitability map. In conclusion, according to the potentialities and constraints of the region with regard to its land resources, this parametric approach modelling in GIS will also be a useful tool for rainfed agricultural planning.


Figure 3. Land suitability map for field crops (wheat-barley) in Gölbası-Ankara

REFERENCES

Aronoff, S. Geographic Information System: A management perspective. WLD Publ. Ottawa, ON, Canada, 1991.

Champbell, J. B. Introduction to remote sensing. The Guilford press, New York., 1987.

Dengiz, O. Ankara-Gölbaşı özel çevre koruma alanı ve yakın

çevresinin arazi değerlendirmesi. Doktora Tezi, Ankara Üniversitesi, Fen Bilimleri Enstitüsü, 2002,p. 249.

Elçi, S.; Kolsarıcı, Ö.; Geçit, H. Tarla bitkileri. A.Ü. Ziraat Fakültesi

Yayınları:30, Ders Kitabı, Ankara, 1987. FAO. Guideline for land use planning. FAO development series No:

1, ROME, 1993, p. 96. FAO. Guidelines: Land evaluation for rainfed agriculture soils.

Bulletin 52. ROME: 237, 1983. Garg, P. K. Development of a catchments scale erosion model for

semiarid environment and its implementation through Remote Sensing. PhD Thesis. University of Bristol, UK., 1991.

Geçit, H.; Kolsarıcı, Ö.; Erol, S. Tarla bitkileri. A.Ü. Ziraat Fakültesi Yayınları: 1008, Ders Kitabı, Ankara, 1987.

Green, K. Using GIS to predict fire behaviour. J. Forestry, 1995, .93: 21-25.

Hinton, J. C. GIS and RS integration for environmental applications.

Int.J. Geo. Inf. Sys. 1996, 10:877-890. Kün, E. 1983. Serin iklim tahılları. Ankara Üniversitesi Ziraat

Fakültesi. Yayınları: 240, Ders Kitabı, Ankara, p, 225 . Martin, J. H.; Leonard, W. H.; Stamp, D. L. Principles of field crop

production, third edition. MacMillan Publishing Co. Inc. NewYork, p. 118.

Mongkolsawat, C. P. and Kuptawutiana, P. 1997. A physical evaluation of land suitability for rice: A methodological study using GIS. http://www.gisdevelopment.net., 1976.

Riquier, J.; Bramo, D. L; Cornet, J. P. A new system of soil appraisal in terms of actual and potential productivity. FAO- AGRL. TESR/70/6, ROME, 1970.

Sys, C.; Ranst, V.; Debaveye, J. Land evaluation part I, part II Agricultural publication No: 7, ITC, Ghent, 1991.

Sys, C.; Ranst, V.; Debaveye, J.; Beernaert, F. Land evaluation part III, crop requirements. Agr. publication No. 7, ITC, Ghent, 1993.


The Effect of the Rates of Different Organic Fertilizers on Restoring Productivity of Eroded Soils

Nutullah ÖZDEMİRa, Tugrul YAKUPOĞLUb,Ayhan HORUZa* aOndokuz Mayıs University, Department of Soil Science and Pland Nutrition, 55139 Samsun, Turkey

bKahramanmaraş Sütçü İmam University, Department of Soil Science and Pland Nutrition, 46040 Kahramanmaraş,

Turkey


Abstract The objective of the present study was to find out the effect of incorporation of various organic matter sources such as tobacco waste (TB), tea waste (TE) and bio-solid (BS) on the restoration of the productivity eroded soil. The organic matter sources were incorporated into three different levels of the studied eroded soil. A bulk surface (0-20 cm depth) soil sample was taken from Samsun, in the north of Turkey. Some properties of the soil were determined as follows; fine in texture, moderate in organic matter content, moderate in pH and free of alkaline problem. The soil samples were treated with the organic materials at four different levels including the control treatments and each treatment was replicated three times in a randomized factorial block design. The soil samples were incubated for 4 weeks. After the incubation period, tomato plants were grown in all pots. The organic matter treatment increased the productivity of the eroded soil significantly. Effectiveness of the treatments varied depending on the types of organic matter and levels of soil erosion. Key words: Productivity, erosion, organic fertilizer.

INTRODUCTION

Soil erosion is a major environmental threat to

the sustainability of the World’s agricultural

production because of its negative effect on soil productivity (Pimentel et al., 1995). In Turkey, It is noticed that soils have erosion damage of up to 80%. Many fields throughout the semi-arid lands exhibit characteristics of low soil productivity associated with erosion events. Therefore, it is very important to take effective measures to protect soil and water of agricultural fields in Turkey. Growers have several options for correcting or compensating for soil erosion and restoring productivity of these types of soils. The most common approach is to apply additional organic and chemical fertilizers to eroded areas to improve crop growth and reduce the potential of further erosion. However, large quantities of commercial fertilizer may not improve yields to the level of non-eroded soil (Olson, 1977; Mbagwu et al., 1984; Tanaka & Aase, 1989; Malhi et al., 1994 Larney & Janzen, 1996).

Recent interest in sustainable cropping systems

has focused renewed attention on the use of organic materials as fertilizers. Livestock manure and bio-solids

(BS) are a restorative option (Dormaar et al., 1988; Larney & Janzen, 1996) but only where they are available on-farm or within a short hauling distance (Freeze et al., 1993). However, there is a scarcity of information on the rates of manure necessary to restore productivity of eroded soils, especially in arid and semi-arid areas (Parr et al., 1989). Traditionally, all areas of a field receive the same application rate of fertilizer irrespective of inherent soil quality (e.g., soil type, nutrient status, organic matter content, level of erosion).

Malhi et al. (1994) compared the response of

barley growth to topsoil removal for two different soils. Considering the soil data, they reported that nutrient content declined strongly with depth for the Peace Hills soils whereas for the Malmo soil, nutrient content remained fairly constant with depth. However, the bulk density of the Malmo soil, which contains high clay content than the Peace Hills soil, increases more rapidly than that of the Peace Hills soil. This assumption is confirmed by the fact that the application of fertilizers fully restored productivity of the Peace Hills soils, but only had a limited effect on the Malmo soils.


Understanding crop yield responses to soil

erosion is of vital importance in assessing adequately the

vulnerability of agriculture to erosion. Correct understanding of the effect of erosion on crop productivity is not only important for soil conservation per se; decisions about land use by individual farmers are at least to some extent determined by the way in which farmland productivity is affected by erosion. For example, research suggests that in some parts of the Mediterranean, the productivity of certain crops has decreased to such an extent as a result of erosion, that land use change was inevitable (Marathianou et al., 2000). Thus, understanding past and predicting future land use changein erosion-prone areas depend on an accurate understanding of the relationship between soil erosion and productivity.

The objective of this present study was to determine the contributions of incorporated tobacco waste (TB), tea waste (TE) and bio-solid (BS) into three levels eroded soil on the restoration of productivity.


Soil samples (0-20 cm depth) of a soil type

classified as Verticcalciudoll according to the US. Taxonomy (Soil Survey Staff, 2003) were taken from Samsun, in the north of Turkey. The BS was obtained from Bafra Municipality, TB was obtained from Ballıca

Tobacco Plant and TE was obtained from Institute of Tea Research in Rize. Soil samples were treated with four different levels (0, 2, 4 and 6%; w/w) of organic residues including the control treatments and each treatment was replicated three times in a split block design [(3x3x4)x3]. All of the pots were incubated at water content of field capacity and 20oC for 4 weeks.

After incubation period, tomato plants (cv. Tore F1) were grown in a greenhouse study. Tomato seeds were sown into multi modular seed trays (3 × 3 cm cell size) with 120 cells. After emergence, seedlings were pricked out to transplant in plastic pots (height 10 cm, diameter 9 cm). Seedlings were planted at the stage of four true leaves into plastic pots (height 20 cm, diameter 19 cm). One hundred and twelve days after planting, tomato plants were removed from the pots and the experimental work ended. All soil samples including control were manually ground to pass through a 2 mm sieve.

After growing tomatoes, physical and chemical soil properties were determined as follows; soil organic matter content was measured by a modified Walkley-Black method in soil samples sieved through a 0.5 mm sieve (Nelson & Sommers, 1982); soil texture was determined by hydrometer methods (Demiralay, 1993);

pH and EC values in 1:2.5 soil:water (w/v) suspension

were measured by pH meter and EC meter, respectively (Rowell, 1996); cation exchange capacity and lime content were determined according to Kacar (1995); total

nitrogen content was determined according to Rowell (1996). Soil properties except for soil organic matter content were determined in samples sieved to 2 mm.

Some physical and chemical properties of slightly, moderately and severely eroded soils are given in Table 1. Changeable sodium percentages in the soils were under 15% and there is no problem of alkalinity of the soils (Soil Survey Staff, 2003). Nutrient and heavy metal contents of organic residues were determined according to Kacar (1972). Some properties of organic wastes are shown in Table 2.

Dry weights of the above ground portions of the tomato plants were determined after oven-drying in containers at 65o C for at least 72 h. Statistical analyses of results were carried out by SPSS computer programme. LSD of the means were determined and compared for significant differences at p < 0.05.

Table 1. Some chemical and physical characteristics of

slightly to severely eroded Vertic calciudoll from the Samsun region of Northern Turkey.

Soil properties

Erosion levels*

1 2 3

Particle size distribution (%)

Sand (S) 14.6 13.1 15.2 Silt (Si) 26.0 30.8 31.7 Clay (C) 59.4 56.1 53.1

Textural class C C C pH, in 1:2.5 soil-water as w/v 8.0 8.1 8.1 EC, in 1:2.5 soil-water as w/v (dSm–1) 0.79 0.65 0.64 Organic matter content (OM) (%) 0.99 0.84 0.83

Total N (%) 0.14 0.13 0.11 Cation exchange capacity (meq 100 g–

1) 37.4 23.9 21.4

Lime content, (%) 16.6 19.4 21.9 *1: Slightly; 2: Moderately; 3: Severely.


Table 2. Chemical properties of organic wastes applied to Vertic calciudoll subjected to multiple levels of erosion.

Properties*

Conditioners

TB TE BS Organ

ic Non-

organic

OC (%) 38.40 54.78 22.20

N (%) 1.97 2.45 2.40 C:N 19.50 22.36 9.25

Fe2O3 (%) 2.30

CaO (%) 11.50

MgO (%) 1.34

P (%) 1.30 K (%) 0.23

NaO (%) 0.22

Al2O3 (%) 4.40

Cd (µg g–1) 6.30

Cu (µg g–1) 214.50 Cr (µg g–1) 135.20

Pb (µg g–1) 180.40

Ni (µg g–1) 75.80

Zn (µg g–1) 435.90 *Quantities of nutrients and heavy metals were determined as total.


Total Dry Matter Yield Total plant dry weights of tomato plants grown in

a greenhouse with soil samples from slightly, moderately and severely eroded areas treated with different organic wastes are shown in Figure 1 and Table 3. The organic wastes added to soils had significant effects on total plant dry weight of tomato depending on type and application levels of the organic wastes and the degree of soil erosion. As the level of soil erosion increased, from slight to severe, total plant dry weight declined accordingly (Figure 1). Total plant dry weight of tomato plants grown in slightly, moderately and severely eroded soil samples are found to be 36, 29 and 26 g pot-1, respectively (Figure 1). When the relationship between the level of soil erosion, applied organic wastes (TB, BS and TE) and total plant dry weight was taken into consideration, mean plant dry weights were found to be 124, 117 and 111 g pot-1 for slightly, moderately and severely eroded soil, respectively (Figure 1). Over the mean plant dry weight, the organic wastes applied to the soil samples increased total plant dry weight in tomato (Figure 1). It was also found that 2% doses of the organic wastes applied to the moderately and severely eroded soils resulted in recovery of the soils from the erosion effect and increased plant dry weight of the tomato plants grown in these soils up to the level of the productivity of slightly eroded soil samples. However, as the level of soil

erosion increased, the rate of rise in plant dry weight declined accordingly

When the effect of the types of organic wastes applied to the soil samples on total plant dry weight was taken into consideration, it was found that there were significant (p < 0.05) differences amongst the organic wastes (Figure 1). As seen in Figure 1, application of TB, BS and TE to the soil samples increased total plant dry weight such that total plant dry weight per pot obtained from applications of TB, BS and TE were found to be 166, 109 and 77 g pot-1, respectively.

In a descending order of TB, BS and TE, organic wastes affected total plant dry weight in tomato (Figure 1). The lowest total plant dry weight was obtained from the plants grown in TE-amended soil samples. The reason for this is that TE is composed of more difficult to decompose particles then TB and BS. Total plant dry weight of tomato per pot increased in accordance with application doses. While total plant dry weight per pot for the plants grown in untreated soil samples was 31 g pot-1, it increased to 141 g pot-1 with the application of 2% dose, to 147 g pot-1 with the application of 4% dose and 150 g pot-1 with the application of 6% dose of organic wastes (Figure 1). When the combined effect of application doses and the type of organic wastes was examined, it was found that total plant dry weight increased with the rise in application doses of organic wastes. However, the effect of application doses of BS on total plant dry weight differed from other organic wastes as the level of effect of the doses of 4% and 6% for all erosion levels declined. The decline in the effect of application doses was more marked with the dose of 6%. This case can be explained through the composition of BS.

CONCLUSION

There was also a negative relationship between erosion degree of the soil samples and total plant dry weight. Organic wastes (TB, BS and TE) added to the soil samples increased plant dry weight depending on the application levels. It was found that the effectiveness of the soil amendments on average increases in total plant dry weight was in order of TB > BS > TE for all erosion degrees.

Table 3 . Mean plant dry weight of tomato plants grown in different soil samples treated with different doses of organic wastes.


Erosion levels Slightly Moderately Severely

Crop (g pot–1) 123.9a+ 117.0b 110.8c

Organic wastes TB BS TE

Crop (g pot–1) 165.7a 109.0b 77.0c

Doses (%) 0 2 4 6

Crop (g pot_1) 30.7 a 141.1 b 147.1 c 150.1 d +Values followed by the some letter are not significantly different according to the LSD0.05

Figure 1. Total plant dry weight of tomato plants grown in roded soils (slight, moderate and severe) treated with different organic wastes (TB: Tobacco waste, BS: Bio-solid and TE: Tea waste) at different application doses (0, 2, 4 and 6%)

REFERENCES

Demiralay, İ..ToprakFizikselAnalizleri. Atatürk ÜniversitesiZiraatFakültesiYayınları, Erzurum, Turkey, 1993, 143, 2–42,

Dormaar, J.F.;Lindwall, C.W.;Kozub, G.C. Effectiveness of manure and commercial fertilizer in restoring productivity of an artificially eroded Dark Brown Chernozemic soil under dryland conditions. Canadian Journal of Soil Science,1988, 68, 669–679.

Freeze, B.S.; Webber, C.;Lindwall, C.W.; Dormaar, J.F. Risk simulation of the economics of manure application to restore eroded wheat cropland. Canadian Journal of Soil Science, 1993,.73, 267–274.

Kacar, B. BitkiveToprağınKimyasalAnalizleri II, BitkiAnalizleri. Ankara ÜniversitesiZiraatFakültesiYayınları, 453, Ankara, Turkey, 1972.

Kacar, B. BitkiVeToprağınKimyasalAnalizleri III. Ankara ÜniversitesiZiraatFakültesiYayınları, Eğitim, AraştırmaveGeliştirmeVakfıYayınları. No 3, Ankara, Turkey, 1995.

Larney, F.J.;Janzen, H.H. Restoration of productivity to a desurfaced soil with livestock manure, crop residue and fertilizer amendments. Agronomy Journal, 1996, 88, 921–927.

Malhi, S.S.;Izaurralde, R. C.;Nyborg, M.; Solberg, E.D. Influence of topsoil removal on soil fertility and barley growth. Journal of Soil and Water Conservation, 1994, 49, 96–101.

Marathianou, M.; Kosmas, C.;Gerontidis, S.;Detsis, V. Land-use evolution and degradation in Lesvos (Greece): a historical approach. Land Degradation and Development, 2000,11, 63–73.

Mbagwu, J.S.C.; Lal, R.; Scott, T.W. Effects of desurfacing of

Alfisols and Ultisols in southern Nigeria, Soil Science Society of America Journal, 1984, 48, 828–833.

Nelson, D.W.; Sommers, L.E. Total carbon, organic carbon and organic matter. In Methods of Soil Analysis, Part 2, Chemical and Microbiological Properties,Agronomy Monograph No. 9, (A.L. Page, ed.) ASA, SSSA; Madison, WI, U.S.A., 1982, pp. 539–580,

Olson, T.C. Restoring the productivity of a glacial till soil after topsoil removal. Journal of Soil and Water Conservation, 1977,32, 130–132.

Özdemir, N. Toprakve Su Koruma. OndokuzMayısÜniversitesiZiraatFakültesiDersKitabıYayınlar, Samsun, Turkey, 2002, 22, 68–73

Parr, J.F.;Papendick, R.I.;Hornick, S.B.;Colacicco, D. Use of organic amendments for increasing productivity of arid lands. Arid Soil Research and Rehabilitation, 1989, 3, 149–170.

Pimentel, D.; Harvey, C.;Resosudarmo, P.; Sinclair, K.;Kurz, D;, McNair, M.; Crist, S.;Shpritz, L.;Fitton, L.;Saffouri, R.; Blair, R. Environmental and economic costs of soil erosion and conservation benefits. Science,1995, 267, 1117–1123.

Rowell, D. L. Soil Science Methods and Applications. Wesley Longman Limited; Harlow, U.K.,1996.

Soil Survey Staff .Official Soil Series Descriptions. U.S Department of Agriculture, Natural Resources Conservation Service, National Soil Survey Center; Lincoln, NE., 2003

Tanaka ,D.L.; Aase , J.K. 1989. Influence of topsoil removal and fertilizer application on spring wheat yields. Soil Science Society of America Journal, 53, 228–232.


The Enhancement effect of Cetyltrimethylammonium Bromide in the Electrochemical Response of Carbon Paste Electrode to Nitrophenols

Arsim MALOKUa, Liridon S. BERISHAa, Granit JASHARIa, Eduard ANDONIb, Tahir ARBNESHIa

aDepartament of Chemistry, Faculty of Mathematics and Natural Sciences, University of Prishtina, “Hasan Prishtina”,

Pristina, Kosovo bDepartament of Chemistry, Faculty of Natural Sciences, University of Tirana, Tirana, Albania


Keywords:Electrochemical methods, DPV, Nitrophenols, Carbon paste electrode, Cetyltrimethylammonium bromide

INTRODUCTION

The presence of nitrophenols (NPs) in the

environment is related with their production and usage, so natural sources for NPs are not usually found. NPs are known as widespread components in industrial ingredients and consequently in industrial waste. NPs are used in paints, adhesives, explosives, pesticides, polymers, processing leather and paper, and pharmaceutical manufacturing [1-6]. Also some of them can be generated or produced as intermediate products from different processes [1,3,5,6]. They are among others major and persistent pollutants of the environment and are considered as primary pollutant components in wastewater due to their high toxicity, high oxygen demand and low biodegradability [1-3,7–

10]. Many of the phenols including nitrophenolshave been listed in the U.S.A. Environmental Protection Agency (EPA) as Priority Pollutants, because of their toxic effects on humans, animals, and plants [2,11,12]. The harmful effects of phenols and their derivatives may result in acute poisoning, histopathological changes, mutagenicity and carcinogenicity [1,6]. Therefore, qualitative and quantitative detection of phenols and substituted phenols is of great importance in environmental monitoring and control.Lot of methods have been reported on the determination of the target compounds, namely colorimetry, spectrophotometry[13], gas chromatography[1,14], high-pressure liquid chromatography (HPLC) [15],capillary electrophoresis [16], and electrochemical methods[2,3,11,17]. Among them, conventional colorimetry and spectrophotometry are easily interfered by other colored components. The mentioned methods require also a long time for sample pretreatment and consume lots of chemicals which may cause other environmental issues. Electrochemical techniques haveattracted considerable interest due to their

suppleness, convenience, and low cost compared to other existing methods [18]. In terms of nitrophenols and related compounds, waste treatment and detection are two major research directions. In both fields electrochemical methods are of prime importance [2,8-12,19-22]. Most of these methods are based on the direct oxidation or reduction of the substrate on an electrode surface. Carbon paste electrodes (CPEs) are widely used as the working electrode because they are simple and easy to prepare and to handle. To enhance the electrochemical response of CPEs great efforts have been made by chemical and electrochemical modification [23-25]. Our current study is focused on the use of cetyltrimethylammonium bromide (CTAB) as a means to increase the sensitivity of the electrode surface towards NPs. Knowing that CTAB is a cationic surfactant which owns both polar and non-polar region in its molecule, it has ability to attach to the lipophilic surface of the electrode and thus may influence the physicochemical and electrochemical processes occurring there. The compounds investigated in this work represent phenols most commonly present in the environment and human surroundings that reveal toxic influence towards living organisms, including humans [1-5,26-30].


Electrochemical behaviors of NPs At first the impact of CTAB for improving the CPE response tonitrophenols (NPs) was studied by cyclic voltammetry measurements in the potential range of 0.4 to -1.0V vs Ag/AgCl in 0.1 mol L-1 phosphate buffer, pH 7.0, is shown in Fig. 1.


Fig. 1. Cyclic voltammograms of 2-nitrophenol (A), 3-nitrophenol (B), 4-nitrophenol (C), 2,4-dinitrophenol (D), and 4,6-dinitro-o-cresol (E) in the presence of 0.20 mM CTAB (curves 1) and in the absence of CTAB (curves 2); concentration of nitrophenols 100 ppm; scan rate 100 mV/s, supporting electrolyte 0.1 M PBS pH 7.0. This figure shows the behavior of the CPE in presence (curves 1) and absence (curves 2) of CTAB to the five NPs. From cyclic voltammograms shown in Fig. 1A-E it seems that modification of CPE with 0.20 mM CTAB has significantly increased the sensitivity of the CPE to NPs. Cyclic voltammograms presented for 2-NP, 3-NP, and 4-NP (Fig. 1A-C, curves 1) show that in potential range of -0.65 to -0.85V depending on NPs, appears a more sensitive current peak during the cathodic sweep for each NP, this could be attributed to reduction of nitro group (-NO2) to hydroxylamine group (-NHOH) [2,3]. In this sense, these peaks were chosen for further experiments. Also Fig. 1D-E shows the appearance of two more sensitive peaks from the cyclic voltammograms of 2,4-DNP and 4,6-DNOC in the potential range of -0.65 to -0.95V, this may be attributed to the presence of two nitro groups in these NPs. So these peaks were chosen for further experiments. In the presence of CTAB, a positively charged hydrophilic film formed at the electrode surface. Under critical micelle concentration of the CTAB, the surfactant molecules can be firmly adsorbed on the CPE surface via hydrophobic interactions between the long C-H chain and the paraffin oil. Herein, the hydrophobic C-H chain of CTAB adsorbs on the CPE surface and the positive charged head groups direct toward the aqueous solution [31-33]. Under the strong hydrophobic interaction between NPs and the assembled C-H chains,

the accumulation efficiency of NPs on the CPE surface certainly enhances obviously. Moreover, the adsorbed C-H chains provide a more effective electron transfer channel between NPs and surface electrode. As a result, electrochemical activity of CPE is improved effectively in the presence of CTAB and the current signals enhance greatly. As reported previously [2,3,32,34], suggestion electrochemical mechanism reaction includes irreversible reduction corresponded to the direct reduction of nitrophenols into hydroxylaminophenols with four electrons and protons transfer process (Eq. (1)). Furthermore reversible redox couple, attributed to two electrons transfer on hydroxylaminophenolselectrogenerated to nitrosophenols (Eq. (2)). The other reversible redox couple suggest oxidation of hydroxyl group: HOC6H4NO2 + 4H+ + 4e- → HOC6H4NHOH + H2O (1) HOC6H4NHOH – 2H+ – 2e- ↔ HOC6H4NO (2) Enhancement effect of CTAB

Based on results obtained in CV and in order to test electrocatalytic activity of CPE we have established DPV and amperometric measurements. The impact of CTABin improving the CPE response to NPs has shown better results in DPV and measurements conducted in potential range -0.4 up to -0.9V (Fig. 2) referring to the more sensitive reduction peaks of NPs appeared in CV from -0.6 up to -0.9V depending on the NPs.

Fig. 2. Differential pulse voltamograms of nitrophenols in the presence (curves 1) and in the absence (curves 2) of 0.20 mM


CTAB; 2-nitrophenol (A), 3-nitrophenol (B), 4-nitrophenol (C), 2,4-dinitrophenol (D), and 4,6-dinitro-o-cresol (E); concentration of nitrophenols 13 ppm; supporting electrolyte

0.1 M PBS pH 7.0; scan rate 20 mV/s, pulse amplitude 50 mV.

All NPs have been tested in response to unmodified and modified CPE with CTAB 0.20 mM in phosphate buffer solution pH 7.0. In Fig. 2A can be seen that adding 0.20 mM CTAB in phosphate buffer solution pH 7.0 CPE-CTAB gives a reduction peak in potential -0.595V as a response to 2-NP (13 ppm) with current intensity -19.548µA (curve 1) attributed to the presence of one nitro group attached to the aromatic ring, although the unmodified CPE shows no signal (curve 2). An increase about 7 times in reduction current was observed for 3-NP with concentration 13 ppm (Fig. 2B) using CPE sensor in presence of 0.20 mM CTAB (curve 1) and in absence of CTAB (curve 2). Peaks appear at potentials -0.585V respectively -0.620V with current intensity -20.328µA respectively -2.912µA. Significant increase (about 14 times) of peak current shows CPE-CTAB as response to 13 ppm 4-NP (Fig. 2C) with peak intensity -21.568µA in potential -0.709V compared to CPE with peak intensity -1.537µA in potential -0.739V. From the Fig. 2D it seems that for 13 ppm 2,4-DNP appears two reduction peaks with CPE-CTAB (curve 1) in potentials -0.545V and -0.709V, with current intensity -54.734µA respectively -33.719µA attributed to the presence of two nitro groups attached to the aromatic ring, and also two low intensity reduction peaks with CPE (curve 2) in potentials -0.605V and -0.764V with intensity -1.698µA respectively -1.445µA. In case of 2,4-DNP we see an increase in peaks current about 32 respectively 23 times.Also DPV voltammograms of 4,6-DNOC (13 ppm) show two reduction peaks due to the presence of two nitro groups attached to the aromatic ring (Fig. 2E). With CPE-CTAB the peaks appear at potentials -0.535V and -0.705V with intensity -48.247µA respectively -36.598µA (curve 1) and lower intensity peaks are appeared with CPE in potentials -0.59V and -0.744V with intensity -1.507µA respectively -10.31µA. It shows an increase with CPE-CTAB for about 32 respectively 3.5 times compared to CPE. In comparison to unmodified CPE peak potentials to all NPs investigated on the CPE-CTAB are shifted positively and currents are increased from 7 up to 32 times depending on the NPs.

Amperometric characterization The effect of the applied potential vs Ag/AgCl on the amperometric response of the CPE and CPE-CTAB have been investigated. The developed sensor presented a better sensitivity when potential of -0.5V to -0.7V vs Ag/AgCl was applied to the working electrode, therefore these potentials were chosen for the amperometric measurements. Modified CPE in comparison to unmodified sensor has shown better sensitivity and lower detection limit as a response almost for all NPs (Table 1). Table 1. Comparison of analytical performance of CPE in absence and presence of 0.20 mM CTAB to NPs by amperometry.

CONCLUSION

In this work, a novel modification of CPE was investigated in response to nitrophenols by electrochemical techniques including CV, DPV, and hydrodynamic amperometry. The results indicated that the electrochemical response of 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, and 4,6-dinitro-o-cresol could be enhanced by the CTAB film due to its high surface area, excellent catalytic capability, and high absorptivity. The process of CPE modification was easy and simple. Therefore, a novel method with high sensitivity, good repeatability and stability for determination of above mention NPs was developed.

ACKNOWLEDGEMENTS

The authors acknowledge the financial support of the Ministry of Education, Science and Technology of the Republic of Kosovo in the framework of support


for small grants and CEEPUS III (CIII-CZ-0212-09-1516) network.

REFERENCES

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A Comparative Study on Enzymatically and Chemically Synthesized

Maleic anhydride-Styrene Copolymer

Ersen YILMAZ* *Department of Metallurgical and Materials Engineering, Faculty of Engineering, Munzur University, Tunceli, Turkey


Keywords: enzymatic synthesis, characterization, maleic anhydride, copolymer.

INTRODUCTION

Maleic anhydride (MA) is a functional or reactive monomer. Its presence in a backbone gives a functionality or reactivity to a polymer. In the same way Maleic anhydride-Styrene (MASt) copolymer can be regarded as a functional or reactive polymer. The functionality is brought about by the maleic anhydride in the backbone of the copolymer which is reactive towards nucleophilic reagents (H2O, alcohols, thiols, ammonia, amines, etc). Introduction of nucleophilic compounds enables the synthesis of new materials.1 The importance of Maleic anhydride-Styrene copolymers is attributed to their usage in a number of areas for various purposes. Its applications comprise additives that are used to upgrade properties of styrenic polymeric material, coating additives, binder application, additives for building materials, microcapsules, blend compatibilizer, adhesion promoter for polyolefin coatings on metals and medical and pharmaceutical applications.2 MASt is known to be a biocompatible polymeric material. Its biocompatibility is attributed to the combination of hydrophilic maleic anhydride and hydrophobic styrene units in the backbone of the copolymer. It has been used in many applications such as drug and protein delivery vehicles to the biological environments of different pH.3 MASt has also been used as male contraceptive.4 The contraceptive consists of a MASt which is prepared by the step of irradiation at a dose of 0.2 to 0.24 megarad for every 40 g. of the copolymer. The contraceptive consists of an injectable fluid of MASt and pure dimethyl sulphoxide. The polymer has some antiviral activity when tested for anti-HIV virus activity.5 Enzymes with varying structures are capable of initiating or catalysing many chemical reactions. Some of them produce homopolymers of esters, carbonates, amides, phosphates, saccharides, while some are first able to break C-C bonds of circular monomers and then begin polymerization.6,7 For example, recently, many lipase-catalyzed ring-opening polymerization reactions have been reported.8-12 Some other enzymes break double bonds between C atoms, in particular, of vinyl

monomers, and then begin the polymerization under mild conditions.13-15 Using enzymes in chemical reactions can sometimes be more advantageous over classical chemical reactions.16-

20 In the synthesis of polymers, for example, one important advantage of using enzymes, often known as biocatalysts, is the production of polymers with defined molecular weight.21,22 Biocatalysts act specifically on the substrate, operate under mild reaction conditions, such as relatively low temperatures, and often do not produce environmentally harmful waste materials.23 Chemical syntheses and/or modifications, beside high temperature, often require the use of harsh chemicals, organic solvents or precipitants. Hence, recently, enzymatic polymerization has been receiving more and more attention as an alternative method. To date, MASt copolymer have been synthesized by employing various chemical methods.24 The present work constituted enzymatic synthesis of MASt copolymer, and characterization and comparison of its some physical properties with those of MASt produced by using chemical method.


FTIR spectra of both copolymers were shown (Fig. 1) and characteristic peaks of MA and St were given (Table 1). As can be seen (Table 1), both copolymers were synthesized successfully by using either of methods. Intensity of anhydride’s carbonyl peaks of

enzymatic copolymer appeared to be lower than their chemical counterparts (Fig. 1). Here it was evident that the anhydride and carbonyl groups existing within the copolymer of enzymatic reaction formed cross-links with –NH2 groups of the amino acids of the enzyme. In the FTIR spectra of the enzymatic copolymer, weak –

NH2 peaks seen between 3676 and 3650 cm-1 could be taken as the evidence of the cross-link. Another clue for the presence of the cross-link was obtained from the dissolvability of the copolymers in Tetrahydrofuran


(THF). The chemically synthesized polymer was readily dissolved in THF, whereas it was impossible to dissolve the other copolymer produced by enzymatic synthesis.

Figure 1. FTIR spectra of Ma-St copolymer synthesized by both methods. Table 1. Characteristic peaks of two MA-St copolymers

SEM images (10,000 times enlarged) of the copolymers were obtained (Fig. 3). Here it could be seen that the chemical copolymer included more spacing within its structure, thus having relatively lower density. It could be understood form the SEM images of the copolymer produced by enzyme that polymerization occurred as laminar and this state fairly decreased the spacing of the polymer chains. The laminar structure improved its mechanical properties and led to a more stiffened structure. Therefore SEM results suggested that in vitro enzymatic synthesis of MA-St resulted in a product with higher density.

(a)

(b) Figure 2. SEM Images of coplymers (a) Enzymatic (b) Chemical TGA curves of the copolymers were plotted (Fig. 3) and their characteristic degradation temperatures were listed (Table 2). These included initial reaction temperature (Ti), half time temperature (Th), maximum rate temperature (Tm), final reaction temperature (Tf), maximum rate (Rm), and amount of remained substance at maximum rate (Cm). TGA results indicated that the chemically synthesized copolymer followed a two step degradation pattern while the other was degraded in a single step. Single step thermal degradation could imply that the enzyme produced copolymer has a much wider range of working temperature and of course wider industrial applications.

Figure 2. TGA Curves of both copolymers Reaction conditions, yield and water solubilities of the copolymers can be seen at (Table 2). Enzymatic synthesis appeared to provide a better alternative synthesis method. It appeared to have milder reaction conditions (low temp., time and yield), and has better solvent resistance against to THF which is normally a solvent for MA-St, in terms of the product.


Table 1. Reaction conditions, yield and water solubilities of copolymers

REFERANCES

[1] Saad, G. R.; Morsi, R. E.; Mohammady, S. Z.; Elsabee, M. Z. J. Polym Res. 2008 15, 115–123. [2] Brouwer, H. d.; Schellekens, M. A. J.; Klumperman, B.; Monteiro, M. J.; German, A. L. J. Polym. Sci., Part A: Polym. Chem. 2000, 38, 3596–3603 [3] Edgren, D.; Wong, P. S. L.; Theeuwes, F. US pat 4587117 1986. [4]Guha, S. K. US pat 5488075 1996. [5]Bellettini, A.G. Bellettini, R.J. US pat 6210653 2001. [6] Metral, G.; Wentland, J.; Thomann, Y. and Tiler, J.C., Macromolecular Rappid Communication, 26 (2005) 1330. [7] Soeda, Y.; Okamoto, T.; Toshima, K. and Matsumura, S., Enzymatic Ring-Opening Polymerization of Oxiranes and Dicarboxylic Anhydrides, Macromolecular Bioscience, 2 (2002) 429. [8] Jaimes, C. ; Dobreva-Schue, R. ; Giani-Beaune, O. ; Schue, F. ; Amass, W. and Amass, A., Ring-opening homopolymerization and copolymerization of lactones. Part 2. Enzymatic degradability of poly(β-hydroxybutyrate) stereoisomers and copolymers of β-butyrolactone with ε-caprolactone and δ-valerolactone, Polymer International, 48 (1999) 23-32. [9] Kobayashi, S., Enzymatic Ring-Opening Polymerization of Lactones by Lipase Catalyst: Mechanistic Aspects, Macromolecular Symposium, 240 (2006) 178-185. [10] Arcana, M. ; Giani-Beaune, O. ; Schue, F. ; Amass, W. and Amass, A., Ring-opening copolymerization of racemic β-butyrolactone with ε-caprolactone and δ -valerolactone by distannoxane derivative catalysts: study of the enzymatic degradation in aerobic media of obtained copolymers, Polymer International, 51 (2002) 859-866. [11] He, F. ; Zhuo, R.X. ; Liu, L.J. ; Jin, D.B. ; Feng, J. and Wang, X.L., Immobilized lipase on porous silica beads: preparation and application for enzymatic ring-opening polymerization of cyclic phosphate, Reactive and Functional Polymers, 47 (2001) 153-158. [12] Varma, K.I. ; Albertsson, A.C. ; Rajkhowa, R. and Srivastava, R.K., Enzym catalyzed synthesis of polyesters, Progress in Polymer Science, 30 (2005) 949-981. [13] Kobayashi, S., Enzymatic polymerization: A new method of polymer synthesis, Journal of Polymer Science Part A: Polymer Chemistry, 37 (1999) 3041-3056. [14] Singha, A. and Kaplan D.L., Enzyme-based vinyl polymerization, Journal of Polymers and the Environment, 10 (2002) 85-91. [15]Tsijumoto, T. ; Uyama, H. and Kobayashi, S., Polymerization of vinyl monomers using oxidase catalysts, Macromolecular Bioscience, 1 (2001) 228-232.

CONCLUSION

Synthesis of MA-St copolymer via enzymatic method was achieved. This was evidenced by ATR-FTIR spectroscopy. The enzyme produced copolymer had some specific physical features such as better thermal stability, single step thermal degradation, and has better solvent resistance. Its surface properties, reflecting a much denser arrangement of the chains were also different. In comparison, the two synthesis method, the enzymatic way has milder reaction conditions and do not require solvent for precipitation. From this perspective it can be said, the enzymatic synthesis of MA-St is more eco-friendly method than the chemical way. [16] Marx, K.A. ; Alva, K.S. and Sarma, R., Self-assembled micron-scale fibre structures are formed by amphiphilic decyl ester derivatives of the D- and L-tyrosine amino acids prior to and following enzymatic ring polymerization, Materials Science and Engineering, C11 (2000) 155-163. [17 Shan, J. ; Han, L. ; Bai, F. and Cao, S., Enzymatic polymerization of aniline and phenol derivatives catalyzed by horseradish peroxidase in dioxane(II), Polymers for Advanced Technologies, 14 (2003) 330-336. [18] Kobayashi, S. and Uyama, H., In vitro polyester synthesis via enzymatic polymerization, Current Organic Chemistry, 6 (2002) 209-222. [19] Kobayashi, S. ; Uyama, H. and Kimura, S., Enzymatic polymerization, Chemical Reviews, 101 (2001) 3793-3818. [20] Nabid, M.R. and Entezami, A.A., Comparative study on the enzymatic polymerization of N-substituted aniline derivatives, Polymers for Advanced Technologies, 16 (2005) 305-309. [21] Oguchi, T. ; Tawaki, S.I. ; Uyama, H. and Kobayashi, S., Soluble polyphenol, Macromolecular Rappid Communication, 20 (1999) 401-403. [22] Oguchi, T. ; Tawaki, S.I. ; Uyama, H. and Kobayashi, S., Enzymatic synthesis of soluble polyphenol, Bulletin of the Chemical Society of Japan, 73 (2000) 1389-1396. [23] Uyama, H. and Kobayashi, S., Enzyme-catalyzed polymerization to functional polymers, Journal of Molecular Catalysis B: Enzymatic 117 (2002) 19–20. [24] Liang, G.; Meng, J. and Zhao L., Synthesis of styrene–maleic anhydride random copolymer and its compatibilization to poly(2,6-dimethyl-1,4-phenylene ether)/brominated epoxy resin, Polymer International, 52 (2003) 966–972.


Kinetics of Zn (II) Ions Adsorption onto Chitin

Nilüfer Nacar Koçer, Gülşad Uslu, Arzu Y. DURSUN, and Barbaros DURMUŞ

Department of Environmental Engineering, Firat University, 23100 Elazig, Turkey *e-mail corresponding author: [email protected]

Keywords: Adsorption, Zn (II) ion, chitin, kinetic.

ABSRACT

In the present study, temperature effects and

kinetics of Zn (II) adsorption onto chitin were investigated. The pseudo-first and second order kinetic models were applied to the data. A series of contact time experiments was carried out with constant initial Zn (II) ion concentration of 100 mg/L at 20, 30 and 40 oC. The results showed that the pseudo-second order kinetic model provided a good correlation for the adsorption of Zn (II) onto chitin.

1. INTRODUCTION

Heavy metal contamination exists in aqueous waste streams of many industries such as metal plating, mining, metallurgy, pigment and ceramic industries. The disposal of industrial effluents containing heavy metals into natural water systems is a cause of serious environmental concern [1-3]. One of the metals released to the environment from a number of sources is zinc. Various technologies have been developed over the years to remove toxic metal ions from water [4]. The most important technologies include filtration, chemical precipitation, ion exchange, adsorption and membrane systems [4-6]. Though these treatments are adequate for the treatment of medium to high concentration solutions, there is still a need for the development of new materials/processes for the treatment of dilute solutions, including the use of low cost materials at biological origin for the sorption of heavy metals from dilute solutions [7,8].

The adsorption process is one of the most efficient methods of removing heavy metal ions from wastewater. The adsorption process provides an attractive alternative treatment, especially if the adsorbent is inexpensive and readily available [9]. Recently, considerable attention has been directed forwards low cost, naturally occurring adsorbents.

Chitin is a natural polysaccharide found

particularly in the shells of crustaceans such as crap and shrimp, the cuticles of insects, and the cells walls of fungi [9-11]. It is the second most abundant polysaccharide after cellulose and renewable natural polymer. Chitin is substantially composed of 2–

acetamido-2 deoxy–D–glukopyranose (N acetly–D –

glucosamine) units linked by – (1– 4) linkage. It carried one linear amino group per glucose ring and exhibits metal ion uptake. Recently, chitin has been widely used as adsorbent in adsorption studies. However much less is known about the adsorption equilibrium, kinetics and thermodynamics of heavy metal on to chitin.

In the present study, Zn (II) adsorption capacity

of chitin was investigated as a function of temperature in a batch system. The experimental data were also analyzed using pseudo first and second order kinetic models and kinetic constants were calculated depending on temperature.

1.1. Kinetic Modelling

Kinetic models are used to examine the rate of the adsorption process and potential rate controlling step i.e. mass transfer or chemical reaction. The capability of pseudo-first order and pseudo-second order kinetic models were examined in this study.

The pseudo-first order equation of Lagergren is

generally expressed as follows [12] : dq/dt= k1(qeq-q) (3)


Where k1 is the rate constant of pseudo-first order sorption (min-1). Integrating this equation for boundary conditions:

t=0 to t and q=0 to qeq gives log (qeq-q)=log(qeq)-(k1/2.303)t (4) A plot of log (qeq-q) against of t should give a

linear relationship with the slope of K1/2.303 and intercept of (log qeq)

The pseudo-second order kinetic rate equation is

expressed as [13]. (Ho and. McKay, 1999): dq/dt= k2(qeq-q)2

(5)

Where k2 is the rate constant of pseudo-second order sorption (g mg-1 min-1). For the same boundary conditions the integrated form of Equation (5) becomes

t/q=(1/k2q

2eq)+(1/qeq)t (6)

The second order rate constant can be

determined from the intercept of the linearized pseudo-second order rate equation.

2. MATERIALS and METHODS

2.1. Adsorbent

Chitin from crushed crub shells (Sigma Chemicals Co.) was used in this study. It was sieved to separate the material into discrete particle size ranges. Previous studies showed that 147-300 µm particle sizes could be chosen as suitable size for adsorption experiments.

2.2. Chemicals

Metal ions solution was prepared by diluting 1 g /L of stock metal ion solution, which was obtained by dissolving a weight quantity of sulfate salts of the metal (Merck). The pH of the each solution was adjusted to the required value with dilute or concentrated H2SO4 and NaOH solutions before mixing with the adsorbent. As negligible changes in the final equilibrium pH were observed, the uptake pH was assumed constant during the experiments.

2.3. Adsorption Experiment

This method involved agitating (150 rpm) 250 cm3

Erlenmeyer flasks containing 0.1 g chitin and 100 cm3 of Zn (II) ion at desired concentration, temperature and pH. All the final solutions contained a fixed concentration of adsorbent. The floods were cogitated on a shake at a 150 rpm constant shaking rate for 24 h. Samples 5 cm3 were taken at predetermined time intervals for the residual metal ion concentrations in the solutions.

Before analysis, samples were filtered and supernatant fluid analyzed for the remaining Zinc (II) ion. All the experiments were carried out at least twice. Values used in the calculation were arithmetic averages of the experimental data. The residual Zn (II) ions in the adsorption media were determined by using an atomic adsorption spectrophotometer (UNICAM 929).

3. RESULTS AND DISCUSSION

Adsorption studies can be affected by

environmental conditions such as initial pH, temperature, initial metal ion concentration. In this study, the adsorption of Zn (II) on chitin was investigated as a function of temperature. The kinetic results is given as units of adsorbed metal ion concentration at equilibrium result (Cad,eq; mg/L), adsorbed metal ion quantity per gram at chitin and unabsorbed metal ion concentration in solution at equilibrium, respectively (qeq; mg g-1,Ceq; mg/L) and adsorption yield (Ad % = 100*(Co-Ceq)/Co).

3.1. Effect of temperature on Zn (II) ion adsorption

The effect of temperature on Zn (II) uptake capacity of chitin was studied at 100 mg l-1 initial metal ion concentration and variation of equilibrium uptake with temperature was given in Figure 1.

Figure 1. The effect of initial temperature on the Zn (II) ion adsorption (Co= 100 mg /L, pH= 4.5, X: 1.0 g/L, agitation rate= 150 rpm).

4

5

6

7

8

10 20 30 40 50

qeq

(mg

g-1)

T, oC


The equilibrium uptake of Zn (II) ion to chitin was affected by temperature and increased with increasing temperature up to 40oC. The optimum adsorption temperature for Zn (II) ion was determined to be 40 oC. Result given in Figure 2 clearly showed that, initial sorption of Zn (II) ion occurred very rapidly and reached equilibrium in 100 min for 100 mg /L initial Zn (II) concentrations at all temperatures studied. The variation of unabsorbed Zn (II) concentration in solution was negligible after 100 min of contact time. The maximum adsorption yields were determined as 10.10 %; 12.50 % and 18.90 % at 10 mg /L initial Zn ( II ) ion concentration for 20, 30 and 40 oC, respectively (Table 1). The adsorption yields showed a decreasing trend as the initial Zn (II) ion concentration was increasing[14].

Figure 2. The adsorption curves of Zn (II) ion. (Co=100 mg/L, pH= 4.5, X: 1.0 g /L, agitation rate= 150 rpm). Table 1. The equilibrium uptake capacities and adsorption yields obtained at different initial concentrations and temperatures

3.5. Determination of kinetic constants

In order to analyze the adsorption kinetics of Zn (II), the saturation type kinetic model was applied to the data at different temperatures from 20 to 40 oC. A series of contact time experiments was carried out with constant initial Zn (II) ion concentration of 100 mg /L at 20, 30 and 40 oC. The pseudo-first and second order kinetic models were applied to the data.

The results showed that, the correlation

coefficients for the first order kinetic model were very low (Table 2).

Tablo 2. Change of the pseudo- first and second order reaction rate constants with temperature

T, oC

qeq,exp

(mg g-1)

First order kinetic model

k1

(min -1) qeq,cal

(mg g-1)

R2

20 5,17 0,035 1,939 0,9371 30 6,12 0,035 3,296 0,8795 40 6,93 0,036 4,450 0,8415

T, oC

qeq,exp

(mg g-1)

Seconder order kinetic model

k2

(g mg-1

min-1)

qeq,cal

(mg g-1)

R2

20 5,17 0,048 5,245 0,999 30 6,12 0,046 6,180 0,999 40 6,93 0,028 7,020 0,999

The theoretical qeq values found from this model did not give reasonable values; so pseudo-first order model did not describe the adsorption results of Zn (II) ion concentration onto chitin. Table 2 shows the results of the pseudo-second order model.

The values of correlation coefficient were very

high and the theoretical qeq values were closer to the experimental qeq values. In the view of these results, it can be said that the pseudo-second order kinetic model provided a good correlation for the adsorption of Zn (II) onto chitin in contrast to the pseudo-first order model.

012345678

0 50 100 150 200 250 300

q (m

g g-

1)

t (min)

20 oC30 oC40 oC

Co

(mg /L)

20 C

30 C 40 C

qeq

(mg g-1)

% Ad.

qeq

(mg g-1)

% Ad.

qeq

(mg g-1)

%

Ad.

10

1.01 10.10

1.25

12.50

1.89

18.90

25 1.40 5.60 1. 93 7.72 4.06

16.24

50 2.75 5.50 3.19 6.38 5.25

10.50

75 4.01 5.35 4.55 6.16 6.28 8.37

100 5.17 5.17 6.12 6.12 6.93 6.93

150 6.25 4.16 6.98 4.65 7.75 5.17

300 7.32 2.44 7.61 2.54 8.21 2.74


CONCLUSION

In this study, temperature effects and kinetics of Zn (II) adsorption onto chitin were investigated. It was seen that, adsorption increased with temperature up to 40 oC and initial Zn (II) ion concentration up to 300 g /L. The pseudo first-order and pseudo second-order kinetic models were used to analyze data obtained for Zn (II) ion onto chitin. The results indicate that the pseudo–second order equation provided the better correlation for the adsorption data.

REFERENCES

1 Dursun, A. Y, (2006). A comparative study on determination of the equilibrium, kinetic and Thermodynamic parameters of adsorption of copper(II) and lead(II) ions onto pretreated Aspergillus niger, Biochem. Eng. J. 28, 187–195. 2 Nurbaş Nourbakhsh, M. Kiliçarslan,S. Ilhan S. and Ozdag, H., (2002) Adsorption of Cr6+, Pb2+ and Cu2+ ions in industrial waste water on Bacillus sp, Chem. Eng. J. 85 (2-3), 351-355. 3 Uslu, G. Tanyol, M., (2006). Equilibrium and Thermodynamic Parameters of Single and Binary mixture Adsorption of Lead (II) and copper (II) ions onto Pseudomonas. putida: effect of temperature, J. Hazard. Mater. B135, 87-93. 4 Pradhan,S., Shukla, S. S., Dorris, K. L., (2005). Removal of nickel from aqueous solutions using crab shells. J. Hazard. Mater. 125 (1-3), 201-204. 5 Yu, B., Zhang,Y., Shukla, A., Shukla, S. S., Dorris, K. L., (2000). The removal of heavy metal from aqueous solutions by sawdust adsorption-removal of copper, J. Hazard. Mater. 80 (1-3), 33-42

6 Dzul Erosa, M. S., Saucedo Medina, T. I., Navarro Mendoza, R., Avila Rodriguez, M., Guibal, E., (2001). Cadmium sorption on chitosan sorbents: kinetic and equilibrium studies. Hydrometallurgy. 61 (3), 157-167.

7 Puranic, P. R., Modak, J. M. Paknikar, K. M. (1999). A comparative study of the mass transfer kinetics of metal adsorption by microbial biomass, Hydrometallurgy. 52, 189-197.

8 Bhattacharya, A. K., Venkobacher, C. (1984). Removal of cadmium (II) by low cost adsorbents, J. Environ. Eng. 110, 110-122. 9 Akkaya, G. Uzun, I., Guzel, F., (2007). Kinetics of the adsorption of reactive dyes by chitin, Dyes and Pigm. 73, 168-177. 9 Dursun, A.Y., Kalaycı, C. S. (2005). Equilibrium, kinetic and

thermodynamic studies on the adsorption of phenol onto chitin, J. Hazard. Mater. B123, 151–157.

10 Nassar, M. M., Magdy, Y. H., (1997). Removal of different basic dyes from aqueous solutions by adsorption on palm-fruit bunch particles, Chem. Eng. J. 66:223. 12 Lagergren, S., 1998. Zur theorie der sogenannten adsorption geloster stoffe, Kungliga Svenska Vetenkapsakademiens, handlingar 24, 1–39.

13 Ho, Y.S., McKay, G., (1999). Pseudo-second-order model for sorption processes, Process Biochem. 34, 451–465. 14 Kocer, N. Nacar; Uslu, G.; Cuci, Y., The Adsorption of Zn (II) Ions onto Chitin: Determination of Equilibrium, Kinetic and Thermodynamic Parameters, Adsorption Science & Technology, Volume: 26 Issue: 5 Pages: 333-344 Published: 2008.

31 2nd ITWCCST – August 26-30, 2016 - Skopje, Macedonia.

Removal of Zn (II) Ions from Aqueous Solution by Chitin

Arzu Y. DURSUN, Nilüfer NACAR KOÇER, Gülşad USLU and Neslihan ÇANAKÇI DURMUŞ

Department of Environmental Engineering, Firat University, 23100 Elazig, Turkey *e-mail corresponding author:[email protected]

Keywords: Adsorption, Zn (II) ion, chitin, equilibrium.

ABSTRACT

The adsorption of Zinc (II) from aqueous solutions

onto chitin was investigated as a function of initial pH and initial metal ion concentration. The highest zinc adsorption capacity was determined as 8.21 mg g-1 for 300 mg l-1 initial Zn (II) ion concentration at pH = 4.5 and 40 oC. The Freundlich and Langmuir adsorption models were used for the mathematical description of the adsorption equilibrium and isotherm constants were evaluated at different temperatures. Adsorption data were well described by the Langmuir Model, although they could be modeled by Freundlich Model.

1. INTRODUCTION

The presence of heavy metals in industrial

wastewaters presents a major environmental and ecological hazard. Heavy metals such as copper, cadmium, zinc and lead have been widely used in industry. They are regarded as the potentially toxic metals with cumulative toxicity to humans and various aquatic organisms [1,2]. Several methods are available for removing heavy metals from waste streams, including chemical precipitation, membrane filtration and ion exchange [3,4]. These traditional methods are often ineffective and/or very expensive when used for the removal of heavy metal ions when present at very low concentrations.

Adsorption on the activated carbon is still one of

the much used methods among them. However, its high initial cost and the need for a costly regeneration system make it less economically viable as an adsorbent. Taking these criteria into consideration, the search for a low cost and easily available adsorbent has led many investigators to search more economic and efficient techniques to use agricultural waste origin, along with industrial by-products as adsorbents. These novel

adsorbents include a wide range of materials ranging from by-products derived from agricultural, industrial and fishery wastes (peanut skins, wool, sugar cane bagasse, tea leaves, coffee powder, wool, rice straw, chitin, etc.) to microbial biomass[5,6]. Chitin is the second most abundant and renewable natural polymer. It is found in the exoskeletons of crabs and other arthropods and in the cell walls of some fungi[7]. Chitin is also a waste product of the crab meat canning industry and it can be extracted in large quantities from crab and shrimp shells. Chitin carries one linear amino group per glucose ring and exhibits metal ion uptake and. much less is known about the adsorption of Zn (II) onto chitin.

The aim of this study was to investigate the Zn (II)

adsorption characteristics of chitin taking into account equilibrium aspects. The adsorption of Zinc (II) from aqueous solutions onto chitin was investigated as a function of initial pH and initial metal ion concentration. The Freundlich and Langmuir adsorption models were used for the mathematical description of the adsorption equilibrium and isotherm constants were evaluated at different temperatures.

1.1. Adsorption equilibrium

Equilibrium study on adsorption has provided information on the capacity of the adsorbent. Also, an adsorption isotherm is characterised by certain constant values that express the surface properties and affinity of the adsorbent and can also be used to compare the adsorptive capacity of the adsorbent for different pollutants. Among the available adsorption equilibrium isotherm models, the most generalized model is a correlative equation proposed by Langmuir[7]. In obtaining the Langmuir isotherm equation,


several aspects of the adsorption system were presupposed in the derivation. The most important assumptions are; (i) All the surface of the catalyst has the same activity for adsorption, (ii) There is no interaction adsorbed molecules and all the adsorption occurs by the same mechanism, (iii) The extent of adsorption is less than one complete monomolecular layer on the surface. The Langmuir equation is given by Eq. (1).

eqb

eqbeq CK

CKqq

1max (1).

where qeq is the metal ion adsorbed on chitin at equilibrium, Ceq is the equilibrium concentration in the solution, qmax is the adsorption capacity and Kb is the adsorption equilibrium constant related to energy of adsorption.

The Freundlich model is however an empirical

equation based on adsorption on a heterogeneous surface, suggesting that binding sites are not equivalent and/or independent. Freundlich equation is expressed as

[8];

qeq = KF n

eqC /1 (2). (2)

where KF is an indicator of the adsorption capacity and n is an indicator of the adsorption intensity.

2. MATERIALS and METHODS

Chitin from crushed crub shells (Sigma

Chemicals Co.) was used in this study. It was sieved (147-300 μm) to separate the material into discrete

particle size ranges. Metal ions solution was prepared by diluting 1

g/L of stock metal ion solution, which was obtained by dissolving a weight quantity of sulfate salts of the metal (Merck). The pH of the each solution was adjusted to the required value with dilute or concentrated H2SO4 and NaOH solutions before mixing with the adsorbent. As negligible changes in the final equilibrium pH were observed, the uptake pH was assumed constant during the experiments.

2.1. Adsorption studies

This method involved agitating (150 rpm) 250 cm3 Erlenmeyer flasks containing 0.1 g chitin and 100 cm3 of metal ion solutions at desired concentration, temperature and pH. Samples (5 ml) were taken before mixing the chitin and metal ion solution and at pre-determined time intervals for determining the residual Zn (II) ions concentration in the medium. The flasks were agitated on a shaker at a 150 rpm constant shaking rate for 24 hours. Before analysis, samples were filtered and supernatant fluid analyzed for the remaining metal ion. The residual Zn (II) ions in the adsorption media were determined by using an atomic adsorption spectrophotometer (UNICAM 929).

3. RESULTS AND DISCUSSION

3.1. Effect of initial pH

The effect of initial pH on Zn (II) ions uptake

capacity of chitin was investigated between pH 2-5 at 100 mg /L initial metal concentration and the variation of equilibrium uptake with initial pH was given in Figure 1. Maximum adsorption capacities were obtained as 6.93 mg g-1 at pH 4.5 for Zn (II) ion. The pH primary affects the degree of ionization of the metal ion and the surface properties of chitin. This may be due to the formation of soluble hydroxyl complexes. The onset of metal hydrolysis and precipitation begin at pH > 5 [9].

The hydrolysis of metal ions occurs by the

replacement of metal ligands in the inner co-ordination sphere with the hydroxyl group. This replacement occurs after the removal of the outer hydration sphere of metal ions. Adsorption may not be related directly to the hydrolysis of the metal ion, but instead, outer hydration sphere that precede hydrolysis [10].The hydrogen ion concentration increases if pH is low (below 3), thus, competitive adsorptions between H+ and Zn (II) result in low adsorption efficiency of Zn ion [10, 11].


Figure 1. The effect of pH on the Zn (II) ion adsorption (Co= 100 mg /L, T= 40 oC, X: 1.0 g /L, agitation rate= 150 rpm). 3.3. Effect of initial CRR 195 concentration on temperature depended adsorption

The effect of initial Zn (II) ion concentration on

the sorption capacity of chitin was investigated at different temperatures, pH 4.5 for Zn (II). As a rule, Table 1. The equilibrium uptake capacities and adsorption yields obtained at different initial concentrations and temperatures

increasing the initial metal concentration results in an increase in the biosorption capacity because the initial metal concentration provides a driving force to overcome mass transfer resistances between the biosorbent and biosorption medium. At lower concentrations, all sorbet ions present in the adsorption medium could interest with the binding sites so higher adsorption yields were obtained. At higher concentrations, lower adsorption yields were observed because of the saturation of the adsorption rites. Table 1 shows that, the equilibrium sorption capacity of the adsorbent increased with increasing initial Zn (II) ion concentration up to 300 mg /L because the initial adsorbent concentration provided an important driving force to overcome all mass transfer resistance. The increases of loading capacity of chitin with increasing initial Zn (II) concentration may also be due to higher interaction between Zn (II) ion and chitin. Thus a higher initial Zn (II) concentration will enhance the adsorption process. 8.21 mg Zn (II) g-1 of chitin was adsorbed at equilibrium at 40oC. The adsorption of Zn (II) ions by chitin may involve not only physical but also chemical sorption. This effect may be due to the fact that at higher temperatures an increase in active sites occurs due to bond rupture [11].

3.4. Determination of equilibrium model constants in batch system

The Freundlich and Langmuir adsorption constants evaluated from the isotherm at different temperatures with the correlation coefficients are presented in Table 2. The adsorption capacity of chitin increased with increasing the temperature and maximum qmax values were determined as 9.56 at 40oC for Zn (II) ions. A high Kb value indicates the affinity for binding of metal ions.

4

5

6

7

8

1 3 5 7

qeq

(mg

g-1)

pH

Co

(mg L-1)

20 C

30 C 40 C

qeq

(mg g-1)

% Ad.

qeq

(mg g-1)

% Ad.

qeq

(mg g-1)

%

Ad.

10

1.01 10.10

1.25

12.50

1.89

18.90

25 1.40 5.60 1. 93 7.72 4.06

16.24

50 2.75 5.50 3.19 6.38 5.25

10.50

75 4.01 5.35 4.55 6.16 6.28 8.37

100 5.17 5.17 6.12 6.12 6.93 6.93

150 6.25 4.16 6.98 4.65 7.75 5.17

300 7.32 2.44 7.61 2.54 8.21 2.74


Table 2. Isotherms constants for Zn (II) ion adsorbed on chitin

In view of the results presented in Table 2, the isotherms appeared to follow the Langmuir model more closely than the Freundlich model at all the temperatures studied.

CONCLUSION

In this study, the ability of chitin to adsorb Zn (II)

ions was investigated in a batch system. It was seen that initial pH, temperature and initial metal ion concentration highly affected the adsorption capacity of the sorbent. The optimum pH value was determined to be 4.5. It was found that Zn (II) ion adsorption increased with temperature up to 40 oC and initial Zn (II) ion concentration up to 300 mg/L. The equilibrium of adsorption of Zn (II) ions on to the sorbent was tested using Langmuir Model and Freundlich Models. The result obtained showed that the adsorption fitted the Langmuir Model in the studied concentration range at all the temperatures studied

REFERENCES 1 Patterson J.W., 1977, Wastewater Treatment Technology.. Ann Arbor Science Publishers inc., USA. 2Prosi, F. Heavy metals in aquatic organisms in metal pollution in the aquatic environment. New York: Springer, 1981, 285-289. 3Weber, WJ. Physicochemical processes for water quality control. USA: Wiley-Interscience, 1972. 4Lee, S.H.; Yang, J.W. Separ Sci Technol. 1997, 32,1371-/87. 5Bhattacharya, A. K.; Venkobachar, C. J. Environ. Eng. ASCE. 1984,110, 110-122. 6El-Geundi, M.S. Adsorpt. Sci. Technol. 1997, 15, 777-787. 7Berkeley, R.C.W. Chitin, Chitosan and Their Degradative Enzymes, In Microbial Polysaccharides, eds. R.C.W. Berkeley, C.W. Gooday and D.C. Elwood, Academic Press. New York: 1979, 205-236. 8 Smith, J. M., 1981.Chemical Eng. Kinetics (3rd Ed) McGraw-Hill, Singapore. 9Baes, G.B.; Mesmer, R.E. Hydrolysis of Cations, John Wiley and Sons, New York: 1976. 10Amuda, O.S.; Giwa, A.A. and Bello, I.A. Biochem. Eng. J. 2007, 36, 174-181. 11Kocer, N.N.; Uslu, G.; Cuci, Y. Adsorption Science & Technology 2008, 26, 333-344.

T (oC)

Langmuir Model Freundlich Model

qmax

(mg g-1)

Kb

R2 KF n R2

20 4.65 0.027 0.98 0.219 1.427 0.97

30 6.08 0.028 0.99 0.269 1.506 0.97

40 9.56 0.030 0.99 0.711 1. 930 0.98


Estimation of Blast for VCE: A Case Study

Merve Ercan KALKAN, Dicle ÇELİK, Kadriye OKTOR*

1Department of Chemical Engineering, Kocaeli University, TR-41380 Kocaeli, Turkey

2Department of Environmental Engineering, Kocaeli University, TR-41380 Kocaeli, Turkey

*[email protected]

Vapor cloud explosion, blast, major accident, peak overpressure

INTRODUCTION

Production, usage, storage and transportation of

chemicals are inevitable results of developing technology and industrialization. Although living standards are rising, inappropriate and uncontrolled chemical processes still cause loss of containment, life, prestige and environmental damage [1]. These events mostly contain at least one (or more) of fire, explosion and toxic release. Accidental explosions occur because of very fast energy release and can produce large quantities of expanding gas [2]. The explosions, which occur at process plants, can be classified as explosions in chemical reactors, explosions of high-pressure gases inside plant, explosions of flammable gas-air mixtures inside plant and in buildings, boiling liquid expanding vapor explosions (BLEVE) and vapor cloud explosions (VCE) [3]. VCE is defined by the AIChE as an explosion resulting from the ignition of a cloud of flammable vapor, gas or mist in which flame speeds accelerate to sufficiently high velocities to produce significant overpressure [4]. After Flixborough disaster in 1974, which resulted in a VCE and caused 28 fatalities because of cyclohexane release, scientists make efforts to analyze and cope with the effects of VCEs. As an accident type, VCE was found one of the most severe threats to industrial plants where large amounts of flammable materials are stored or processed [5-10]. VCE occurs following these steps:

1. Sudden release of a large quantity of flammable vapor

2. Dispersion of the vapor through the plant site while mixing with air

3. Ignition of the resulting vapor cloud

Many parameters affect the VCE behavior such as quantity of material released, fraction of material

vaporized, probability of ignition of the cloud distance travelled by the cloud prior to ignition, time delay before ignition of cloud, probability of explosion rather than fire, existence of a threshold quantity of material, efficiency of explosion and location of ignition source with respect to release. There have been different methods for estimating effects of VCE. TNT Equivalency Method, Multi-Energy Method and Baker-Strehlow-Tang method are presented in literature for this purpose.

“TNT equivalency” method which is based on

equivalency between the flammable material and TNT, is a common approach and determines the damage caused by a certain explosion through estimating the mass of TNT that would generate the same degree of damage [2,10].

WTNT=η (M ∆HC/∆HTNT) (1) where M is the mass of fuel in the cloud (kg), ∆Hc is the lower heat of combustion of the fuel (kJ kg-1), η is the explosion yield factor and ∆HTNT is the blast energy of TNT (4680 kJ kg-1).

The peak overpressure can also be estimated from the scaled distance dn, by use of the following expressions:

dn=d/WTNT

1/3 (2) ∆P/P0=[(1/dn)+(4/dn

2)+(12/ dn3)] (3)

For a certain equivalent mass of TNT, the side-

on peak overpressure (∆P) and the impulse at various distances can be derived by graphical interpolation with reference to characteristic curves from Figure 1 [2].

Multi-Energy Method considers the size, shape

and nature of the flammable cloud that could be


partially confined or obstructed. Cloud size, congested areas and their free volumes, source strength, location and energy of each area, and combustion energy for scaled distance should be taken into account. Combustion energy scaled distance (R) could be calculated from: R=d/(E/Po)

1/3 (4) where E (J) is the explosion energy and P0 is 101,325 Pa. E can be calculated if mass (M) and heat of combustion (∆HC) are known. Multi Energy method blast charts involve 10 curves form low strength (1) to detonation (10).

Figure 1. Side-on peak overpressure for TNT explosion [2]

The peak overpressure (∆P) for the Multi Energy Method is calculated with the equation of: ∆P= ∆Ps.P0 (5)

where ∆Ps is dimensionless side-on peak overpressure and can be obtained from Figure 2.

Figure 2. Multi Energy method blast chart [2]

Baker-Strehlow-Tang (BST) method considers the effects of congested zones to the generation of blast, like Multi Energy Method. Both methods use the same approach to estimate the explosion energy (E), based on an average stoichiometric fuel-air mixture. BST methodology contains a flame speed table and a family of blast curves for overpressure and impulse at flame Mach numbers. The appropriate Mach number, Mf, for different situations can be taken from the specific tables [2,11–13]. These tables contain Mach numbers according to flame expansion (2D, 2.5D or 3D), reactivity (low, medium and high) and congestion (low, medium and high).

Figure3. BST method dimensionless peak side-on overpressure vs combustion energy scaled distance for different Mf numbers [2]


In this study, effects of different scaled

hydrocarbon release scenarios were evaluated in terms of peak overpressure using three different methods mentioned above. Scenario could be detailed by this way: A chemical production factory has heptane storage tank with a volume of 20000m3. During a night shift, a valve fails and a leakage starts from a full tank emptying 2/3 of it. The vapor catches a fire and causes a VCE. For the calculations, mass of the heptane in the cloud is assumed 10,000 kg, heat of combustion for heptane is taken 47,711 kJ/kg and heat of combustion for TNT is taken 4,680 kJ/kg [2,10].


The effects of blast the given VCE scenario for five different distances (100, 250, 500, 750 and 1000m) are calculated by applying mentioned three methods and the results are tabulated. According to literature, explosion yield factors vary from 1% to 10 %. In table 1, overpressure is calculated for different explosion yields. It can be seen that the peak overpressure values varies from 1 kPa to 53 kPa. Table.1 Overpressure results for TNT method in kPa Explosion Yield Factor (η)

Distance (m) 100 250 500 750 1000

0.01 15.539 4.814 2.213 1.435 1.062 0.03 26.959 7.486 3.312 2.121 1.559 0.05 35.631 9.290 4.016 2.552 1.869 0.07 43.197 10.759 4.570 2.888 2.109 0.1 53.409 12.627 5.254 3.296 3.296 Table 2 shows the calculated overpressure results by using Multi-Energy method. Here, explosion strengths are taken at four different levels: 1 as weakest, 5 as mid, 7 and 9 are as for severe explosion simulation. Table.2 Overpressure results for Multi-Energy method in kPa Explosion Strength

Distance (m) 100 250 500 750 1000

1 1.013 0.405 0.223 0.162 0.122 5 30.398 10.132 4.053 2.736 2.026 7 83.087 40.53 10.132 6.586 4.256 9 151.99 40.53 10.132 6.586 4.256 For BST method, a Mach number should be determined with respect to the flame expansion, reactivity and congestion. For the studied scenario flame expansion is thought to be 3D since vapour cloud has no confining plane surface. Also, reactivity is advised to be considered as medium by Baker et al. [14] for hydrocarbons except methane. Lastly, congestion is

considered medium, because the heptane tank is obstructing the explosion somehow. By using flame speed Mach numbers table [2], the Mach number for the scenario is found 0.44. Calculated overpressure values for five different distances can be seen in Table 3. Table.3 Overpressure results for BST method in kPa

Mach Number Distance (m)

100 250 500 750 1000 0.44 18.238 9.119 4.053 2.129 1.925

It is difficult to compare the findings of these methods, as they are products of different hypotheses. Although TNT method is criticized for not taking into account the obstacles and being uncertain about explosion yield, it is widely accepted because of its easy algorithm. When it comes to Multi Energy and BST methods both contain assumptions for using specific charts.

For TNT explosion yield 0.05 and Multi Energy explosion strength 5, both methods give similar results whereas the BST method complies with those results at medium and long distances.

CONCLUSION

The Flixborough accident of 1974, the Texas

City accident of 2005, the Phillips 66 accident of 1989, and the Buncefield incident of 2005 show that VCE is one of the most severe threats to chemical process industries and scientists make efforts to analyze and cope with the effects of VCEs [15]. Therefore, estimation results of a VCE ahead of any probable accident and taking precautions against are important for process safety management. This need leads many simple to advanced computational methods. TNT Equivalency Method, Multi-Energy Method and Baker-Strehlow-Tang Method are easier to apply and hence practical; however, their drawback is these calculations depend on many assumptions.

In this study, effects of different scaled

hydrocarbon release scenarios were evaluated in terms of peak overpressure using those mentioned methods. For the medium sized VCEs, all three methods give similar results. Nevertheless, when the distances are too close or too far from the source; or, explosion strength and yield is too high or too low; it is possible to say that the results differ much. End users’ expectation, usage

area and precision are thought to be limiting criteria for method selection.


REFERENCES 1Ercan Kalkan, M.; Deniz, V.; Dow Chemical Exposure Index Methodology, International Congress on Occupational Safety and Security, 2016. 2Casal, J.; Evaluation of the Effects and Consequences of Major Accidents in Industrial Plants, First Edition, Elsevier, 2008, 119-137. 3Mannan, S.; Lees’ Process Safety Essentials Hazard Identification, Assessment and Control, First Edition, Elsevier, 2014, 283-288. 4AIChE, VCE, http://www.aiche.org/ccps/resources/glossary/process-safety-glossary/vapor-cloud-explosion-vce, accessed 01.10.2016. 5Venart, J. E. S.; Flixborough: The Explosion and Its Aftermath. Safety and Environmental Protection, 2004, 82(b2): 105-127. 6Raman R.; Grillo P.; Process Safety and Environmental Protection, 2005, 83(B4): 298–306. 7Alonso F D.; Ferradas E G.; Perez F. F. Z.; Aznar, A. M.; Gimeno, J. R.; Alonso, J. M.; Characteristic overpressure–impulse–distance curves for vapour cloud explosions using the TNO Multi-Energy model. Journal of Hazardous Materials A137, 2006, 734–741. 8Johnson D. M.; Tomlin G. B.; Walker D. G.; Detonations and vapor cloud explosions: Why it matters. Journal of Loss Prevention in the Process Industries 36, 2015, 358-364.

9Ramírez-Marengo C.; Diaz Ovalle C.; Vazquez-Roman C.; Mannan M. S.; A stochastic approach for risk analysis in vapor cloud explosion. Journal of Loss Prevention in the Process Industries 35, 2015, 249-256. 10Crowl D. A.; Louvar J. F.; Chemical Process Safety Fundamentals with Applications, 1990, 181-183. 11Sharma, R.K.;. Gurjar, B.R.; Wate, S. R.; Ghuge, S. P.; Agrawal, R.; Journal of Loss Prevention in the Process Industries 26, 2013, 82-90. 12Yongfu, X.; Worthington, D.; Oke, A.; Correcting The Predictions By Baker-Strehlow-Tang (Bst) Model For The Ground Effect, 2009, Symposium Series No. 155, 318-325. 13Pierorazio, A. J.; Thomas, J. K.; Baker, Q. A.; Ketchum, D. E., An update to the Baker-Strehlow-Tang vapour cloud explosion prediction methodology flame speed table, Process Safety Progress, 2005, 24, 59- 65. 14Baker Q. A.; Process Safety Progress 15, 1996, 106 15Bauwens, C. R.; Dorofeev, S. B.; Effects of the Primary Explosion Site and Bulk Cloud in VCE Prediction: A Comparison with Historical Accidents, Process Safety Progress, 2015, Vol.34, No.2


First-principles Study of Electronic and Dynamic Properties of Co3V

Compound

Nihat ARIKAN*

Ahi Evran ÜniversitesiEğitim Fakültesi, İlköğretim Bölümü, 40100-Kırşehir/TURKEY * [email protected]

Keywords: DFT; band structure; phonon; specific heat capacity

INTRODUCTION

A3B compounds are currently under intense investigations driven by their structural and physical properties. These compounds have interesting mechanical properties, and some of them are the following: i) L12 atomic order are significantly more ductile than these that from D22 order. ii) Its use structural materials for ultra high temperature applications. iii) They have high melting points and good corrosion resistance. Co-based compounds are widely used because of their excellent high temperature mechanical properties. Co-based compounds are also used for various reasons, including their excellent hot corrosion resistance, thermal fatigue resistance and weldability [1]. Co3V compound is binary intermetallic compound with the L12 structure, which belongs to Pm-3m space group. The structural, phase stability, elastic, thermodynamic electronic and cohesive properties of Co3V have been studied by several groups, employing different theoretical and experimental schemes [1-7]. The structural, phase transformation temperatures and partition behaviour of Co3V studied by Omori et al. [1]. The structural, electronic structures, elastic properties and thermodynamic properties of Co3V compound have been investigated using the projector augmented wave (PAW) pseudopotential method, as implemented in the Vienna ab initio Simulation Package (VASP) by Xu et al. [2]. Lin et al. [3, 11] have also studied the electronic structure, cohesive properties, and phase stability of the intermetallic compounds Co3V in their L12, DO19, and DO22 structures using by the self-consistent total-energy linear-muffin tin-orbital method based on the local-density approximation. Nagel et al. [10] measured the difference in the heat capacity of the L12 and hP24 phases of Co3V compound using calorimetry at temperatures from 80 to 320 K. The current work focuses on the theoretical study of the structural and electronic properties of Co3V in the L12 phase, with particular emphasis on phonon properties, by employing the DFT. The phonon properties are necessary for a microscopic understanding of the lattice dynamics. The knowledge of the phonon spectrum plays a significant role in determining various material properties such as phase transition, thermodynamic stability, transport and

thermal properties. The band structure has been obtained by applying the plane-wave pseudopotential method within the generalized gradient approximation (GGA). These results are then used, within a linear-response approach, to calculate the phonon dispersion curves and the density of states.

METHOD

The ab initio calculations have been performed using the Quantum-ESPRESSO program package [12]. We use the generalized gradient approximation (GGA) using the scheme of Perdew–Burke–Ernzerhof (PBE) [13] with a plane wave pseudopotential approach. The electron–ion interaction was described by ultrasoft Vanderbilt pseudopotential [14]. The single-particle functions were expanded in a plane-waves basis set up to the kinetic energies cut off 40 Ry, which is sufficient to fully converge all properties relevance. The electronic charge density was evaluated up to the kinetic energy cut-off 400 Ry. Self-consistent solutions of Khon–Sham equations were obtained by employing a set of 60 k-points within the irreducible part of the Brillouin zone. Integration up to the Fermi surface is done with a smearing technique [15] with the smearing parameter =0.02 Ry. Eight dynamical matrices have been calculated on a 4x4x4 q-point mesh to obtain complete phonon dispersions and vibrational density of states. The dynamical matrices at arbitrary wave vectors were evaluated by using the Fourier deconvolution on this mesh. Specific heat and Debye temperature are calculated at various temperature from the phonon frequencies obtained through the quasi-harmonic model (QHA) [16]. The elastic constants can be obtained by calculating the total energy as a function of volume-conserving strains that break the cubic symmetry. The bulk modulus B, C44, and shear modulus C’ = (C11- C12)/2are calculated from hydrostatic pressure e e = (,,,0,0, 0), tri-axial shear strain e = (0, 0, 0,,,) and volume-conserving orthorhombic strain e = (,, (1 + )-2-1, 0, 0, 0), respectively [17]. Hence, B can be obtained from

∆𝐸

𝑉=

9

2𝐵𝛿2


where V is the volume of unstrained lattice cell, and E is the energy variation as a result of an applied strain with vector e = (e1,e2, -e3, e4,e5,e6). C′can be calculated from

Δ𝐸

𝑉= 6C′δ

2 + 0δ3

The two expressions above yield 𝐶11 = 3𝐵 + 4𝐶 ′ /3 and 𝐶12 = 3𝐵 − 2𝐶 ′ /3, and C44 is given by

Δ𝐸

𝑉=

3

2𝐶44𝛿

2

The details on the calculation of elastic constants have been described in our previous papers [18].


The structural properties of Co3V compound in the L12 phase have been analyzed by DFT calculations. The lattice constants and the pressure derivatives of the bulk modulus have been obtained by fitting the total energy data with the Murnaghan equation of state [19]. The calculated values for a, B, C11, C12, C44, dB/dP, G, and B/G of Co3V have been summarized in Table 1 and are compared to other experimental and other theoretical findings. The lattice constant of my calculated is in good agreement with previous theoretical data [1-3]. The elastic constants are important parameters that describe how a material behaves under stress. In the case of cubic crystals, there are three independent elastic constants (C11, C12, and C44), and the mechanical stability conditions are C11+C12>0, C44>0, and C11–

C12>0 [20]. I have used the formulas and procedures for the calculation of elastic constants and bulk modulus in a previous publication [21]. The calculated elastic constants of Co3V compound are listed in Table 1, together with data available from other calculation for comparison [2]. To the best of our knowledge, no experimental values for the elastic constants of this compound have been appeared in the literature, so our results for L12 phase can serve as a prediction for future investigations. My calculated values of C11, C12 and C44 for Co3V have been found to be smaller than those of Ref. [2] by about 29%, 10%, and, 8.5%, respectively. It is clearly seen from Table 1, that these criteria are verified, so I conclude that Co3V compound is stable in the L12 phase. In order to investigate the mechanical properties of Co3V compound, brittleness and ductility properties have also been studied by using the bulk modulus to shear modulus B/G ratio. According to Pugh [22], B/G ratio is greater than 1.75, so Co3V compound in the L12 phase is brittle. According to figure 1 and figure 2, there is no band gap at the Fermi level. Valance and conduction bands overlap significantly at the Fermi level. The calculated electronic structures clearly show the metallic nature of Co3V. The bands profiles and density of states for this

compound are in good agreement with previous theoretical results [2, 3 and 11]. The character of the band states for Co3V compound has been identified by calculating their total and partial densities of the states (DOS) in figure 2. The results indicate that the predominant contributions of the density of states at the Fermi level come from the Co 3d state for this compound. From the calculated total DOS of Co3V compound, it can be seen that there is one peak above the Fermi level. This peak is centred between 1.5 and 2 eV, which is mainly dominated by the V 3d state. In addition, the total DOS of Co3V contains two peaks below the Fermi level. The characters of these peaks are dominated by the Co 3d states. The general trends of the Co3V electronic band structure are consistent with the earlier work [21, 23, and 24]. The theoretical and experimental data of phonon properties of Co3V in the L12 phase is not yet available. The calculated phonon dispersion curves for Co3V compound along the high-symmetry directions and the phonon density of states (partial and total) are illustrated in Figure 4. As the unit cell of the L12 phase contains four atoms, so there are 12 phonon branches, three acoustical and nine optical. As can be seen from Figure 3, all phonon modes have positive frequencies indicating the dynamical stability of this compound in the L12 phase. For studied compound, the separation between the acoustical and optical branches is not sufficient to create a gap. The low frequency region of the phonon DOS in the L12 phase consists mostly of the contribution of the heavier V atoms for Co3V, while the contribution of lighter Co atoms appears only at the uppermost frequency range above 4 THz. The knowledge of the full phonon spectrum granted by DFPT makes possible the calculation of several important thermo dynamical properties as function of temperature T. Temperature dependence of the constant volume specific heat CV for the Co3V compound in the L12 phase are determined within the quasi-harmonic approximation based on the calculated phonon dispersion relations and depicted in Figure 4. The Cv increases rapidly in the range 0–200 K before it starts to saturate. The calculated specific heat capacity Cv is very close to the Dulong-Petit limit [25] at high temperature, which is commonly satisfied with all solids at high temperatures.

Figure 1 Electronic band structure of Co3V in the L12 phase. The Fermi energy is taken as energy zero.


Table 1. Calculated lattice constants (in Å), bulk modulus (in GPa) and pressure derivative of the bulk modulus and elastic constants for Co3V in the L12 structure.

Referances a(Å) B dB/dP C11 C12 C44 G B/G

Co3V This Work 3.537 210.9 2.92 302.73 169.21 175.49 132.01 1.621

VASP [2] 3.598 255.447 392.739 186.802 190.327 148.744 1.717

LMTO [3] 3.51 300

VASP [1] 3.514

Exp.[9] 3.55

Figure 2 Total and partial density of states for L12 Co3V. The Fermi energy is taken as energy zero.

CONCLUSION

In this paper, structural, electronic, elastic, thermodynamic and phonon properties of Co3V compound in the L12 phase has been studied by DFT. The structural properties including lattice constant, bulk modulus and first-order pressure derivative of the bulk modulus have been calculated and compared available data. I have also studied the mechanical properties of Co3V. The elastic constants have been calculated using the approach, the energy-strain method. The calculated elastic constants satisfy the mechanical stability criterion and the brittle of Co3V in the L12 phase is predicted by Pugh’s

criterion. The obtained values of B/G ratio for Co3V are in reasonable agreement with those obtained previously. The electronic structure calculation showed that Co3V exhibits metallic character. The electronic results indicate that the predominant contributions of the density of states at the Fermi level come from the Co 3d state for this compound. Phonon dispersion curves and their corresponding total and projected densities of states for the Co3V alloys in the L12 phase have been calculated for the first time in the framework of the density-functional perturbation theory. Temperature dependence of the constant-volume specific heat is determined from the obtained phonon spectra using the quasi-harmonic approach.

ACKNOWLEDGEMENTS

This work was supported by the Ahi Evran University Scientific Research Projects Coordination Unit. Project Number: EGT.E2.16.002.

Figure 3 Calculated phonon dispersion curves and density of states (DOS) for the Co3V in the L12 phase.

Figure 4 Calculated specific heat capacities at constant volume versus temperature for the Co3V

REFERENCES

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9. Saito S., Acta Cryst.12 (1959) 500-502. 10. Nagel L. J., Fultz B. & Robertson J. L., Philosophical Magazine

Part B, 75 (1997) 681-699. 11. Lin W.,. Xu J-H, and Freeman A. J., Mat. Res. Soc. Symp. Proc.

213 (1990) 131-136. 12. Baroni S., Dal Corso A., De Gironcoli S., Giannozzi P.,

Cavazzoni C., Ballabio G., Scandolo S., Chiarotti G., Focher P., Pasquarello A., Laasonen K., Trave A., Car R., Marzari N., Kokalj A., http://www.quantum-espresso.org.

13. Perdew P., Burke K., Ernzerhof M., Phys. Rev. Lett. 77 (1996) 3865.

14. Vanderbilt D., Phys. Rev. B 41 (1990) 7892. 15. Methfessel M., Paxton A., Phys. Rev. B 40 (1989) 3616. 16. Isaev E.I., QHA Project. http://qe-forge.org/qha 17. Wang S.Q., Ye H.Q., Phys. Stat. Sol. (b) 240 (2003) 45. 18. Uğur S., Arikan N., Soyalp F., Uğur G., Comput. Mater. Sci 48

(2010) 866. 19. Murnaghan F.D., Proc. Natl. Acad. Sci. USA 50 (1944) 697. 20. Born M., Huang K., Dynamical Theory of Crystal Lattices,

Clarendon, Oxford,1954. 21. Arıkan N., Iyigor A., Candan A., Uğur Ş., Charifi Z., Baaziz H.,

Uğur G., Computational Materials Science 79 (2013) 703–709. 22. Pugh S.F., Philos. Mag. 45 (1954) 823. 23. Arıkan N., Journal of Physics and Chemistry of Solids 74 (2013)

794–798. 24. Arıkan N., yigör A. İ, Candan A., Özduran M., Karakoç A., .

Uğur G., Uğur Ş., Bouhemadou A., Bin-Omran S., and Guechi N., Metals and Materials International 20 (2014) 765-773.

25. Petit T., Dulong P.L., Ann. Chim. Phys. 10 (1819) 395.


Variation of Trihalomethanes Content in the Drinking Water in the

City of Kumanova: Summer Season

Bujar H. DURMISHI*, Arianit A. REKA, Murtezan ISMAILI, Agim SHABANI, Arbana DURMISHI

Department of Chemistry, Faculty of Natural-Mathematical Sciences, State University of Tetova, Str. Ilindeni, n.n., 1200 Tetova, Republic of Macedonia


Abstract: The city of Kumanova and some villages of Likova municipality supplied with drinking water from surface water of Likova accumulation, which was previously treated at the plant. In the treatment of drinking water disinfection is the final stage, which is made with chlorine or chlorine preparations. During this process, natural organic matter (MON) react with chlorine and created trihalomethanes (THMs), which if are in high concentrations can be possibly carcinogenic to human health. The main purpose of this paper was to determine the THMs content variation in drinking water of the city of Kumanova in the summer season and comparing their presence with the Regulation of the Republic of Macedonia (as per the recommendations of EU and WHO). UV-VIS spectrophotometry was used as a method in order to determine the presence of THMs – a method based on Fujiwara’s reaction.

THMs were determined in five various sample points during the months of June, July and August of 2011. Results have shown that the content of THMs in the drinking water of Kumanova is below the recommended values of EU, WHO and the Government regulation. Seasonal variation average of THMs concentration was 41.29 13.36 µg/L. These results were higher compared with the spring of 2011 (33.29 9.21 µg/L). Except the main intended aim we had the protection of the population health as it is known that the high content of THMs in drinking water is very harmful and carcinogenic to humans.

Keywords:drinking water, health, trihalomethanes, UV-VIS spectrophotometry

INTRODUCTION

Water is the main factor for the existence of life

in our planet. Water is used for various purposes, such as drinking, cooking, maintaining proper hygiene etc., thus controlling the water quality is necessary in order to gather information about the level of contamination. Drinking water should be of high quality, it should meet the standards for daily usage and should not bear the potential of health risk. Water with such qualities is often limited, thus water is used from lakes, under-ground waters as well as artificially accumulated waters that initially must undergo treatment (cleaning and disinfection).

The treatment process of drinking water used in

households consists of: accumulation of water in water reservoirs, water aeration, coagulation, flocculation and precipitation, filtration and disinfection 1. During usage, water in households and industry is contaminated with inorganic, organic and other contaminants, and as such it returns to our environment. Furthermore, water is also contaminated by the usage of agricultural products.

Today, water that is considered drinkable should be subject to physical and chemical analysis; this also includes water from natural sources, such as wells. Treatment is done with physical and chemical methods such as: filtration, disinfection with chemicals and ultraviolet radiation. These methods have significantly increased the amount of accessible drinkable water for human consumption and at the same time have managed to reduce potential diseases.

In order to eliminate bacteria, viruses and micro-

organisms that can cause various diseases amongst humans and animals, drinking water is treated with chlorine or similar disinfectants 2.However, during the disinfection process, the organic matter present in water reacts with chlorine and bromine which results in byproducts. These byproducts are hazardous and impose hazardous cancerogenic concerns for the human health. These byproducts are divided in two main groups: haloacetic acids (HAA) and trihalomethanes (THM). In 1974 it was discovered that THMs are the main byproducts that are formed in the disinfected drinking water. These are a group of compounds that are formed


when chlorine reacts with broken down organic matter and vegetation. The main THM-s formed in such way are chloroform (CHCl3), bromdikloromethane (CHBrCl2), dibromochloromethane (CHBr2Cl) and bromoform (CHBr3)

3, 4. It is scientifically proven that THMs are

carcinogenic to animals and humans. Studies have shown that acute toxic doses of chloroform can cause depression of the central nervous system and cardiac effects. A study conducted by the California Department of Health found that women exposed to high levels of chlorinated byproducts have a 17.5% risk of miscarriage, while women who had less exposure to THMs have a lower risk, 9.5%. Because of the negative health impact, the US Environmental Protection Agency (US EPA) recommends that concentrations of THMs shall not exceed a value of 100 µg / L in tap water to customers5.

Of particular importance is the study of the

impact of various factors on the formation of THMs. Some of those factors are: pH, temperature, contact time, concentration of chlorides, natural organic matter, residual chlorine, bromide concentration etc 6, 7, 8. Each factor has a special effect on the formation of THMs. For example, increasing the pH and the contact time greatly increases the formation of THMs; increasing the temperature the reaction becomes much faster as well as the consumption of chlorine, which increases the formation of THMs 9.

As total trihalomethanes (TTHMs) formed are in

proportion to the amount of organic matter in the drinking water source, total THMs changes (their concentration) indicate changes in the quality of drinking water. The measurement of THMs in the right time is a valuable tool in monitoring the quality of drinking water, which also enables adjustments and improvements in the treatment process.

THMs are analyzed in laboratories by using

various gas-chromatographic methods. The most widely used method to determine the THMs is the EPA 502, a method with which THMs are analyzed by sweep and trap/detection-electrolytic conductivity. Chromatogra-phic methods such as GC-MS PT, HS-GC-MS and GC-PT are very expensive and require longer time for analysis and processing of results. Therefore, as a method for quantifying the THMs is used the UV-VIS spectrophotometry, which requires inexpensive instru-ments and reagents, and shorter term analysis and processing of results.


Drinking Water in the City of Kumanova

The city of Kumanova and some villages of the Likova municipality are supplied with water from the Likova dam, which is the oldest dam in the entire territory of the Republic of Macedonia. Likova dam was built in 1958 and its located 2 miles west of the same village, at an altitude of 478 m (Fig. 1). River Likova is rich in water and its basin is 110 km2, while the altitude ranges from 450 to 1350 m, with an average altitude of 1070 m. River Likova’s greater flow is during the spring

season, whereas the flow levels drop during summer and autumn when the region needs irrigation of arable land and potable water supply in the Kumanova region.

Figure 1. Likova dam - system I

Table 1.Some data in regards to the Likova accumulations

Volume of accumulation 1 500 000 m3 Used volume 1 300 000 m3 Length of accumulation 1 480 m Width of accumulation 120 m

Due to the high demand for quality water, 14

years later a second dam was built about 5 km west of Lake Likova, Gllazhnja locality (Fig. 2). The length of the dam is 344 m concrete wall with a width of 4 m and a height of 84 m. The Gllazhnja reservoir supplies water to 13 settlements and a part to the city of Kumanova.

Table 2. Some data in regards to the Gllazhnja accumulation.

Volume of accumulation 24 075 870 m3 Usage volume 22 160 000 m3 Length of accumulation 3162 m Width of accumulation 320 m Surface 96.5 ha


Fig. 2. Likova dam - system II (Gllazhnja area)

Working Methodology

The methodology involves collecting samples, their preparation and measuring, instruments and procedures of measured parameters. Experimental measurements were performed at the laboratories of the State University of Tetova.

Water Sampling

The sampling method has a great impact on the

results of the analysis obtained. Thus sampling is defined by international recommendations. Water samples are placed in clean glass containers, which are initially rinsed 2-3 times with the water that is about to be tested. The container is closed with glass lid. In order not to confuse the samples, all the containers are labeled with date, the type of water, sample site, time and the name of the person collecting the sample. Prior to collecting the sample the water needs to flow for about 10 min.

The time from collecting the sample and analy-

zing it should be as short as possible. Samples with high pollution should be analyzed within 12 hours, the ones with lower pollution within 24 hours, while non-polluted waters within 72 hours. During this time, the samples should be stored in a dark place and at a tem-perature of 3-4 °C to avoid possible changes as a result of the activity of microorganisms present in water.

Sample Points, Instruments and Reagents

Samples were collected from five sampling points of the city of Kumanova: K1 (Sinan Tatar Pasha Mosque), K2 (Fontana city center), K3 (Str. Dr. Ribar), K4 (Cafeteria Elib) and K5 (Str. Boris Kidriç). Drinking water samples from five sampling points are analyzed each week in the months June, July and August 2011 for the determination of THMs while using UV-Vis spectrophotometer (Ultrospec). The following reagents

were used: pentane, pyridine, 50% solution of NaOH, chloroform, bromoform and methanol. Determination of THMs

The determination of the concentration of THMs

in drinking water was performed with the method of UV-VIS spectrophotometry, a method that is highly sensitive and precise. With this method you can determine the total THMs in drinking water at 10 to 600 ppb (µg/L) as chloroform. This method relies mainly on the basis of chemical reaction Fujivar-s, where THMs with the respective reagent transform to a pink colored compound that absorbs in accordance with the Beer law made at wavelength 525 nm.

The determination of THM-s is made with UV-

VIS spectrophotometric method as described in scientific literature 10. With this method, ten mL of pentane were added in a normal dish containing1L of drinking water to be analyzed. The dishwas shaken for about 3 minutes and then was leftstill until the two separate layers were visible. Thepentane layer was then removed and was added to atest tube containing 2 mL of NaOH 50% and 3 mL ofpyridine. The test tube was placed in a water bath at 45°C for 30 minutes in order to relieve theevaporation of pentane. Afterwards, the bathtemperature was increased twice, at 55°C for 45minutes and at 95°C for another 45 minutes. After this, 2 mL of the pyridine layer (with a pink color) were removed and after the refrigeration was transferred to a 1 cmglass civet and the absorbance in 525 nm wasmeasured (Fig. 3).

For the preparation of the calibration curve, 1

mL bromoform and 1 mL chloroform all together were added to 1000 mL of methanol. Total concentration of THMs in this solution was 4.37 mg/mL, and this was the initial standard solution of THMs. Standard solution with concentrations 25, 50, 70, 100 and 125 g were prepared for the calibration curve by diluting the initial solution 4.37 mL/mL of THMs, where each solution is diluted with distilled water to the volume of 1 L (Fig. 4). These solutions were processed the same way as the drinking water samples.


Fig. 3. UV/VIS Absorption spectrum of THMs, = 50 g/L

(THM)/g/L

0 20 40 60 80 100 120 140

A

0.00

0.02

0.04

0.06

0.08

Fig. 4. Calibration curve for determination of THMs, July 2011


Results of this study are presented in Table 4 and

Fig. 5. These values are compared with state regulations of Macedonia, the WHO and the EU (Table 3).

The variation of THMs has changed during the above months within range 22.63 – 63.71 g/L. The lowest value was in June at sample point K5, while the highest values are at sample point K3 (August). The average values in June, July and August were: 26.91, 39.63 and 57.33 g/L respectively. The lowest average sample point was K1 with 37.55 g/L, while the highest observed average sample point was K3 with 46.20 g/L at. The seasonal average value with standard deviation was observed 41.29 13.36 g/L, which is below the allowed values of the state regulations. Compared to the parallel research of the drinking water in the city of Tetova, it can be concluded that during the summer season the city of Kumanova has higher content of THMs 11, 12. This is due to the fact that the water in the

Kumanova region has a higher content of organic matter because drinking water of Kumanoiva is supplied from surface water of the accumulation. Table 3. Standards/Recommendations for THM-s (mg/L) in world jurisdictions

Compo-und

WHO (1993)

USEPA

(2001)

Health Canada (2001)

Aus-ZR

(2000)

UK (2000)

UE (2001)

CHCl3 0.200 0.000* – – – – CHBrCl2 0.060 0.060* – – – – CHBr2Cl 0.100 0.000* – – – – CHBr3 0.100 0.000* – – – – TTHMs (THM/

OBSH) ≤ 1**

0.080 0.100 0.250 0.100 0.100

* The max target level of water pollution **The sum of THM levels shall not exceed 1 Table 4. Experimental results of THM-s (µg/L) and statistics

Sample point June July August

K1

K2

K3

K4

K5

Min

Max

Median

Average

Stan. Dev.

25.12

26.85

31.27

28.68

22.63

22.63

31.27

26.85

26.91

3.30

36.20

37.54

43.62

42.33

38.44

36.20

43.62

38.44

39.63

3.19

51.32

55.64

63.71

58.65

57.33

51.32

63.71

57.33

57.33

4.51

Figure 5. Summer variation of THMs in g/L

0

10

20

30

40

50

60

70

K1 K2 K3 K4 K5

June July August


CONCLUSION

Based on the above mentioned results it can be

concluded that: The summer variation of THMs content was below

the recommended value of the state regulation during the time this research was conducted and it does not impose a health risk to the population of this region.

The THM values are higher in the summer season, their monitoring is an imperative in order to ensure that the water is safe for use. Thus actions for reducing THMs are required, but should not negatively affect the water disinfection process.

It’s necessary that the relevant authorities take

appropriate actions to prevent and keep the THMs concentrations within limits, especially in the hot months when their values are much higher, as long term consumption can cause health problems.

We recommend that continuous monitoring of THMs is established in order to have a better picture of their impact on the health of the citizens in the region.

ACKNOWLEDGEMENTS

It is a pleasure as well as obligation to thank

Prof. Dr. Daut Vezi andProf. Dr. Hysen Reci, whose suggestions, directions and fruitful discussions contribu-ted considerably upon the experimental part of this work. We express gratitude to Mr. Bujamin Durmishi and Mr. Sc. Nagip Zendeli for their financial contribu-tions for reagents for determination of THMs. In parti-cular we would like to thank Mr. Sc. Arianit A. Reka for his support provided during the translation and the proofreading of this article into the English language.

REFERENCES

1Dr. sc. Bardha Korça (2002), “Analiza kimike e ujit”, WUS Austria,

Prishtinë, 95. 2Camel, V. & Bermond, A. (1998), The use of ozone and associated oxidation processes in drinking-water treatment. Water Research, 32, 3208-3222. 3Cragle, D.L., Shy, C.M.,Struba, R.J., Siff, E.J., (1985), A casecontrol study of colon cancer and water chlorinated in North Carolina. Water Chlorination: Chemistry, Environmental Impact and Health Effects. Chelsea. MI: Lewis Publishers Inc., Vol. 5, pp. 53. 4Nikolaou A., Lekkas T., Golfinopoulos S. and Kostopoulou M. (2002a), Application of different analytical methods for determination of volatile chlorination by-products in drinking water, Talanta, 56, 717-726. 5Elshorbagy, W., (2000), “Kinetics of THM Species in Finished

Water”, J. Water Resour. Plng. and Mgmt., ASCE, 126 (1), 21-28. 6Singer P.C. (1994), Control of disinfection by-products in drinking water, J. Env. Engineer., 120, 727. 7Singer, P.C. (1999), Humic substances as precursors for potentially harmfull disinfection by-products. Water Science and Technology, 40(9), 25-30. 8Zazouli, M.A., Nasseri, S., Mahvi, A.H., Mesdaghinia, A.R., Younecian, M., Gholami, M., (2007a), Determination of Hydrophobic and Hydrophilic Fractions of Natural Organic Matter in Raw Water of Jalalieh and Tehranspars Water Treatment Plants (Tehran). J.Applied .Sci., 7 (18): 2651-2655. 9Golfinopoulos S.K., Xilourgidis N.K., Kostopoulou M.N. and Lekkas T.D. (1998), Use of a multiple regression for predicting trihalomethane formation, Water Research, 32(9), 2821-2829. 10Huang J, Smith R, Gary C (1984), Spectrophotometric Determination of Total Trihalomethanes in Finished Waters. Journal AWWA, Vol. 76 Iss. 4, 168-171. 11Durmishi H. Bujar, D. Vezi, M. Ismaili, A. Shabani, Sh. Abduli (2012), Seasonal Variation of Trihalomethanes Concentration in Tetova's Drinking Water (Part B), World Journal of Applied Environmental Chemistry, Volume 1, Issue 2: 42-52. 12Bujar H. Durmishi (2013), The study of the trihalomethanes (THMs) content variation with advanced analytical methods in the drinking water in the city of Tetova; Ph.D. Disertation, University of Tirana, 77-78.


Use of Chitosan in the Polymer Composites as an Antibacterial Material

Hüsnügül YILMAZ ATAY

Department of Material Science and Engineering, İzmir Katip Çelebi University, 35620 Çiğli İzmir Turkey

[email protected]

Keywords: Chitosan; Polymer composites; Antibacterial coatings

INTRODUCTION

Chitosan is one of those antibacterial materials

as an active biomolecule that have a significant role everywhere in our life. It is a widely used natural, abundant biopolymer, and produced commercially from crab and shrimp waste shells. Those kinds of materials can be called environment purification functional materials which can effectively control the growth, reproduction of hazardous bacteria and also control toxic pollutants [1].

Chitin is generally represented as a linear

polysaccharide composed of (1 → 4) linked units of N-acetyl-2-amino-2-deoxy-d-glucose (Figure 1). Chitosan is a linear polysaccharide obtained by extensive deacetylation of chitin.

Figure 1. Structure of chitosan Nonetheless, inasmuch as it is virtually impossible to completely deacetylate chitin, what is usually known as chitosan is a family of chitins with different but always low degrees of acetylation. The capacity of chitosan to dissolve in dilute aqueous solutions is the commonly accepted criterion to differentiate it from chitin [2,3,4]. Synthesising of chitin and chitosan from marine crustacean shells is demonstrated in Figure 2.

Figure 2. Synthesising of chition and chitosan from marine crustacean shells

Chitosan is a very useful polymer for

biomedical applications in terms of its biocompatibility, biodegradability and low toxicity [2]. Owing to the positive charge on the C2 of the glucosamine monomer below pH 6, chitosan is more soluble and has a better antimicrobial activity than chitin [5]. Its positively charged amino group interacts with negatively charged microbial cell membranes, leading to the leakage of proteinaceous and other intracellular constituents of the microorganisms [6]. Chitosan acted mainly on the outer surface of bacteria. At a lower concentration (0.2 mg/mL), the polycationic chitosan does probably bind to the negatively charged bacterial surface to cause agglutination, whilst at higher concentrations, the larger number of positive charges may have imparted a net positive charge to the bacterial surfaces to keep them in suspension [5].

The antimicrobial action is influenced by

different factors such as the type of chitosan, the degree of chitosan polymerization, the host, the natural nutrient constituency, the chemical or nutrient composition of the substrates or both, and the environmental conditions. The development of complementary methods to inhibit the growth of pathogenic bacteria such as coating material-associated antimicrobial agents is an active area of research. Among their polymers, chitosan has received a significant attention as antimicrobial film-


forming agent due to its biodegradability, biocompatibility, cytotoxicity, and antimicrobial activity [5].

In this study, chitosan was used as an antibacterial material as powder and colloid to produce antibacterial coatings. An epoxy resin was converted to an antibacterial coating material. Chitosan was used in different ways; powder and colloid. For obtaining the powders, chitosan (Poly-(D) glucosamine, Sigma) was ground in a grinding mill at 25 ºC for 5 hours in the air. The aim of the comminution is to obtain homogeneous distribution and to increase the effect of the particles by increasing contact points. Chitosan colloids were prepared by dissolving in the acid solution. After a complete mixture by using magnetic stirrer at 25 oC for 20 minutes, homogeneous chitosan colloids were obtained.

Acrylic composites were prepared by adding chitosan powders and colloids to the polymeric matrix acrylic resin with different loading levels to assess the concentration dependence of material’s antimicrobial

affect. Glass substrates were coated with those polymeric composites. After the obtained composite coatings were subsequently dried for 24 hours at the room temperature in the air, no more curing process was performed. The sample codes and descriptions coatings are depicts in Table 1.

Table 1. Codes and descriptions of composite coatings

Sample codes

Chitosan Chitosan percentage in the composites (%)

CH00 None 0 CHP1 Ground Powder 1 CHP2 Ground Powder 5 CHC1 Colloid 0.01 CHC2 Colloid 0.05 CHC3 Colloid 0.10

Obtained samples were characterized by FTIR

and SEM. Antibacterial activity against Staphylococcus aureus (S. Aureus) was studied by applying entitled in vitro test. Zones of inhibition were estimated on the nutrient agar plates, and percent decreasing tests were performed.


Figure 3 depicts SEM micrographs of pure chitosan which is not indicated any crystalline structure. It shows the smooth areas which could be visualized of naturally polymeric material of chitosan. It can be seen that chitosan particles look like sphere, not flake, and they were well blended with dye homogeneously.

Figure 5. SEM micrographs of chitosan

SEM images of some of the composite coatings were given in Figure 6. Smooth and rough areas could be seen in chitosan incorporated into the coatings. As characteristic property of chitosan, large crystals were appeared. Rough surfaces and crystalline structures were raised as dominant features by increasing chitosan content. Concurrently, by increasing chitosan, the dissociation process occurred. In fact, the morphology of the coating samples was agreed well with this [7]. Increasing with colloid amounts, formation of flocculation and cracks appeared.

CH00 CHP2

CHC1 CHC3

Figure 6. SEM micrographs of chitosan

Figure 7 demonstrates antibacterial tests results of the coatings. As it can be seen in the Figure that there is no any antibacterial activity in the control sample of CH00. However, the inhibition zones around those specimens can be clearly seen in chitosan colloid reinforced coatings. Regarding the samples including chitosan powder, antimicrobial effects are seen on the surface of the coated region. It means the antimicrobial property works with direct contact of chitosan powders on the surface. To obtain the better results, particle size can be decreased to Nano scale if possible, as by this way the antibacterial effect of the particles can be increased due to increasing of contact surfaces. However, some


researchers observed that nanoparticles can have less inhibition effect on S. aureus ATCC 29737 than in free soluble form polymers. The reason is that nanoparticles have less positive charge for binding to the negative bacterial cell wall [8]. On the contrary, in another research, it was recorded that due to the special character of the nanoparticles, the chitosan nanoparticles can present higher antibacterial activity against S. aureus [9]. Similarly, larger surface area of the nanoparticle and affinity with bacteria cells, which yields a quantum-size effect, has influence in the antibacterial action [10].

CH00 CHP2

CHC1 CHC3

Figure 7. Zone of inhibition of cotaings

Chitosan reinforced composite samples were subjected to percent decreasing test also. In this test a plate counter agar solid culture medium was poured into the plates that were subsequently incubated at 37 °C for 24 hours so that the Vital cells, eventually presented, could grow into colonies. The microorganisms’ colonial

presence was then evaluated, by counting the colony-forming units per Petri plate (CFU/mL). Used bacteria were S. Aureus (ATTC 11228). The difference between the number of the bacteria obtained at zeroth hour and the one obtained after 24 hours will show the antibacterial performance (Equation 1).

100% xA

BAdecrease

….. (Eq.1.)

The initial number of bacteria was 2000, and they were counted again after 24 hours. The results are shown in Table 2 below. It can be expressed that chitosan reinforced coatings showed antibacterial property. The

results support inhibition test results. As mentioned above, colloid chitosan demonstrated the antimicrobial activity much better in the composite comparing with powder chitosan reinforced composites.

Table 2. Decreasing test results of the coated samples

Code

Bacteria quantity after 24 hours

CH00

1650

CHP1 1345 CHP2 1056 CHC1 0 CHC2 0 CHC3 0

In addition, the prohibition activity of chitosan depends on different types of factors, such as solid surface characteristic and the morphology. Particle size, membrane and fiber thickness cause to occur different results. It was investigated the effect of particle size and shape of chitosan powder on S. aureus, and it was recorded that antibacterial activity was improved by decreasing the particle size. Conversely, the antibacterial property chitosan powders depend on shape as well as specific surface area. The researchers showed that chitosan powders in the range of 74–500 μm looked like a flake or board, but they looked like

spheres in the range of 37–63 μm [11,12].

Soluble chitosan and its derivatives are more efficient for preventing bacterial growth because soluble chitosan allows reaction with the counterparts to a sufficient degree by existing as a disassociating form in solution and an extending confirmation [12]. Solid chitosan only gets into touch with solution through surface, such as fibers, membrane, hydrogels, microspheres and nanoparticles. However, by extending conformation contact to solution, hydrogels can be formed by covalently cross-linking chitosan with itself. Chitosan particulate systems can form dispersion in solution with the considerable reactive surface area [10].

CONCLUSION

The antibacterial behaviour and effectiveness of solid and colloid chitosan in a polymer matrix were investigated. The chitosan particles look like spheres, not flake and this leads to a smooth surface at the composite coating. The composites were mixed with chitosan compatibly. It was investigated that chitosan can be considered as an effective antibacterial additive. Increasing loading level of the chitosan colloids in the polymer composites increased inhibition zone. Colloid chitosan demonstrated much better antimicrobial


activity in the composites comparing with powder chitosan reinforced composites.

Against other antibacterial materials, chitosan is a nontoxic, harmless and environmentally friendly vegetable material. Using this material at the points of our life will be more healthful for people.

ACKNOWLEDGEMENTS

The authors would like to acknowledge to Ege University, Dokuz Eylul University and Muğla Sıtkı

Koçman University.

REFERENCES 1S.-G. Hu, C.-H. Jou and M.-C. Yang, “Biocompatibility and

antibacterial activity of chitosan and collagen immobilized poly (3-hydroxybutyric acid-co-3-hydroxyvaleric acid)”, Carbohydrate Polymers, 58 2004 173-179. 2C. Peniche, W. Argüelles-Monal and F.M. Goycoolea. Monomers, Polymers and Composites from Renewable Resources. Chitin and Chitosan: Major Sources, Properties and Applications. Elsevier March 2008 Chapter 25, 517-542. 3E.I. Rabea, M.E.-T. Badawy, C.V. Stevens, G. Smagghe and W. Steurbaut, “Chitosan as antimicrobial agent: applications and mode of

action”, Biomacromolecules, 4 2003 1457–1465.

4V.K. Mourya, Nazma N. Inamdar. Chitosan-modifications and applications: Opportunities galore. Reactive & Functional Polymers. 68 2008 1013-1051 5P.K. Dutta, S. Tripathi, G.K. Mehrotra and Joydeep Dutta. Perspectives for chitosan based antimicrobial films in food applications. Food Chemistry. 114 2009 1173-1182. 6F. Shahidi, J.K.V. Arachchi and Y.J. Jeon. Food application of chitin and chitosans. Trends in Food Science and Technology. 10 1999 37–51. 7M. Abdelrazek, I.S. Elashmawi and S. Labeeb. Chitosan filler effects on the experimental characterization, spectroscopic investigation and thermal studies of PVA/PVP blend films. Physica B: Condensed Matter. 405 2010 2021-2027. 8A.M.M. Sadeghi, F.A. Dorkoosh, M.R. Avadi, P. Saadat, M. Rafiee-Tehrani and H.E. Junginger. Preparation, characterization and antibacterial activities of chitosan, N-trimethyl chitosan (TMC) and N-diethylmethyl chitosan (DEMC) nanoparticles loaded with insulin using both the ionotropic gelation and polyelectrolyte complexation methods. International Journal of Pharmaceutics. 355 2008 299–306. 9L.F. Qi, Z.R. Xu, X. Jiang, C.H. Hu and X.F. Zou. Preparation and antibacterial activity of chitosan nanoparticles. Carbohydrate Research. 339 2004 2693–2700. 10M. Kong, X.G. Chen, K. Xing and H. J. Park. Antimicrobial properties of chitosan and mode of action: A state of the art review. International Journal of Food Microbiology. 144 2010 51–63. 11T. Takahashia, M. Imaia, I. Suzukia and J. Sawai. Growth inhibitory effect on bacteria of chitosan membranes regulated by the deacetylation degree. Biochemical Engineering Journal. 40 2008 485–

491. 12T. Phaechamud. Hydrophobically modified chitosans and their pharmaceutical applications. Journal of Pharmaceutical Science and Technology. 1 2008 2–9.


Density Functional Study of the Structural and Electronic Properties

of Ir2ScBi

Nihat ARIKAN

Ahi Evran Üniversitesi, Eğitim Fakültesi, İlköğretim Bölümü

*[email protected]

Keywords:Heusler compounds, DFT, electronic structure, elastic

INTRODUCTION

Heusler alloys have been of interest since their discovery in 1903 by Friedrich Heusler. It has been reported that it was possible to make ferromagnetic alloys from non-ferromagnetic constituents [1]. Heusler alloys are ternary X2YZ compounds crystallizing in the L21structure. The cystal lattice belongs to the spacegroup Fm3m.X and Y are usually transition metals, while Z is a main group element. X (the more electronegative element) occupies the Wykhoff position 8c(1/4,1/4,1/4), Y is on 4b(1/2, 1/2,1/2), and Z is on 4a (0, 0, 0).They are considered to be promising thermoelectric materials because of their potential role in the realization of environmentally friendly technology. Many fullHeusler alloys have been prepared and reported by experimentalists and also by theoreticians.Ir-based alloys have attracted extensive interest for potential high temperature structural applications [2-4].For Ir2ScBialloy, Gillessen [5] has theoretically reported the formation energy, lattice constants and magnetic moment. In an effort to understand them in the present work,first principle calculations are performed to investigate the fundamentalproperties of Ir2ScBi alloy withL21 structure including total energy, lattice constant, electronicband structure, density of states, mechanical properties, and ductility as well. This paper is organized as follows. Section 2is devoted to thedescription of our methods of calculation. I discuss the results of my calculations in Section 3for the structural and mechanical properties of Ir2ScBi alloy, includingcomparison with theory. The electronic structure of this alloy is examined. A summary is given in Section 4.

METHOD

For our calculations, we use the generalized gradient approximation (GGA) in the scheme of Perdew–Burke–

Ernzerhof (PBE) [6] with a plane wave pseudopotential

approach, using the implementations in the Quantum-ESPRESSO package [7]. The wave functions were expanded into plane waves with kinetic energies of up to 40 Ryd. Self-consistent solutions of Khon–Sham equations were obtained by employing a set of 60 k-points within the irreducible part of the Brillouin zone. The elastic constants were obtained by calculating the total energy as a function of volume-conserving strains that break the cubic symmetry. Bulk modulus B, C44, and shear modulus C' = (C11-C12)/2 were calculated from hydrostatic pressure e = (, , , 0, 0, 0), tri-axial shear strain e = (0, 0, 0, , , ) and volume-conserving orthorhombic strain e = (, , (1+)-2-1, 0, 0, 0), respectively [8]. Hence, B was obtained from the following equation:

∆𝐸

𝑉=9

2𝐵𝛿2

whereV is the volume of unstrained lattice cell, and Eis the energy variation as a result of an applied strain with vector e = (e1,e2, -e3, e4,e5,e6). C′can be calculated from

Δ𝐸

𝑉= 6C′δ2 + 0δ3

The two expressions above yield 𝐶11 = 3𝐵 + 4𝐶 ′ /3

and 𝐶12 = 3𝐵 − 2𝐶 ′ /3, and C44 is given by

Δ𝐸

𝑉=3

2𝐶44𝛿

2

The details on the calculation of elastic constants have been describedin our previous papers [9].


The considered Heusler Ir2ScBi alloy has been examined in the L21 phase. In the L21 phase, Ir2ScBi are isostructural with Cu2MnAl and crystallize in a cubic structure with the space group Fm3 m (No 225 in the X-Ray Tables) as shown in the Figure 1. The primitive cell


of the L21structure contains four atoms that form the base of the fcc primitive cell. The equilibrium lattice constant was determined by minimizing the total energy with respect to different values of the lattice constant. Then, the total energy-volume data are fitted to the Murnaghan equation of state [10] to obtain the equilibrium lattice constant a0, bulk modulus B and first-order pressure derivative of the bulk modulus B'. The obtained values of a0, B and B' for the Ir2ScBi are tabulated in theTable 1 along with the existing theoretical data for the sake of comparison. The obtained value for lattice constant of Ir2ScBi is in good agreement with the available theoretical result [5].

Fig. 1 Crystal structure of the full-Heusler alloys X2YZ

Table 1 Calculated lattice constants (in Å), bulk modulus (in GPa) and pressure derivative of the bulk modulus and the total magnetic moment Mt (B) for Ir2ScBi in the Heusler phase. Referances a(Å) B dB/dP Mt

Ir2ScBi This Work 6.687 50.1 2.1 1.19

Theory [5] 6.676 0.54

The elastic properties of a cubic single-crystal are completely defined by three independent elastic constants, namely C11, C12 and C44. The C11 gives the resistance to the unidirectional compression (compression along the principal directions <100>), C44 presents the resistance to shear deformation across the (100) plane in the [110] direction, while C12 hasn’t a

simply physical meaning but its combination with C11 and C44 gives additional information about the elastic behaviour of materials. The herein obtained values of C11, C12 and C44 for the considered material are summarized in theTable 2. The calculated values of the elastic constants for Ir2ScBi satisfy the mechanical stability conditions for a cubic structure [11]: C11 –

C12<0, C11>0, C44>0, C11 + 2C12>0. There are no available experimental or theoretical data for the elastic constants for the Ir2ScBi alloy in the L21 phase, so these predicted values are still waiting experimental confirmation. In order to investigate the ductility and brittleness properties of Zr3Al andSc3Al, the ratio of bulk modulus to shear modulus, B/G, has been calculated. This ratio can be considered as an empirical criterion of the extent of the fracture range in the materials [12]. If the ratio of B/G is higher than 1.75,

then the material behaves in a ductile manner. If it is less than 1.75, then that material demonstrates brittleness. The B/G values are 2.779 for this material. The B/G values of Ir2ScBi indicate the ductile nature of the material. Spin-polarized band structures of Ir2ScBi alloy for spin-up (majority-spin) and spin-down (minority-spin) alignments are shown inthe Figure 2 along the high symmetry directions in the first Brillouin zone together with total densities of states. Both spin-up and spin-down band structures show that no energy band gap in this material indicating its metallic character. Total and atomic-resolved projected densities of states (DOSs) for the considered alloy as calculated for equilibrium geometries are presented in figure 3. DOSs diagrams show no energy gap at the Fermi level for the considered alloy. This confirms that the majority-spin (up) and minority-spin (down) exhibit metallic behaviour. The calculated values of the total magnetic moment (Mtot) for Ir2ScBi alloy is given intheTable 1 along with the existing theoretical result [5] for comparison. The calculated magnetic moment is bigger than the theoretical data. Table 2 Calculated the elastic constants (in GPa) for Ir2ScBi in the Heusler phase. Referances B C11 C12 C44 G B/G

Ir2ScBi This Work 38.91 25.62 43.45 19.1 14 2.779

.

Figure 2Calculated minority spin, majority spin-band structure, and total DOS for Ir2ScBi


Figure 3 the total and partial DOS of Ir2ScBi Heusler alloy

CONCLUSION

In this paper, the structural, electronic, magnetic, elastic properties of Ir2ScBi, using the ab initio pseudopotential method within the GGA of the DFT has been studied. The obtained value for the equilibrium lattice parameters is in good agreement with the existing theoretical data. Analysis of the computed single-crystal elastic constants shows that Ir2ScBi in the L21 phase is mechanically stable. Band structure and density of states

diagrams confirm the metallicity of the Ir2ScBi alloy in the L21 phase.

ACKNOWLEDGEMENTS

This work was supported by the Ahi Evran University Scientific Research Projects Coordination Unit. Project Number: EGT.E2.16.002

REFERENCES

[1] Heusler F. ‘‘Über magnetische Manganlegierungen’’ Verhandlungen der Deutschen Physikalischen Gesellschaft (in German) 5 (1903) 219.

[2] OdeM., MurakamiH., OnoderaH., Scripta Mater. 52 (2005) 1057. [3] HillP. J., CornishL. A., WitcombM. J., Journal of Alloys and

Compounds. 280 (1998) 240. [4] ArıkanN., CharifiZ., BaazizH., UğurŞ., ÜnverH., UğurG., Journal

of Physics and Chemistry of Solids 77 (2015) 126–132. [5] GillessenM.,Massgeschneidertes und Analytik-Ersatz: über die

quantenchemischenUntersuchungeneinigerterna¨rerintermetallischerVerbindungen. Ph. D. Dissertation, RWTH (2009) Aachen University.

[6] PerdewP., BurkeK., ErnzerhofM., Phys. Rev. Lett. 77 (1996) 3865.

[7]BaroniS.,dalCorsoA., DeGironcoliS.,GiannozziP.,CavazzoniC.,BallabioG., ScandoloS.,ChiarottiG.,FocherP.,PasquarelloA.,LaasonenK.,TraveA.,CarR., MarzariN.,KokaljA., http://www.quantum-espresso.org.

[8] WangS.Q., YeH.Q., Phys. Stat. Sol. (b) 240 (2003) 45. [9] UğurS., ArikanN., SoyalpF., UğurG., Comput. Mater. Sci 48

(2010) 866. [10] MurnaghanF. D., Proc. Natl. Acad. Sci. USA 50, 697 (1944). [11] WangJ., YipS., PhillpotS. R., and WolphD., Phys. Rev.Lett. 7,

4182 (1993). [12] PughS.F., Philos. Mag. 45 (1954) 823.


Hydrothermal Reaction of Trepel with Ca(OH)2

Arianit A. REKAa, Blagoj PAVLOVSKIb, Njomza BUXHAKUa, Bujar DURMISHIa, Ahmed JASHARIa, Shefket DEHARIa, Kiril LISICKOVb

aUniversity in Tetovo, Faculty of Natural Sciences and Mathematics, Department of Chemistry, str. Illinden n.n., 1200

Tetovo, Republic of Macedonia bSs. Cyril and Methodius University in Skopje, Faculty of Technology and Metallurgy, Intsitute of Inorganic

Technology, str. Ruger Boskovic 16, 1000 Skopje, Republic of Macedonia


Keywords:trepel, diatomite, compressive strength, ceramic, hydrothermal treatment

INTRODUCTION

Inorganic, non-metallic, raw materials are suitable for various applications. Silicon dioxide (also known as silica) is a widespread in nature and it occurs in various forms [1-4].

Trepel is form of silica (SiO2) derived either from thedecomposition or alterations of chert or as a residual product fromthe decomposition of a highly siliceous limestone.Diatomite or diatomaceous earth (also known as tripolite,kieselguhr, infusorial earth) is a hydrous or opalescent form of silica[5]. Trepelis a natural mixture of diatomite and clay minerals [6]. It’s a

typical sedimentary rock of biogenetic origin, with greyish-white color,weakly bound, soft (1-2 by Mohs) and very light, porousmaterial [7].

Trepel is a suitable raw material for production of ceramic products, for synthesis of zeolites, as absorbent for cleaning of raw industrial waters etc [8-12]. In this paper the aim is to use trepelas raw material for production of porous ceramicproducts.


In this paper, the following materials were used as starting materials:

- Trepel from the Brod-Gneotine (Bitola region, Republic of Macedonia), and

- Calcium hydroxide (product of SIGMA) Physical examinations of trepel The physical properties of the examined trepel are

shown in table 1, while a macroscopic picture of the raw material (trepel) is shown in figure 1. Table 1. Physical properties of trepel from Brod-Gneotino

Property Value

Bulk density 0.77 – 0.93 g/cm3 Water absorption 67 – 79 %

Open porosity 52-67% Total porosity 67 – 76 % Specific mass 2.45 g/cm3

Figure 1. Raw trepel from Brod-Gneotino

The chemical examination of trepel was performed

with the classical chemical silicate procedure. The results of this analysis are shown in table 2.


Table 2.Chemical analysis of trepel form Brod-Gneotino

Oxide Mass (%)

SiO2 55.86 Al2O3 15.29 Fe2O3 8.28 CaO 2.90 MgO 2.78 K2O 2.00

Na2O 2.33 SO3 0,.69 LOI 9.60 Total 99.77

XRPD examination of trepel X-ray powder diffraction (XRPD) analysis was

performed on the DRON X-ray diffractometer (Cu Kα

radiation, Wavelength λ=1,54056 mm, Testing interval - 70°, Registration voltage 38 kV, Current intensity 18 mA).With the XRD examination of trepel the following minerals are identified:quartz,feldspars,chlorites,illite-hydromica.

Trepel contains amorphous silica which causes the bulge in the background peak levels. Results of the XRPD examination are shown in Fig. 2.

Figure 2. XRPD spectra of trepel from Brod-Gneotino

Microscopic examinations of trepel The microscopic examinations (performed with the

polarizing translucent light) show that the sample is characterized with a micro-cryptocrystalline ground mass of optic isotropic nature. This groundmass of trepel is composed of opal inside of which there are very fine to super fine grained quartz, feldspars, chlorites, illite-hydromica.

The SEM examinations confirm the results of the polarizing microscopy. Alga Diatomeae are shown on the SEM-pictures (fig. 3) resembling disks of sunflower with or without peripheral ends. These “sunflower”

disks are completely perforated with discrete caverns, hollows along the total disk surface. It’s evident also

that the trepel porosity is connected with the abovementioned caverns inside the surface of the globular structures.

Figure 3. SEM of trepel (microfossil-diatomite)

Figure 4. SEM of trepel mass composed of microrelics – opal globules of biogenetic origin

Thermal examinations of trepel Differential-thermal and thermo-gravimetrical

(DT/TG) analyses of the trepel were performed with Stanton Redcroft, England – apparatus, under the following experimental conditions: Temperature range - 20 – 1000 °C; speed of heating 10 °C/min; sample mass 13.57 mg; gas environment – air; material carrier – ceramic pot. Results of the differential-thermal analysis and the thermo-gravimetrical analysis of the trepel are shown in fig. 5.


Figure 5. DTA/TGA examinations of trepel

Based on the DTA/TGA examinations showed on Fig. 5 the following can be concluded:

- The DTA curve shows a wide endothermic peak with a minimal value of 180 °C which is as result of separation of the rough water bonded to the clay minerals and opal component. At the same curveevident is the presence of two exothermic peaks with maximum values of 323 °C and 454 °C which are as result of burning of organic matter in trepel.

- Based on the TGA curve it can be concluded that during the heating process evident is the loss in mass. At the temperature interval 108 °C and 260 °C there is a mass loss as result of separation of bonded water from the opal component and the clay minerals. In the temperature interval 260 °C – 500 °C is the most intensive loss in mass as result of burning of the organic component. In the temperature interval over 500 °C the thermo-gravimetric curve continues to show loss in mass, though this loss is with much lower intensity. In this interval there is dehydration of the clay component and the opal component.

FTIR examinations of trepel Infra-red spectroscopic examinations of trepel are

shown in Fig 6.

Figure 6. IR spectra of trepel from Brod-Gneotino

IR spectroscopy is a widely used method when examining amorphous SiO2, and especially when studying the way the hydroxyl groups are bonded on the surface of the amorphous SiO2. The absorption bands at 1645, 1105 and 795 cm-1 are as result of the presence of the amorphous SiO2 in trepel. The main Si-O band for amorphous SiO2 is at 1036 cm-

1, which in this case is shifted towards the smaller values of the frequency which is as result of the substitution of the Si+4 ions in the tetrahedral position with trivalent cations. Absorption bands at 550 cm-1, 630 cm-1, 720 cm-1and 1003 cm-1 are as result of the presence of feldspar in trepel. The absorption band at 3442 cm-1 is as result of the presence of hydroxyl groups in trepel as well as result of the presence of absorbed H2O. The absorption band at 3622 cm-1 is another evidence of the presence of the absorbed H2O, while the band at 1650 cm-1 is due to the presence of hydroxyl groups.

Sample preparation A homogenous mixture of 80 % trepel and 20 %

calcium hydroxide was prepared. The probes were obtained with a cylindrical mold and were pressed on a mechanical press at 2 MPa and 10 MPa. Further on, the probes were hydrothermally treated at 130 °C for a period of 3 hours. Upon autoclaving the probes were first dried at constant mass, and then their physical-mechanical properties were determined.

Figure 7. Hydrothermally treated probes (3 hrs, 130°C)

Physical-mechanical properties of products The following physical-mechanical analyses were

performed on the ceramic products obtained from the hydrothermal synthesis (autoclaved in period of 3 hours at 130 °C): bulk mass, porosity and compressive strength.


Results of the physical-mechanical analyses of the

products obtained during the hydrothermal treatment (130 ºC for 3 hours)are shown in table 3. Table 3. Physical-mechanical properties of products

Property Value

Bulk density 0.85 g/cm3 Total porosity 61%

Compressive strength (prepared at 2 MPa)

5.14 MPa

Compressive strength (probes prepared at 10 MPa)

22.54 MPa

XRPD examinations of product

The results of the XRPD examination of the

product obtained upon the hydrothermal treatment at 130 °C for a period of 3 hours is shown in figure 8.

Figure 8. XRD of product(X= xonolite, T= tobermorite, 1= quartz, 2 = feldspar, 3= ilite, 4= mulite, 5= tridymite)

Based on the results obtained from the XRPD examination, it’s evident that during the hydrothermal treatmentnew phases are formed and are clearly seen on the XRPD diffractogram.

Infra red examinations of product The results of the infra red examinations of the

product obtained during the hydrothermal treatment at 130 °C for a period of 3 hours is shown in figure 9.

Figure 9. IR spectra of product

As showed in fig. 9, the main Si-O band at 1014 cm-1is due to substitution of the Si4+ ion in the

tetrahedral position with three valent ions. The absorbtion band on the region form 3400 to 3700 cm–1 is due to the presence of OH groups.The bands at 3450 cm-1 and 1630 cm-1are as result of the new phase

tobermorit present in the sample. The band at 640 cm-1 is due to the presence of monocalcium silicate hydrate CSH(I).

DTA/TGA examinations of product The results of the thermal examinations of the

product obtained during the hydrothermal treatment at 130 °C for a period of 3 hours is shown in figure 10.

Figure 10. DTA/TGA examinations of product The differental-thermal analysis and the thermo-gravimetric analysis of the product show the following results: - the wide endothermic peak at 130 °C is due to the dehidratation of the mass - the exothermic peak at 360 °C is due to the crystallization of the initial mass - the small endothermic peaks at 420 and 540 °C are due to the presence of C2SH (A) - hilldebrandit in the sample - the endothermic peak at 665 °C is due to the presence of tobermorite in the probe - the endothermic peak at 750 °C is due to the presence of C2SH (C)– dicalcium silicate hydrate phase - the exothermic peak at 860 °C is as result of the crystallization of CSH(B) into wollastonite.


CONCLUSION

Based on the results shown in the previous section it can be concluded that during the hydrothermal treatment of the samples prepared with 80% trepel and 20% calcium hydroxide, new phases are formed. These newly formed calcium silicate hydrates (mainly tobermorite, xonotlite and gyrolite) reflect in the

increased physical-mechanical characteristics of the obtained products. Products have total porosity of 61% and compressive strength over 5 MPa (5.14 MPa and 22.54 MPa).

ACKNOWLEDGEMENTS

I would like to express my gratitude to my mentor Prof. dr. BlagojPavlovski, who offered his continuous advise, encouragement, systematic guidance and selfless support during the whole process of preparing this paper.

REFERENCES 1Iler, R.; The Chemistry of Silica, 15–16, A Wiley-Interscience Publication, John Wiley & Sons, 1978. 2Callister, W. D. Jr.; David G. Rethwisch; MaterialScience and Engineering, John Wiley & Sons Inc., pp.464–465, 2010.

3Holleman, A. F., Wiberg, E.: Lehrbuch der AnorganischenChemie, Walter de Gruyter, Berlin, New York, p. 975,2007. 4Kingery,W. D.; Introduction to Ceramics, John Willey &Sons, Inc., New York, London, 1960. 5Cekova, B.; Pavlovski, B.; Spasev, D.; Reka, A.; Structural examinations of natural raw materials pumice and trepel from Repulic of Macedonia; Proceedings of the XV Balkan Mineral Processing Congress, Sozopol, Bulgaria, June 12 – 16, 2013, 73-75 6Reka, A., ; Durmishi, B.; Jashari, A.; Pavlovski, B.; Buxhaku, Nj.; Durmishi, A.; Physical-Chemical and Mineralogical-Petrographic Examinations of Trepel from Republic of Macedonia; International Journal of Innovative Studies in Sciences and Engineering Technology, Vol.2, Issue 1, 2016, 13–17. 7Pavlovski, B; Jančev, S.; Petreski, L.; Reka, A.; Bogoevski, S.; Boškovski, B; Trepel – a peculiar sedimentary rock of biogenetic origin from the Suvodol village, Bitola, R. Macedonia; Geologica Macedonica, Vol. 25, No. 1,2011, pp. 67–72. 8Pavlovski B.; Bunteska B.; Light ceramic materials obtained under hydrothermal conditions; XVI congress of Chemists and Technologists of Macedonia, Faculty of Technology and Metallurgy, Skopje (1999). 9Pavlovski B, Bunteska, Jashmakovski B., Silica construction materials, Faculty of Technology and Metallurgy (1990) 10Reka, A.; Pavlovski, B.; Influence of the nature of Silica on physical and mechanical properties of lightweight silicate bonded building products obtained by hydrothermal treatment, XVIIIth Congress of Chemists and Technologists of Macedonia, Ohrid, Republic of Macedonia, 2004. 11Reka, A.; Anovski, T.; Bogoevski, S.; Pavlovski, B.; Boškovski, B.; “Physical-chemical and mineralogical-petrographic examinations of diatomite from deposit near village of Rožden, Republic of Macedonia”, Geologica Macedonica, Vol. 28, No. 2, pp. 121–126 (2014).


Antioxidative Properties of a Special Traditional Food Plant Roots:

Urtica Urens

Emine BAĞDATLI,a* Aliye GEDIZ ERTURK,a Melek GÜL b

aDepartment of Chemistry,Faculty of Art and Science, Ordu University, TR-52200, Ordu, Turkey

bDepartment of Chemistry, Faculty of Art and Science, Amasya University, TR-05000, Amasya, Turkey

*[email protected]

Keywords:Urtica urens, Small nettle, Root, Antioxidantactivity

INTRODUCTION

Nettle herb plays an important role both in the

diet and medicinal applications. Urtica urens is a member of the family Urticaceae is commonly known as dwarf nettle, annual nettle or small nettle. This plant is known as a powerful diuretic,1 hemostatic, hypotensive2 and as astringent, hepatic, antirheumatic, antiinflammatory, analgesic agent and is used to promote fertility,3 as anti-aging4 and antinociceptive. Urtica extracts show antioxidant and inducible oxidant inhibitory activity in lipid peroxidation assays. Young leaves of nettles have a very nutritious food, rich in vitamins, minerals, flavonoids, antocyanins, carotenoids and amino acids.5,6

Figure 1.Urtica dioica (common nettle), Urtica urens (small nettle), Urtica pilulifera (Roman nettle), respectively.7

The whole part of Urtica urens can be used to

prepare homeopathic medication. The obtained solution from annual nettle is strained and can be diluted to desired levels. It can be used to treat hives and as a component of a homeopathic after-bite gel.8 In official and folk medicine, Urtica urens is used asdiuretic and for dermal, bronchopulmonary, gynecological, neurological, and antirheumatic applications. Aqueous and methanol extracts of the herb were active against Staphylococcus aureus, Streptococcus pyogenes, E. coli, and P. Aeruginosa. The extract of Urtica urens seeds

exhibits in vivo chemopreventive potential, useful antioxidant properties, and protects the liver from the hepatotoxic action of toxic substances such as aflatoxin B1.1 It is found to have high protein content (13.25 – 26.44%)., fiber and ash at 16.08 – 23.08% and 13.0 – 27.75%, respectively. It has also significant contents of phenolic substances and the elements of Ca, K, P, and Zn.2 The roots of Urtica urens are used in Europe for self-treatment of bening prostate hyperplasia.3

For this investigation, the nettle was collected

in July 2015, from Demirci area of Karagol plateau in Giresun, Turkey. Small-leaved nettle is grown spontaneously under the natural conditions. In the literature, any research is not available about Urtica urens grown in this region. There are few research about antioxidant property of Urtica urens genus grown in Turkey. The top part of the plant collected from South Africa and India were worked for antioxidant ability.9,10

The goal of the current investigation is the

evaluation of the in-vitro antioxidant activities of 70% aqueous-methanol, ethyl acetate, petroleum ether extracts of the roots of Urtica urens. The determination of antioxidant capacity of the extracts were done by comparing the solvent efficiency in extraction. and phytochemical screening of the extracts were also done through the determination of total phenolic and flavonoid content.



The roots of the plant has a special importance for the local pepole in the Blacksea region of Turkey. They widely use this part of the plant to treat urinary problems, diabetes, cough, prostate disease, some skin problems and nervous diseases. Many researchers have investigated mainly the aerial parts of the plant for theurapeutic use.11, 12Although, the roots of the plant have many applications as alternative medicine have been rarely studied. In this study, we aimed to investigate the antioxidative properties of this part ofthe nettle.

Firstly, extracts of the roots have been prepared in the solvents with different polarities: 70%methanol (root 1), ethyl acetate (root 2) and petroleum benzine (root 3) using the soxhlet apparatus. To investigate the antioxidative properties of the samples DPPH (2,2-Diphenyl-1-picrylhydrazyl) free radical scavenging,13total reducing power,14 the ferrous ion (Fe+2) chelating,15süperoxide anion (O2

•-) radical scavenging with NBT (nitro blue tetrazolium chloride)16and total antioxidant capacity determination with ferric thiocyanate17methods were applied. Additionally,some phytochemical analysis of the plant extracts: total phenolic and total flavanoidcompounds content definition assays18, 19were carried out.

The first applied assay is DPPH radical scavenging has shown the highest activity of root 1 compared with the standards: BHA (Butylated hydroxyanisole), BHT (Butylated hydroxytoluene), trolox and resorcinol. This assay assigned the hydrogen atom or electron releasing tendency of the samples to break the radical chain reaction or scavenge the free radicals.

Figure 2.DPPH Radical scavenging activity of the extracts.

Metal chelating activity of the root samples were carried out with ferrozine which is a ferrous ion capturing component. Ferrous ion is responsible of forming free radicals via Haber-Weiss and Fenton reactions in organism. Root 1 has the highest metal chelating activity among the samples according to a correlation with BHT, trolox and EDTA (Ethylenediaminetetraacetic acid) standards.

Figure 3.Metal chelating activity of the extracts.

Total reducing power assay is related to detection of the concentration for the reducing components of the samples. This molecules can supply reducing property by giving a hydrogen atom to the radical chain reaction and terminate the process. This assay indicated the highest reducing power of root 3.Theexperiment was performed againstEDTA, trolox and gallic acid antioxidant compounds.

Figure 4.Total reducing power of the extracts.

Superoxide anion radical scavenging of the

extracts was performed with NBT as the fourth test. In this assay superoxide anion (O2

•-)was genarated with NADH (Nicotinamide adenine dinucleotide)/PMS (Phenazine methosulfate)/O2 system. In the presence of superoxide anion scavenging compounds, NBT reduction is inhibited and low absorbance values are expected.Root 1 and 2 have the nearest superoxide radical scavenging activity according to the standards of BHT, BHA and trolox.


Figure 5.Superoxide radical scavenging activity of the extracts.

Total antioxidant capacity assay was performed by determining inhibition of linoleic acid peroxidation of the extracts. The resulting peroxides form the ferric thiocyanate complex. This complex gives a maximum absorbance at a wavelength of 500 nm. The results have demonstrated very high total antioxidant capacity when compared with the standards: BHT, ascorbic acid and resorcinol.

Figure 6.Total antioxidant capacity of the extracts.

Additionally phytochemical analysis of the samples:

total fenolic and flavanoid content determination were investigated. Total fenolic compound determination is based on electron transfer of phenolic and reducing compounds of the samples to the molybdenum. The resulting blue colored complex can be determined at a wavelength of 760 nm and the results are given as gallic acid equivalents.The total flavanoid content was determined from the plot drawn with absorbance values measured at different concentrations of quercetin. The values for gallic acid equivalent of phenolic compounds and quercetin equivalent of flavonoids were determined as quite high.

Table 1.Total phenolic and flavanoid content of the extracts.

*GAE: Gallic acid equivalent, r2: 0.9967, QE: Quercetin equivalent, r2: 0.9351.

CONCLUSION

According to the all antioxidant assays and phenolic and flavanoid contents experiments of the plant roots, we can mention the high antioxidative properties of the roots of the plant. The equivalent amounts of total phenolic and total flavonoid components are higher than expected and this supports high level of antioxidant test results.As a result, it has been proved of Urtica urens roots growing in the Blacksea region of Turkey: Giresun-Demirci plateu have high antioxidant activity verifying its notability as a folk medicine.

ACKNOWLEDGEMENTS

We are grateful for financial support by the Ordu University, Scientific Research Projects Coordination Department; Project no: AR-1529 and the authors are thankfull to the Central Research Laboratory of Amasya University for spectrophotometric work.

REFERENCES 1Abdel-Wahhab, M.A.; Said, A.; Huefner, A. Pharm. Biol. 2005, 43, 515–525. 2Kopyt’ko, Y.F.; Lapinskaya, E.S.; Sokol’skaya, T.A. Pharm. Chem. J. 2012, 45, 622-631. 3Marrassini, C.; Davicino, R.; Acevedo, C.; Anesini, C.; Gorzalczany, S.; Ferraro, G. J. Nat. Prod. 2011, 74, 1503–1507. 4Bourgeois, C.; Leclerc, E.A.; Corbin, C.; Doussot, J.; Serrano, V.; Vanier, J.R.; Seigneuret, J.M.; Auguin, D.; Pichon, C.; Lain, E.; Hano, C. C. R. Chimie, 2016, 19, 1090-1100. 5Lapinskaya, E.S.; Kopyt’ko, Y.F.; Timokhina, E.A.; Krapivkin, B.A.;

Levandovskii, G.S.; Dargaeva, T.D.; Sokol’skaya, T.A. Pharm. Chem. J. 2008, 42, 650-653. 6Ozkarsli, M.; Sevim, H.; Sen, A. Xenobiotica, 2008, 38, 48–61. 7https://togoagatewards.wordpress.com/2013/05/27/herbalism-stinging-nettle/ 8Dampc, A.; Luczkiewicz, M. Fitoterapia, 2013, 85 130–143. 9Steenkamp, V., Mathivhaa, E., Gouws, M. C., van Rensburg, C. E. J. J. Ethnopharmacol. 2004, 95, 353–357. 10Kumar H.M.; Prathima V.R.; Sowmya; Siddagangaiah; Thribhuvan, K.R.Int. Res. J. Pharm. App Sci.2013, 3, 112-119. 11Steenkamp, V.; Mathivhaa, E.; Gouws, M. C.; van Rensburg, C. E. J. J. Ethnopharm.2004, 95, 353–357. 12Manu Kumar, H. M.; Prathima, V. R.; Siddagangaiah, S. Int. Res. J. Pharm. App. Sci.2013, 3, 112-119. 13Brand-Williams, W.; Cuvelier, M. E.; Berset, C. LWT-Food Sci. Tech.1995, 28, 25-30. 14Oyaizu, M. Jpn. J. Nutr.1986, 44, 307-315. 15Decker, E. A.; Welch, B. J. Agric.Food Chem.1990, 38, 674-677. 16Nishikimi, M.; Rao, N. A.; Yagi, K. Biochem. Biophys. Res. Commun. 1972, 46, 849–854. 17Gulcin, I.; Kufrevioglu, O. I.; Oktay, M.; Buyukokuroglu, M. E.;J. Ethnopharm.2004, 90, 205–215. 18Woraratphoku J; Intarapichet K. O.; Indrapichate A. Food Chem. 2007, 104, 1485-1490. 19Zhishen, J.; Mengcheng, T.; Jianming, W. Food Chem. 1999, 64, 555−559.


Structural, Electronic, Elastic and Vibrational Properties of Spinel

MgIn2O4 and ZnIn2O4: A First-principles Study

Ahmet İYİGÖRa, Mustafa ÖZDURANb, Abdullah CANDANa

aCentral Research and Practice Laboratory (AHİLAB), Ahi Evran University, TR-40100 Kırşehir, Turkey

bDepartment of Physics, Faculty of Arts and Sciences, Ahi Evran University, TR-40100 Kırşehir, Turkey *e-mail corresponding author:[email protected]

Keywords:Spinel oxides, structural properties, elastic properties.

INTRODUCTION

MgIn2O4 and ZnIn2O4belong to an interesting family of

spineloxides that is an importantsemiconductor

compounds.Spinel MgIn2O4 and ZnIn2O4compounds are

promising material for high frequency devices [1],

magnetic cores [2] and superconductors [3, 4].

ThespineloxidesAB2O4, whereA= Mg andZn, B=In,

crystallize in a closed-packedface-centered-

cubicstructure, spacegroupFd-3m (No. 227) [5].

The AIn2O4 (A=Mg, Zn) spinel oxides have been the

subject of many theoretical and experimental studies [1-

17]. Theoretically, using the full-potential linearized

augmented plane-wave plus local orbitals

(FPLAPW+lo) method based on the density functional

theory (DFT), Zerarga et al. [1, 6] reported the

structural, electronic, elastic, thermodynamicand optical

properties of spinel oxidesZnAl2O4, ZnGa2O4and

ZnIn2O4. Elastic and structuralproperties under pressure

of MgX2O4(X= Al, Ga, In)have been investigated using

ab initiomethod by Bouhemadou et al. [4].The

aforementioned authors calculated the electronic band

profile and the optical response of spinel MgIn2O4

through the Tran–Blaha-modified Becke–Johnson

density functional [17].

Ueda et. al. [8] performed a experimental study on band

gap and high electroconductivity of MgIn2O4 spinel

oxide.Besides, the lattice parameters and band gap of

cubic spinelMgIn2O4compound have been calculated

using by Esther et al. [12] using powder X-ray powder

diffraction (XRD) and solid state reaction (SSR).

Method

All the calculations have been performed using the

plane-wave pseudo-potential DFT method implemented

in the MedeA-VASP package [18, 19]. Projector

Augmented Wave (PAW) pseudo-potentials were used

to present the ionic potentials. The Perdew–Burke–

Ernzerhof (PBE) [20] exchange-correlation functional

was treated at the generalized gradient approximation

(GGA). In fact, the calculated results of GGA (PAW-

PBE) are in reasonable agreement with the experimental

values in all cases, this shows that the pseudo-potential

and our methods are suitable for this study.The Mg

(2p63s2), Zn (3p63d104s2), In (4p64d105s25p1)and O

(2s22p6) states are treated as valence electrons.

According to a careful checking the convergence of

total energy with respect to the energy cut-off of plane

wave and the size of k-mesh, the plane-wave basis set

energy cut-off was set at 510 eV in all calculations.


The Monkhorst-Pack [21] scheme k-points grid

sampling was set at 5 for the Brillouin zone. The Fermi

distribution function with a smearing parameter of 0.2

eV was used to integrate the bands at Fermi level [22].

Phonon dispersion curves are calculated using the

MedeA-PHONON [23] module with the forces

calculated with the Vasp.


The spinel structure is characterized by twofree

structure parameters: the lattice parameter a0 and

internal oxygen parameteru. The Mg, Zn atoms are

located at the Wyckoff positions 8a (0.125, 0.125,0.125)

tetrahedral sites, whereas In atomis located at the

16d(0.5, 0.5, 0.5) octahedral sites and the O atoms at

32e (u, u, u) of an face-centered-cubic

(FCC)latticestructure (see Fig. 1).

Figure 1. The unit cell of the cubic spinel MgIn2O4 and ZnIn2O4.

In Table 1, we summarize our calculated equilibrium

lattice constant a0 and internal structural parameter u of

MgIn2O4 and ZnIn2O4 compared with the available data

in the literature. The optimized lattice constants (a0) of

MgIn2O4 and ZnIn2O4 are 9.0485 Å, and 9.0553 Å,

respectively. On the other hand, the internal structural

(u) parameters are 0.2556for MgIn2O4 and 0.2562for

ZnIn2O4. There is a good agreement between our results

and that previously reported [1, 2, 4]. Our calculated

values of the lattice constants for MgIn2O4 and ZnIn2O4

deviate by about 0.92% and 0.23%, respectively, from

those reported in Ref. (4-GGA, 2). Moreover, calculated

values of the internal structural parameters for MgIn2O4

and ZnIn2O4 deviate by about 0.19% and 0.27% [4-

GGA, 2].

Table 1.Calculated lattice constant (a0) and internal structural parameter (u) of spinel MgIn2O4andZnIn2O4compounds.

The calculated band structures along the high symmetry

directions in the Brillouin zone are depicted Fig. 2 and

Fig. 3. The valence band maximum (VBM) and the

conduction band minimum (CBM) occur at Γ point,

making MgIn2O4 and ZnIn2O4compounds to be a direct

band gap materials (Γ–Γ). The results for the electronic

band structures are in good agreement with the existing

calculations reported in the literature [1, 5, 17]. The

calculated direct band gaps (Γ–Γ, L–L, X–X, K–K and

W–W) and indirect band gaps (Γ–L and Γ–K) for the

considered compounds are given in Table 2 along with

the available theoretical and experimental results [1, 5,

7, 8, 12, 17]. The computed direct band gapsat the Γ

point of MgIn2O4 and ZnIn2O4are equal to 1.71 eV and

1.32 eV, respectively.

Elastic constants of a solid are important because they

are closely related to various fundamental solid-

statephenomena such as phonon spectra, specific heat,

thermal expansion, Debye temperature, interatomic

bonding,equations of state, sound velocities and fracture

toughness.

Compounds References a0 (Å) u

MgIn2O4

Present 9.0485 0.2556 [4-GGA] 9.1022 0.2561 [4-LDA] 8.9447 0.2558 [12-Exp.] 8.86 - [15-Exp.] 8.8100 0.2570

ZnIn2O4

Present 9.0553 0.2562 [1] 9.092 0.2555 [2] 9.076 0.2555 [5] 8.8424 0.2557 [6] 8.869 0.2547 [7] 8.9297 0.2558

[13] 8.868 0.2653 [14-Exp.] 8.8370 0.2608


Figure 2. The electronic band structure for spinel MgIn2O4along the high symmetry directions in the Brillouin zone.

Figure 3. The electronic band structure for spinel

ZnIn2O4along the high symmetry directions in the Brillouin zone.

In cubic compounds, there are only three

independentelastic constants.Hence, we have computed

the elastic constants of MgIn2O4andZnIn2O4 compounds

using the stress-finitestraintechnique. They are

compared together with data available from other

calculations and listed in Table 3 [1, 2, 4-6].Our

estimation of bulk modulus of 142.95 GPa is bigger

than the calculated value using GGAapproximation (125

GPa) for MgIn2O4 [4-GGA]. Mechanical stability of

thesecompound has been analysed in terms of their

elastic constants. The conditions formechanical stability

for cubic crystals are given by[24]

C11 > 0 , 𝐵 > 0 , C11 − C12 > 0

The obtained elastic constants for

MgIn2O4andZnIn2O4satisfy these mechanical stability

criterions, indicating that these compounds are

mechanical stable in cubic structure.

Table 2. Calculated some direct band gaps (Γ-Γ, L-L, X-X, K-K ve W-W) and indirect band gaps (Γ-L and Γ-K) for MgIn2O4 and ZnIn2O4 spinel compounds.

Compounds References 𝚪 − 𝚪 L-L X-X K-K W-W 𝚪 − 𝐋 𝚪 − 𝐊

MgIn2O4

This study 1.71 4.20 5.11 5.12 5.58 4.15 5.06 [8-Exp.] 3.4 - - - - - - [12-Exp.] 3.1 - - - - - - [17-GGA] 2.38 - - - - - - [17-LDA] 2.2 - - - - - - [17-mBJ] 2.81 - - - - - -

ZnIn2O4

This study 1.32 3.96 4.96 4.90 5.30 3.99 4.93 [1-GGA] 1.009 3.687 4.565 4.575 4.915 1.052 1.081

[1-GGA-EV] 1.817 4.282 5.091 5.087 5.400 1.850 1.878 [5] 1.39 - - - - - - [7] 1.12 - - - - - -

Table 3.Calculated Bulk modulus (B), elastic constants (Cij), shear modulus (G), ratio of B/G and Young’s modulus (E) of MgIn2O4andZnIn2O4compounds.

Compounds References B (GPa) C11 (GPa) C12 (GPa) C44 (GPa) G(GPa) B/G E (GPa)

MgIn2O4 Present 142.95 242.16 93.34 74.77 74.62 1.92 190.69

[4-GGA] 125 182 96 68 - - 115 [4-LDA] 147 213 114 71 - - 134

ZnIn2O4

Present 145.27 247.35 94.24 72.24 73.96 1.29 189.63 [1] 148.70 - - - - - - [2] 123 189 85 68 - - 146 [5] 163 - - - - - - [6] 182.43 331.95 107.66 112.93 112.61 1.62 280.18


Figure 4.The phonon dispersion curve for MgIn2O4 along the high symmetry directions in the Brillouin zone.

Figure 5.The phonon dispersion curve for ZnIn2O4 along the high symmetry directions in the Brillouin zone.

In Fig. 3, the calculated phonon dispersion curves are

shown along several high-symmetry lines in the

Brillouin Zone. The phonon properties of

AIn2O4(A=Mg, Zn) compounds are calculated within

the generalizedgradient approximation (GGA) in the

spinel structure, with space group symmetry Fd-3m

(#227). The calculatedphonon dispersion curves of

AIn2O4(A=Mg, Zn) confirm that two compounds are

dynamically stable in thespinel structure without any

imaginary phonon frequencies.

CONCLUSION

In this study, the structural, electronic, elastic and

vibrational properties in the considered structures of

AIn2O4 (A=Mg, Zn) spinel oxides are presented using

first-principle calculations. The obtained structural

parameters and elastic properties are in good agreement

with available theoretical and experimental results.

From the obtained elastic constants, we have analyzed

its mechanical stability and some important physical

quantities, such as Bulk, Young’s and Shear moduli,

B/G ratios. Phonon dispersion curves confirm their

dynamical stability in cubic spinel structure.

ACKNOWLEDGEMENTS

This work was supported by the Ahi Evran University

Scientific Research Projects Coordination Unit. Project

Number: FEF.A3.16.022.

REFERENCES 1Zerarga, F., Bouhemadou, A., Khenata, R., & Bin-Omran, S., Solid StateSciences2011, 13(8), 1638-1648. 2Bouhemadou, A.,&Khenata, R., PhysicsLetters A 2006, 360(2), 339-343. 3Candan, A.,and Uğur, G, Modern PhysicsLetters B 2016, 30(03), 1650002. 4Bouhemadou, A.,Khenata, R., &Zerarga, F., TheEuropeanPhysicalJournal B 2007, 56(1), 1-5. 5Karazhanov, S. Z.,&Ravindran, P., Journal of theAmericanCeramicSociety2010, 93(10), 3335-3341. 6Zerarga, F.,Bouhemadou, A., Khenata, R., & Bin-Omran, S., ComputationalMaterialsScience2011, 50(9), 2651-2657. 7Dixit, H.,Tandon, N., Cottenier, S., Saniz, R., Lamoen, D., Partoens, B., Van Speybroeck, V., andWaroquier, M., New Journal of Physics2011, 13(6), 063002. 8Ueda, N.,Omata, T., Hikuma, N., Ueda, K., Mizoguchi, H., Hashimoto, T., &Kawazoe, H., AppliedPhysicsLetters1992, 61(16), 1954-1955. 9Kawazoe, H.,&Ueda, K., Journal of theAmericanCeramicSociety1999, 82(12), 3330-3336. 10Seko, A.,Yuge, K., Oba, F., Kuwabara, A., &Tanaka, I., PhysicalReview B 2006, 73(18), 184117. 11Krishna, K. M.,Nisha, M., Reshmi, R., Manoj, R., Asha, A. S., &Jayaraj, M. K., 2008. 12Esther Dali, S.,SaiSundar, V. V. S. S., Jayachandran, M., &Chockalingam, M. J., Journal of MaterialsScienceLetters1998, 17(8), 619-623. 13Wei, S. H.,&Zhang, S. B., PhysicalReview B 2001, 63(4), 045112. 14Inorganic CrystalStructure Database; GmelinInstitut, Karlsruhe, 2001. 15Hill, R. J.,Craig, J. R., &Gibbs, G. V., PhysicsandChemistry of Minerals1979, 4(4), 317-339. 16Jiang, C.,Sickafus, K. E., Stanek, C. R., Rudin, S. P., &Uberuaga, B. P., PhysicalReview B 2012, 86(2), 024203. 17Manzar, A., Murtaza, G., Khenata, R., &Muhammad, S., ChinesePhysicsLetters2013, 30(6), 067401. 18Kresse, G. and Hafner, J., Phys. Rev. B 1993, 47:558. 19Kresse, G. and Furthmuller, J., Phys. Rev. B 1993, 54:1169. 20Perdew, J. P.; Burke K. and Ernzerhof, M., Phys. Rev. Lett. 1996, 77:3865. 21Monkhorst, H. J. and Pack, J. D., Phys. Rev. B, 1976, 13:5188. 22Methfessel, M.; Paxton, A.T., Phys. Rev. B 1989, 40:3616. 23Parlinski, K., Li, Z. Q., & Kawazoe, Y., Physical Review Letters 1997, 78(21), 4063. 24Born, M. and Huang, K., in Dynamical Theory of Crystal Lattices 1954.


First-Principle Study of the Structural and Mechanical Properties of

RuTi Compound

Osman ÖRNEK*

Ahi Evran Üniversitesi, Mühendislik Mimarlık Fakültesi, Metalürji ve Malzeme Mühendisliği Bölümü Kırşehir-

TURKEY

[email protected]

Keywords: DFT, Intermetallic, band structure, phonon, elastic properties

INTRODUCTION

Ruthenium can be considered the most reactive element in platinum group-metals. The most important characteristic for practical applications is an excellent catalytic activity [1]. Ruthenium is extensively used as an alloying agent in applications for the chemical and electronics industries [2].The phase relations and the thermodynamic description of the Ru–Ti system have been investigated by Gao et al. [3]. The Ru-Ti system phase diagrams have been studied by Eremenko et al.[4] and Boriskina and Kornilov [5], and Raub and Roeschel [6]. The structural, elastic and electronic properties of RuTi intermetallic compound in the B2 phase have been investigated using the FP-LAPW method as implemented in WIEN2k code by Jain et al. [7]. Jahnatek et al. [8] has performed a study of ruthenium binary systems with 28 transition metals, using first principle calculations. This work is to investigate the structural, electronic, elastic and phonon properties of RuTi in the B2 phase by employing the DFT. The phonon properties are necessary for a microscopic understanding of the lattice dynamics. The knowledge of the phonon spectrum plays a significant role in determining various material properties such as phase transition, thermodynamic stability, transport and thermal properties..

METHOD

The calculations were performed using the Quantum-ESPRESSO program package [9]. The program was based on the density functional theory and plane-wave basis set. The electronic exchange correlation potential was calculated by the generalized gradient approximation (GGA) using the scheme of Perdew–

Burke–Ernzerhof (PBE) [10]. Electron–ion interaction was represented by the ultrasoft Vanderbilt

pseudopotential [11]. The wave functions were expanded into plane waves with kinetic energies of up to 40 Ryd. The electronic charge density was evaluated up to the kinetic energy cut-off of 400 Ry. Brillouin-zone integrations were performed using a 10x10x10 k-point mesh. Integration up to the Fermi surface was done using the smearing technique [12] with smearing parameter being 0.02 Ry. Having obtained self-consistent solutions of Kohn–Sham equations, the lattice-dynamical properties were calculated within the framework of the self-consistent density functional perturbation theory [13, 14]. To obtain complete phonon dispersions and density of states, eight dynamical matrices were calculated on a 4x4x4 q-point mesh. The dynamical matrices at arbitrary wave vectors can be evaluated by means of a Fourier deconvolution on this mesh. The elastic constants can be obtained by calculating the total energy as a function of volume-conserving strains that break the cubic symmetry. The bulk modulus B, C44, and shear modulus C’ = (C11- C12)/2are calculated from hydrostatic pressure e e = (,,,0,0, 0), tri-axial shear strain e = (0, 0, 0,,,)and volume-conserving orthorhombic strain e = (,, (1 + )-2-1, 0, 0, 0), respectively [15].


The binary intermetallic RuTi compound has been examined in the B2 (CsCl) phase. The two atoms have coordinates τRu=(0, 0, 0) and τTi=(0.5, 0.5, 0.5). The ground state properties of RuTi have been studied using its calculated total energies. The calculated total energies have been fitted to the Murnaghan equation of state [16] to obtain equilibrium lattice constant and other structural properties. The obtained values of a0, B and B' for the RuTi compound are tabulated in Table 1 along with the existing theoretical and experimental data.


The elastic properties of a cubic single crystal are completely defined by three independents elastic constants, namely C11, C12 and C44, and the mechanical stability conditions are C11+C12>0, C44>0, and C11–

C12>0. The experimental values of the elastic constants of RuTi compound are not available in the literature.The brittleness and ductility properties of RuTi compound have been investigated by calculating the B/G. The critical value that separates brittleness and ductility is around 1.75. If B/G value is smaller than 1.75, the material behaves in a brittle manner; otherwise, the material is a ductile compound. The B/G value of RuTi in B2 phase is 3.723. According to this empirical law, the RuTi compound is a ductile material. The band structures of the B2 phase of RuTi as well as the high symmetry directions in the simple cubic Brillouin-zone (BZ), calculated by using the generalized gradient approximation (GGA), are shown in figure 1, in which EF= 0 is taken. The band profiles of RuTi compound are in good agreement with the earlier work [7]. This exhibits normal metallic behaviour with bands crossing the Fermi level along various directions, which results in a finite DOS at the Fermi level, as shown in figure 1. The character of the band states for this compound has been identified by calculating their total and partial densities of states (DOS) in figure 2. It is seen that there is no gap at the Fermi level and the total

density of state (DOS), which is 0.746 𝑠𝑡𝑎𝑡𝑒𝑠

𝑒𝑉 𝑐𝑒𝑙𝑙 for RuTi.

The results indicate that the predominant contributions of the density of states at the Fermi level come from the

Ti 3d and Ru 4d states for RuTi. From the calculated total density of states of RuTi compound, it can be seen that there is one peak below the Fermi level. This peak is cantered -3.7 eV, which is mainly dominated by the Ru 4d state. In addition, there is a peak above the Fermi level for this compound. This peak comes from Ti 3d states.

Figure1 Electronic band structure of RuTi in the B2 phase.

Figure 2 Total and partial of states for in the RuTi B2 structure

Table 1 Calculated lattice constants (in Å), bulk modulus (in GPa) and pressure derivative of the bulk modulus and elastic constants for RuTi in the B2 phase.

Referances a(Å) B dB/dP B C11 C12 C44 G B/G RuTi This Work 3.076 215.8 4.23 231.255 453.482 129.14 92.838 116.971 3.723 VASP [2] 3.598 -- LMTO [3] 3.51 VASP [1] 3.514 Exp.[9] 3.55

CONCLUSION

In this paper, structural, electronic, elastic, thermodynamic and phonon properties of Co3V compound in the L12 phase has been studied by DFT. The structural properties including lattice constant, bulk modulus and first-order pressure derivative of the bulk modulus have been calculated and compared available data. I have also studied the mechanical properties of Co3V. The elastic constants have been calculated using the approach, the energy-strain method. The calculated elastic constants satisfy the mechanical stability criterion and the brittle of Co3V in the L12 phase is predicted by Pugh’s

criterion. The obtained values of B/G ratio for Co3V are in reasonable agreement with those obtained previously.

The electronic structure calculation showed that Co3V exhibits metallic character. The electronic results indicate that the predominant contributions of the density of states at the Fermi level come from the Co 3d state for this compound.

ACKNOWLEDGEMENTS

This work was supported by the Ahi Evran University Scientific Research Projects Coordination Unit. Project Number: MMF.E2.16.001.


REFERENCES 1Hartley F.R .; The occurrence, extraction, properties and uses of the platinum group metals, in the chemistry of the platinum group metals, recent developments. Amsterdam: Elsevier; 1991,9. 2Loferski,P.J.;Minerals yearbook-platinum group metals. Washington, DC: US Geological Survey.2008. 3Gao,Y.;Guo,C.;Li, C.; Cui, S.; Du, Z.; Journal of Alloys and

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Synthesis and Characterization of p-Chlorobenzoylthiourea Amino

Acid Derivatives

RamizahRAMLIa, SitiKamilah CHE SOHb, NurzianaNGAHc&M. Sukeri M. YUSOFa*

aSchool of Fundamental Science, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia bSchool of Marine and Environmental Sciences, Universiti Malaysia Terengganu, 21030, Kuala Terengganu, Terengganu,

Malaysia cDepartment of Chemistry, Kuliyyah of Science, IIUM, Kuantan Campus, 25200 Kuantan, Pahang, Malaysia

*E-mail corresponding author: [email protected]

Keywords: Synthesis, condensation reaction,chlorobenzoylthiourea derivatives, amino acid, valine

INTRODUCTION

Over one decade ago, an organic compound

consists of carbon, hydrogen, nitrogen and sulphur atom have been introduced and was name as thiourea, SC(NH2)2. Since then, numerous numbers of thiourea and their derivatives have been synthesized1-7. Thiourea derivatives were extremely versatile compounds. Thanks to the major roles played by the nitrogen, oxygen and sulphur atoms, thiourea derivatives have able to coordinate to the metal atoms forming many stable coordination complexes8-12. The diverse applications offered by thiourea derivatives such as antibacterial agents13-15, antiamoebic agents16, reducing agent17, corrosion inhibitors18-19, chromogenic sensor20, thin film21 and organocatalyst22have greatly amazed a lot of scientists.

Amongthedifferent types of thiourea

derivatives synthesized previously, benzoylthiourea derivatives have received tremendous attentions. The ortho-, meta- and para- substitution at the phenyl ring of the benzoyl moiety have always become one hot topic of studies among the researchers. However, the research design involving substituted-benzoylthiourea and amino acid were very few reported. Taking this matter into consideration, three new compounds were synthesized from the reaction of o/m/p-chlorobenzoyl isothiocyanate with valine. The effect of isomer positions was studied through the IR, UV-Vis and NMR spectroscopies. Scheme 1 referred to the molecular structure of the synthesized compound.

Scheme1. Structure of 2-(3-(2/3/4-chlorobenzoyl)thioureido)-3-methylbutanoic acid


Structural elucidation of compounds C1, C2 and C3 were carried out using FT-IR, UV-Vis and NMR data analysis. The IR spectra of the synthesized compounds revealed the existence N-H, O-H, C=O-OH, C=O-NH, C=C and C=S vibrational modes. The N-H absorption for C1, C2 and C3 were recorded at 3241.90 cm-1, 3188.89 cm-1 and 3270.61 cm-1, respectively which were in close accord to the literature23. The wavenumber recorded for C3 was higher than for C1 and C2. Yusof et al.,2010explained that the NH stretching frequencies range were affected by the position of NHC(S)NHC(O) group vibrations and also the stabilization effect of hydrogen bonding24. The O-H stretching was observed at 3183.20 cm-1, 3063.63 cm-1 and 3172.26 cm-1 for C1, C2 and C3 and were in agreement with previous values25.

The two carbonyl stretching were strongly

absorbed within the range of 1670-1720 cm-1. The C=O of carboxylic acid appeared at higher wavenumber at 1719.44 cm-1, 1716.65 cm-1 and 1710.92 cm-1 for C1, C2 and C3, respectively because greater electronegativity of oxygen compared to nitrogen next to the carbonyl group26. At slightly lower wavenumber,


the C=O stretching of amide for C1, C2 and C3 were seen at 1672.02 cm-1, 1682.46 cm-1 and 1671.08 cm-

1,respectively27. Formation of the conjugated resonances of the phenyl with the carbonyl group and the effect of intramolecular hydrogen bonding with the amide proton have caused the absorption band to appear at slightly lower wavenumber28. The C=C stretching of the phenyl ring were found in the range of 1546-1560 cm-129, the thione group was recorded at the wavenumber ca. 746-758 cm-1 and the results agreed with previous literature30. The wavenumber recorded for the C=S stretchingis much lower than C=O stretching due to the greater mass of sulfur atom compared to the oxygen atom31.The FT-IR data is presented in Table 1. Table 1. FT-IR Data for C1, C2 and C3

Wavenumber (cm-1) Absorption

band C1 C2 C3

v(N-H) 3241.90 (m)

3188.89 (s)

3270.61 (m)

v(O-H) 3183.20 (s)

3063.63 (s)

3172.26 (m)

v(C=O-OH) 1719.44 (s)

1716.65 (s)

1710.92 (s)

v(C=O-NH) 1672.02 (s)

1682.46 (s)

1671.08 (s)

v(C=C) 1560.01 (s)

1546.84 (s)

1548.33 (s)

v(C=S) 748.15 (m)

756.97 (m)

757.65 (m)

The UV-Vs spectra for compounds C1 and C2

were recorded at a concentration of 1.0 E-5 M, while compound C3 was recorded at 1 E-4 M. The methanol cut-off were observed at 201.2 nm, 204.4 nm and 201.0 nm respectively for C1, C2 and C3.

In overall, one to two absorption bands were

displayed by the UV spectra of chlorobenzoylthiourea amino acid derivatives. Compound C1 and C2 showed the appearance of primary and secondary absorption band at 230.0 nm, 241.8 nm and 279.5 nm, 285.4 nm, respectively. This two bands arised from the n-* and -* transitions. The bands were corresponded to the C=O and C=S functional groups, respectively32. Compound C3 only have one broad absorption band observed in the spectra observed at max 248.0 nm. The broad band was resulted from the overlapping of the two electronic transitions of n-* and -* from the C=O and C=S group.

The effect of o-/m-/p- position isomer have

slightly affected the wavelength of the primary absorption band of the C=O group. Compound C1 with ortho isomer have the absorption of C=O group appeared at the lowest wavelength compared to C2 and C3. The absorption band were recorded at max 230.0

nm, 241.8 nm and 248.0 nm respectively33.The highest steric effect of the chloro substituent in C1 contributed to the lower wavelength region.The maximum bathochromic effect exerted by the para isomer of C3 move the primary absorption band to the red shift, caused it to overlapped with the secondary absorption band34. The UV-Vis data can be referred in the Table 2. Table 2. UV-Vis Data for C1, C2 and C3

Code Wavelength (max, nm)/ Extinction coefficient

(, L/mol/cm)

Possible assignment

C1 201.2 (93510) 230.0 (shoulder) 279.5 (28210)

MeOH cut-off n-* and -* n-* and -*

C2 204.4 (47700) 241.8 (23800) 285.4 (12500)

MeOH cut-off n-* and -* n-* and -*

C3 201.0 (3340) 248.0 (2090)

MeOH cut-off n-* and -*

The proposed molecular structures for the synthesized compounds were supported by the NMR data obtained. The methyl protons for all compounds wereassigned in the range of δH0.91-0.98 ppm. The two methine protons appeared as doublet of doublet at the wavenumber of approximately ~2.3ppm and ~4.8 ppm for all compounds. The hydroxyl proton of C=O-OH group was absence in the 1H NMR spectra which probably due to the easily dissociated of hydroxyl proton. The methyl carbons appeared at δC 18.4-19.11 ppm. The methine carbons on the other hand were observed at the higher field region in the 13C NMR spectra, recorded at around ~30.6 ppm and ~63.0 ppm. The carbon signals for C=O-OH group for all three compounds were appeared at the wavenumber ca. 171.8 ppm and were supported by previous literature35. With the methyl, methine and carboxylic acid resonances presence in the spectra, it proved that valine (amino acid) existed in the synthesized compounds. The aromatic protons were assigned to the resonances appeared at δH7-8 ppm. Compounds C1 and C2 show four resonances corresponded to four protons attached to the phenyl ring. Compound C3 appeared as pseudo-doublet with two resonances at δH 7.59 ppm and 7.69 ppm due to the presence ofchloro group at para position. For 13C NMR spectra, the six carbons of the phenyl ring were presence at δC127-138 ppm. The C=O signal next to the phenyl ring and amide group (C=O-NH) were found at δC168 ppm. The signal appeared at the downfield region due to the effect of electronegative oxygen atom and the intramolecular hydrogen bonding36. It is thus proved that, benzoyl group was part of the compounds with aromatic and carbonyl groups presence.


The presence of the corresponding amide

proton, N-H and thione carbon, C=S resonances were very important in order to confirm the successfully synthesized of the compounds. In the 1H NMR spectra, the two amide protons were observed at the downfield region due to the resonance effect and hydrogen bond formation37. The C=S-NH signals were assigned at δH

11.07 ppm, 11.27 ppm and 11.30 ppmfor compoundsC1, C2 and C3,respectively. The other amide proton which have two electronegative groups C=O and C=S next to it, were appeared slightly deshielded at δH 11.98 ppm, 11.76 ppm and 11.70 ppm for each of the compounds. The thione groups (C=S) were observed far downfield in the 13C NMR spectra probably due to the lower excitation energy π-π* based on the literature38. The signals resonated at δC 180.88 ppm, 181.21 ppm and 181.29 ppm were assigned to the thione groups in agreement with previous literature39. With the NH and C=S signals detected in the spectra, it proved that the synthesized compounds were definitely thiourea derivatives.

From the NMR analysis, the presence of amino acid, benzoyl and thiourea moieties have thus confirmed the product asbenzoylthiourea amino acid derivatives. The NMR data is depicted in Table 3. Table 3. 1H and 13C NMR Data for C1, C2 and C3

Compounds Signal C1

δ, ppm C2

δ, ppm C3

δ, ppm C=O-NH 11.98 (1H) 11.76 (1H) 11.70 (1H) C=S-NH 11.07 (1H) 11.27 (1H) 11.30 (1H)

Ar-H 7.52-7.61 (4H)

7.55-8.02 (4H)

7.59 (2H), 7.69 (2H)

CH 2.31 (1H), 4.86 (1H)

2.29 (1H), 4.86 (1H)

2.31 (1H), 4.86 (1H)

CH3 0.91(1H) 0.98 (1H) 0.98 (1H) C=S 180.88 181.21 181.29

C=O-OH 171.86 171.88 171.88 C=O-NH 168.64 167.94 168.25

Ar-C 127.56-134.64

127.90-134.53 128.98-138.49

CH 30.63, 62.93

30.58, 63.00

30.59, 62.97

CH3 18.54, 19.08

18.54, 19.08

18.45, 19.11

CONCLUSION

In conclusion, three new compounds namely2-(3-(2-chlorobenzoyl)thioureido)-3-methylbutanoic acid, 2-(3-(3-chlorobenzoyl)thioureido)-3-methylbutanoic acid and 2-(3-(4-chlorobenzoyl)thioureido)-3-methylbutanoic acid were obtained using condensation reaction. The proposed structures of the compounds were confirmed via IR, UV-Vis and NMR analyses. Different positions of chloro subtituent attached to the

phenyl ring have affected the IR, UV and the NMR spectral data obtained.

ACKNOWLEDGEMENTS

The authors would like to show appreciation to

the Universiti Malaysia Terengganu and IIUM Kuantan Campus for the research facilities provided and for the huge contribution towards this research project.

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Structural, Elastic and Electronic Properties of Fe2TiSi Full-Heusler Compound

Mustafa ÖZDURAN and Raşit UMUCU

Ahi Evran Üniversitesi Fen Edebiyat Fakültesi, Fizik Bölümü, 40100-Bağbaşı-Kırşehir/TURKEY

*corresponding author:[email protected]

Keywords:Heusler alloys, density-functional theory, electronic structure.

INTRODUCTION

Heusler alloys have attracted great interest during the past decades because of their possible applications in spintronics or magnetoelectronics [1, 2]. The first Heusler alloys studied were crystallized in an L21structure which consists of four fccsublattices. Ideally these alloys have composition X2YZ. In general X and Y are transition metals and Z is a B-subgroup element. Yabuuchi et al. [3] have been studied for the electronic and transport properties of Fe2TiSi alloy in the L21 phase. They have observed that this material is non-magnetic alloy. Mienert et al. [4] have prepared the single-phase film of the full-Heusler compound Fe2TiSi alloy using magnetron sputtering. They have found to be a semiconductor with a gap of 0.4 eV. The structural identification of full Heusler Fe2TiSi alloy was measured using X-ray powder diffraction (XRD) by Raghavan [5]. Although considerable progress has been made in theoretically describing the structural and electronic properties of Fe2TiSi alloy, many of elastic properties of this material are still not well established. This paper is organized as follows. In Sec. II, we describe our calculational methods, and Sec. III is devoted to the discussion of the results of our calculations for the structural and elastic properties of Fe2TiSi Heusler alloy, including a comparison with previous available data. The electronic structure of this alloy is examined. A conclusion is provided in Sec. IV. Method The calculations were performed to obtain the structural, electronic and elastic properties of Fe2TiSi using first-principles calculations based on the density-

functional theory (DFT) within the generalized gradient approximation (GGA) as implemented in the Vasp-MedeA package [6, 7]. Plane-wave energy cut-off of 260 eV were used in VASP calculation. The k-points samplings were 5x5x5 for VASP in the Brillouin zone for Fe2TiSi, according to the Monkhorst–Pack scheme [8]. The structure was relaxed until the convergence in energy of 1x10−5eV was reached. In the VASP calculations, the Methfessel–Paxton smearing [9] with broadening of 0.225 eV was used for relaxation.


We calculated the ground state lattice parameters of Fe2TiSi alloy and compared this with the available experimental and theoretical values [3-5]. The computed values of lattice constants, bulk modulus, Shear and Young modulus, elastic constants and B/G ratios for the Fe2TiSi alloy in Table 1.


Table 1. Calculated lattice constants (in Å), Bulk modulu (in GPa), Shear and Young modulus (E, GPa), Poisson’s ratio () and elastic constantsCij(in GPa)for Fe2TiSi in the L21 phase.

Referances a(Å) B E C11 C12 C44 G B/G

Fe2TiSi This Work 5.684 190.682 0.194 349.826 441,3692 130,6772 140,544 146,465 1,302

GGA [3] 5.685

Exp.[4] 5.709

Theory [5] 5.717

Exp.[5] 5.720

The calculated lattice constant for Fe2TiSi are in good

agreement with the available theoretical and

experimental data. The elastic constants (Cij) are

valuable parameters for understanding how a material

behaves based on its structural stability and ductility

properties. There are three independent elastic

constants (C11, C12 and C44) in cubic crystals. The

conditions of stability reduce to a simple form: C11>0,

C12>0, C44> 0 and C11−C12> 0. The elastic constants of

the full-Heusler alloy Fe2TiSi are calculated using the

approximation reported in [10]. Unfortunately, there

are no experimental and theoretical data available in

the literature regarding the elastic constants of this

material. An important material parameter is the B/G

ratio, as an indication of ductility and brittleness.

According to the Pugh criteria [11], a high B/G ratio

indicates ductility, while a low B/G ratio indicates

brittleness. The critical value, separating ductile

materials from brittle ones, is 1.75. The B/G value is

1.302 for Fe2TiSi in the L21 phase. Figure1 shows the

electronic band structure of Fe2TiSi alloy in the L21

phase. This alloy is a semiconductor because there is a

gap at the Fermi level. The calculated value of the band

gap is found to be 0.46 eV. This value is in good

agreement with available data [3, 4]. Our calculated

band structures for Fe2TiSi alloy are in good agreement

with previously reported result [3].

Figure 1.The electronic band structure of Fe2TiSi in the L21 phase.

The character of the band states has been identified

using the calculated total and partial densities of states

for this alloy in Figure 2. The bands above the Fermi

level, are dominated by Fe-d states and Si-s states.On

the other hand, the bands below the Fermi level mainly

dominated by Fe-d states.

Figure 2. The total and projected density of states for Fe2TiSi in the L21 phase.


CONCLUSION

The structural, electronic and elastic properties of

Fe2TiSi have been investigated using the

pseudopotential plane-wave method. Our main results

and conclusions can be summarized as the calculated

structural properties (lattice constant and bulk

modulus) in the L21 phase, which are in good

agreement with the values reported in the literature.

The elastic constants of Fe2TiSi alloy have been

computed for first time using DFT. The electronic band

structures were calculated and compared in the

available data for this material, in the L21 phase.

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ACKNOWLEDGEMENTS This work was supported by the Ahi Evran University

Research Project Unit under Project No:

FEF.E2.16.001


First Principles Calculation of Ru2VGa and Ru2CrGa Heusler Alloys

Ahmet İYİGÖRa, Abdullah CANDANa, Mustafa ÖZDURANb

aCentral Research and Practice Laboratory (AHİLAB), Ahi Evran University, TR-40100 Kırşehir, Turkey bDepartment of Physics, Faculty of Arts and Sciences, Ahi Evran University, TR-40100 Kırşehir, Turkey


Keywords:Density Functional Theory, electronic band structure, elastic properties.

INTRODUCTION

Heusler alloys have been known since 100 years.

Friedrich Heusler found that additions of third group

elements turn CuMn alloy into a ferromagnetic material

[1]. Heusler alloys are ternary intermetallic compounds

that are structured as the stoichiometric composition

A2BC, where, A is usually a transition metal, such as

Cu, Fe, Ni, Co, Ru; B is usually Mn, Cr or V and C can

be Al, Ga, Ge, Si, Sn in L21 cubic crystal structure. The

main characteristic of half-metallicferromagnetsis a

different behavior in the two spin bands: while the

majority spin band shows a typical metallic behavior,

the minority spin band is semiconducting. Thus, the spin

polarization at the Fermi level is 100%, maximizing the

efficiency of spintronic devices [2-4]. Recently, these

alloys have attracted considerable interest because of

their intersting magnetic properties [3, 5]. Magnetic

susceptibility and permeability, magnetostriction, Curie

temperature and hysterisis curves studies of the Heusler

alloys are basic topics [6, 7]. The Ru2VGa have been the

subject of various theoretical and experimental studies

[8-11]. Theoretically, using the full-potential linearized

augmented plane-wave (FPLAPW) method based on the

density functional theory (DFT), Abbassa et al. [8]

reported the structural, electronic, elastic and thermal

properties for Ru2VGa1-xAlx (x=0, 0.25, 0.5, 0.75, 1).

On the experimental side, Ru2VGa alloy has been

synthesized for the first time by Mondal et al. [9]. The

lattice constant and electrical resistivity of the Ru2VGa

alloy have been calculated using powder X-ray powder

diffraction (XRD) by Mondal et al. [10]. They state that

the Ru2VGa alloy show high resistances compared to

standard metals and have low residual resistivity ratio.

Method

All the calculations have been performed using the

plane-wave pseudo-potential DFT method implemented

in the MedeA-VASP package [13, 14]. Projector

Augmented Wave (PAW) pseudo-potentials were used

to present the ionic potentials. The Perdew–Burke–

Ernzerhof (PBE) [15] exchange-correlation functional

was treated at the generalized gradient approximation

(GGA). An energy cut-off 329 eV was found to be

adequate for the calculation of the structural,

electronic,magnetic and elastic properties. The Brillouin

zone integration was performed on a Monkhorst-Pack

[16] 6 × 6 × 6 k-point mesh with a Methfessel–Paxton

[17] smearing of 0.225 eV forRu2Vga and Ru2CrGa.The

elastic constants were predicted using the stress-finite

strain technique.



In table 1, we report our calculated lattice constant (a0),

Bulk modulus (B), the total magnetic moment (M),

elastic constants (Cij), shear modulus (G), ratio of B/G

and Young’s modulus (E) of Ru2VGaandRu2CrGa

alloys. The optimized lattice constants of Ru2VGaand

Ru2CrGa are 6.013 Å, and 5.985 Å, respectively. On the

other hand, the calculated total spin magnetic moments

are 1,15 µB for Ru2CrGa and 0 µB for Ru2VGa. Our

results have beencompared with the available results in

the literature [8-12]. There is a good agreement between

our results and that previously reported. Our estimation

of bulk modulus of 235.70 GPa is smaller than the

calculated value using FPLAPW method (241.40 GPa)

for Ru2VGa [8].

The calculated electronic band structure of Ru2VGa

along the high symmetry directions in the Brillouin zone

given in Fig. 1. It is seen that there is no band gap at the

Fermi level, as a result, Ru2VGa alloy exhibit a metallic

behavior. Our calculated electronic band structure for

Ru2VGa is in good agreement with previous reported

work [8]. From the total and the partial density of states

of Ru2VGa and shown in Fig. 2. The result indicate that

the predominant contributions of the density of states

between -5.9 eV and Fermi level mainly come from the

Ru-4d and V-3d states for Ru2VGa. Similarly, the

contribution of one peak, around 1 eV above the Fermi

level, is dominated by Ru-4d states and V-3d states for

Ru2VGa. Spin-polarized band structures of the Ru2CrGa

alloys for spin-up (majority-spin) and spin-down

(minority-spin) states areshown in Fig. 3

alongthehighsymmetrydirections in theBrillouinzone.

Ru2CrGashowsnearlyhalf-metallicity, becausetheirspin-

down DOS acrosstheFermilevel a little. On the other

hand, the total andthepartialdensity of statesof

Ru2CrGaareshown in Fig. 4.

The lowest valence bands in the energy region that is

lower than -7 eV in both the majority and minority spin

states are mainly due to the ‘‘s’’ electrons of the Ga

atom for Ru2CrGa. The low-energy part around -6 eV in

both the majority and minority spin states are mainly

consisted by Ru-4d states and Cr-3d states for

Ru2CrGa. Similarly, around 1.1 eV above the Fermi

level, in both the majority and minority spin states are

dominated by Ru-4d states and Cr-3d states for

Ru2CrGa.

Elastic constants are significant parameters of a material

and often provide valuable information on the structural

stability. A cubic system has three independent elastic

constants (C11,C12, C44). Mechanical stability of these

compounds has been analyzed in terms of their elastic

constants. For cubic crystals, the conditions for

mechanical stability are given by [19]:

C11 > 0 , C44 > 0 , C11 + 2C12 > 0 , C11 − C12 > 0

The obtained elastic constants for Ru2VGa and Ru2CrGa

satisfy these mechanical stability criterions, indicating

that the Ru2VGa and Ru2CrGa are mechanical stable in

the L21phase.In order to investigate the ductility and

brittleness properties of Ru2VGa and Ru2CrGa, the ratio

of Bulk modulus to shear modulus, B/G, has been

calculated. This ratio can be considered as an empirical

criterion of the extent of the fracture range in the

materials [20]. If the ratio of B/G is higher than1.75,

then the material behaves in a ductile manner. If it is

less than1.75, then that material demonstrates

brittleness. The B/G values are 2.08 and 2.18 for

Ru2VGa and Ru2CrGa, respectively. The B/G values of

Ru2VGa and Ru2CrGa indicate the ductile nature of the

materials. This is in good agreement with the results

found for Ru2VGa [8].


Table 1.Calculated lattice constant (a0), the total magnetic moment (M), elastic constants (Cij), Bulk modulus (B), Shear modulus (G), ratio of B/G and Young’s modulus (E) of Ru2VGaandRu2CrGa alloys.

Compounds References a0 (Å) M (μB)

C11 (GPa)

C12

(GPa) C44

(GPa) B

(GPa) G(GPa) B/G E (GPa)

Ru2VGa

Present 6.013 0 385.76 160.67 113.86 235.70 113.33 2.08 293.03 [8] 6.032 - 388.01 168.10 107.95 241.40 108.75 2.22 283.65

[9, 10] 5.994 - - - - - - - - [11] 5.989 - - - - - - - -

Ru2CrGa Present 5.985 1.15 347.58 162.61 110.36 224.27 102.83 2.18 267.58

[12] 5.991 - - - - - - - -

Figure 1. The electronic band structure for Ru2VGa along the high symmetry directions in the Brillouin zone.

Figure 2. Calculated total and partial density of states for Ru2VGa alloy.

Figure 3. The electronic band structure for Ru2CrGa along the high symmetry directions in the Brillouin zone.

Figure 4. Calculated total and partial density of states for Ru2CrGa alloy.

CONCLUSION

In conclusion, the structural, electronic and elastic

properties of the Ru2VGa and Ru2CrGa Heusler

alloyshave been investigated by DFT. The electronic

and elastic properties of the Ru2CrGaalloy is reported

for the first time in this study. Our calculated

latticeparameters and total magnetic moments are in

good agreement with the theoretical data.


Scientific Research Projects Coordination Unit. Project

Number: FEF.A3.16.002.


REFERENCES

1Heusler, F., Verhandlugen der Deutschen Physikalischen Gesellschaft 1903, 5:219. 2Fuji, S.; Sugimurat, S.; Ishida S.; Asano, S., J. Phys.: Condens. Matter 1990, 2:8583-8589. 3Galanakis, I.;Dederichs, P.H.;Papanikolaou, N., Phys. Rev. B2002, 66. 4Galanakis, I.; Mavropoulas, P.H.; Dederichs, P.H., J. Phys. D: Appl. Phys. 2006, 39. 5Wurmehl, S.;Fecher, G.H.; Kandpal, H.C.; Ksenofontov, V.; Felser, C.; Lin, H.-J.; Morais, J., Phys. Rev. B 2005, 72:184434. 6Kübler, J.; Fecher, G.H.; Felser, C. Phys. Rev. B 2007, 76:024414. 7Arıkan, N.; İyigör, A.; Candan, A.; Uğur, Ş.; Charifi, Z.;

Baaziz, H. and Uğur, G. Journal of Materials Science 2014, 49:4180-4190. 8Abbassa, H.; Hadjri-Mebarki, S.; Amrani, B.; Belaroussi, T.; Khodja K.D. and Aubert, P., Journal of Alloys and Compounds 2015, 637:557-563.

9Mondal, S.; Mazumdar C. and Ranganathan, R., In American Institute of Physics Conference Series 2013, 1536:825-826. 10Mondal, S.; Mazumdar C. and Ranganathan, R., In American Institute of Physics Conference Series 2013, 1512:978-979. 11Yin, M.; Nash, P., Journal of Alloys and Compounds 2015, 634:70-74. 12http://oqmd.org/materials/entry/502937. 13Kresse, G. and Hafner, J., Phys. Rev. B 1993, 47:558. 14Kresse, G. and Furthmuller, J., Phys. Rev. B 1993, 54:1169. 15Perdew, J. P.; Burke K. and Ernzerhof, M., Phys. Rev. Lett. 1996, 77:3865. 16Monkhorst, H. J. and Pack, J. D., Phys. Rev. B, 1976, 13:5188. 17Methfessel, M.; Paxton, A.T., Phys. Rev. B 1989, 40:3616. 18Page, Y. L. and Saxe, P., Phys. Rev. B 2002, 65:104104. 19Born, M. and Huang, K., in Dynamical Theory of Crystal Lattices 1954. 20Pugh, S.F., Philos. Mag. 1954, 45:823.


Determination of The Time-Independent Rheological Behavior of

Peanut Butter and Its Modeling

Hakan YOĞURTÇU*

Department of Chemical Engineering,Faculty of Engineering, Munzur University, TR-62000 Tunceli, Turkey

*[email protected]

Peanut, also known as groundnut (Arachishypogaea L.), is a popular cookies in Turkey. On the other hand, the peanut butter from ground and roasted the peanut is a semi-solid paste and a significant source of protein, dietary fiber, vitamin E and B6, and dietary minerals as phosphorus, magnesium, zinc. In this study, the rheological behavior of a peanut butter sample was investigated by using rotational rheometer at different shear rate and five different temperatures (10, 20, 30, 40, 50 °C). It was observed that the peanut butter is non-Newtonian pseudo plastic fluid. Power-Law, Casson and Bingham models were used to describe the time-independent flow behavior of the peanut butter. The determination of coefficient (R2), root mean square error (RMSE), chi-square (2) and mean absolute percentage error (MA%E) values that show compatibility to these models were determined. The determination coefficient values were found to vary an interval of 0.907-0.999. An Arrhenius relationship was used to determine the effect of temperature on apparent viscosity of the peanut butter. The activation energy (Ea) values were calculated at different shear rates. It was observed that the activation energies vary from 46818.63-51952.52 J/mol.

Keywords: peanut butter, food rheology, modeling

INTRODUCTION

Peanut, also known as groundnut (Arachishypogaea L.), is a popular cookies in Turkey and has global importance.It is widely grown in the tropics and subtropics, being important to both smallholder and large commercial producers. Peanut butter is produced from peanut kernels by roasting, grinding and mixing processes. This food product from ground and roasted the peanut is a significant source of protein, dietary fiber, vitamin E and B6, and dietary minerals as phosphorus, magnesium, zinc. Emulsifiers are added to ensure that the oil released by grinding remains in suspension. Peanut butter has been described as paste-like dispersion where non-colloidal small solid spherical peanut particles are dispersed in an oil phase [ 1,2]. The total lipid content of peanut butter is 47-50 % [3] and because of the approximate 50/50 solid particle/lipid composition of peanut butter, it is a semi-solid food material. Rheology science analyses the deformation and flow of substances under the applied forces (external forces and internal forces). In particular, it concerns to deformation behavior of fluid materials such as liquids, gels, emulsions, solutions etc. Food is any substance containing the components, such as carbohydrates, fats, protein, vitamin and minerals, necessary for human nutrition. Food includes a wide range of biological

materials with diverse rheological character [4]. Foods, however, are complex materials structurally and , in many case, they consist of mixtures of solid as well as fluid structural components [5]. A knowledge of the rheological properties of various food materials is important in (i) the design of flow processes for quality control, (ii) storage and stability, (iii) designing texture, (iv) nutritive characteristic. Science rheology is the study of the deformation of matter, the terms of strain, stress and shear should be well known. Strain is the deformation in term of relative displacement of the particles composing the matter. Stress defined as a force per unit area is the measure of internal forces acting within the deforming matter. Shear is the deformation of the matter in one direction only. There is a number of published works about the squezing viscometry [6, 7], effect of stabilizer on texture and viscosity [8] and rheological properties [9]of peanut butter in literature. Campanella and Peleg [6] investigated the viscous behaviour of peanut butter and determined the power law parameters by using squezing flow test. Citerne et al. [9] studied the rheological properties of two types of commercial peanut butter by using stress controlled rheometer. They determined the Bingham and Casson yield stresses and time dependent elastic and loss moduli. However, there is no study about the time-independent rheological behavior of peanut butter and its modeling at different temperatures. Therefore, the aim of this


study is to determine the time-independent rheological behaviour of peanut butter as a function of temperature and its modeling.

MATERIAL AND METHODS Material Peanut butter used in this study was obtained from a factory in Turkey. The peanut butter containing 81 % peanut kernel homogenized by mixing and kept in a refrigerator. The composition of peanut butter sample is shown in Table 1. Table 1. The composition of peanut butter sample used. Parameter Value (in 100 g) Energy (kJ) 2460 Total fat (g) 42.7 Saturated fatty acids (g) 9.5 Total carbohydrates (g) 31.0 Sugar (g) 20.4 Dietary fiber (g) 4.4 Protein (g) 22 Sodium (g) 0.29 Potassium (g) 0.70 Soluble solid material (°Brix) 72

Methods

Rheological Test Rheological measurements of peanut butter were carried out using a rotational Brookfield Rheometer (RV DV3T Extra, Brookfield Engineering Laboratories, Inc. USA) equipped with SC4-29 spindle and SSA (Small Sample Adapter). The viscosity measurements were made at different shear rates (0-1 s-1) and temperature range between10-50 °C. Desired temperatures were provided and maintained using a thermostatic circulating bath coupled to the SSA with an accuracy of ± 0.1 °C. All the experiments were replicated. Modeling Different rheological models shown in Table 2 were used to represent the time-independent rheological behavior of the peanut butter.

Table 2. Rheological models used. Model Name Equation Power Law 𝜏 = 𝑘𝛾 𝑛 Bingham 𝜏 − 𝜏𝑜 = 𝜇′𝛾 Casson 𝜏0.5 = 𝑘𝑜𝑐 + 𝑘𝑐 𝛾

0.5 The temperature dependence of viscosity was described using the following Arrhenius equation [10].

𝑎=

∞∙ 𝑒𝑥𝑝

𝐸𝑎

𝑅 ∙ 𝑇

The consistency between the experimental data and mathematical model was determined by using statistical parameters, i.e. determination of coefficient (r2), mean absolute percentage error (MA%E), chi-square (2) and root mean square error (RMSE)[11].

MA%E = 100

N

X𝑒𝑥𝑝 , i -X𝑝𝑟𝑒 , i

X𝑒𝑥𝑝 , i

Ni=1

2 = (𝑋𝑒𝑥𝑝 , i-X𝑝𝑟𝑒 , i)

2Ni=1

N-z

RMSE = (X𝑒𝑥𝑝 , i-X𝑝𝑟𝑒 , i)

2Ni=1

𝑁


Time-Independent Rheological Behavior Fig. 1 and Fig. 2 show the flow curves of peanut butter at different temperatures for shear stress and apparent viscosity versus shear rate, respectively. From Fig. 1, it can be seen that the shear stress-shear rate relationship is non-linear. Therefore rheological behavior of peanut butter is non-Newtonian. The decreasing of viscosity with increasing of shear rate shows that the peanut butter is peseudoplastic type fluid, Fig. 2.Because the peanut butter has high soluble solid matter, its viscosity values is high. Arslan et al. [12] expressed that the viscosity of tahin-pekmez blends increase with an increase in tahin concentration of blends.

Figure 1.Shear stress-shear rate relationship of peanut butter at different temperatures.

0

50

100

150

200

250

300

0 0.25 0.5 0.75 1 1.25

Shea

r Str

ess

(Pa)

Shear Rate (s-1)

10 C

20 C

30 C

40 C

50 C


Figure 2. Change of viscosities of peanut butter with shear rate at different temperatures. Evaluation of Mathematical Models The experimental data were applied to mathematical models in Table 2. It was determined the model constants at different temperatures seen in Table 3. From the Power Law model, the values of flow behavior index, n, at all temperatures considered were found to be less than unity, n < 1. Therefore, it can be said that the peanut butter exhibit the pseudoplastic fluid behavior. Consistency indices, k, decreased with increasing the temperature.

Table 3.Constants belong to rheological models.

Model

Constants Temperature (°C)

10 20 30 40 50 Power Law n 0.76 0.77 0.78 0.79 0.58

k 328 215 123 62 20 Casson kc 16.2 13.3 9.99 7.01 3.03

koc 2.46 1.82 1.37 0.99 1.40 Bingham ı 327 215 120 58 18

o 28.04 16.11 9.53 5.25 2.33

Table 4.Values of statistical parameters for rheological models.

Temperature (°C) Model Statistical

Parameter 10 20 30 40 50

Pow

er

Law

r2 0.997 0.993 0.989 0.991 0.965

MA%E 2.86 4.89 5.61 5.52 10.26

2 20.617 28.433 8.376 3.071 2.977

RMSE 4.295 4.769 2.662 1.612 1.522

Cas

son

r2 0.996 0.999 0.995 0.991 0.907

MA%E 2.71 2.14 4.47 5.96 17.71

2 37.205 2.687 9.914 5.314 3.661

RMSE 5.770 1.466 2.896 2.120 1.687

Bin

gham

r2 0.990 0.998 0.991 0.982 0.747

MA%E 5.12 3.22 5.83 9.96 21.54

2 56.739 7.889 13.613 6.640 7.552

RMSE 7.332 2.665 3.545 2.476 2.591

Also, similar changes can be expressed for Casson model constant, kc, and Bingham viscosity, ı. The results of statistical evaluation, which is an indicator of the compatibility between experimental results and the models used, are seen in Table 4.The best model describing the rheological behavior of peanut butter waschosen as the one with the highest determination coefficient (r2), the least chi-square (2), least root mean square error (RMSE), and least percentage error (E%). While the Power Law model is a more suitable model at temperatures of 10, 40 and 50 °C, it is seen that Casson model has a more capability in representation of the experimental data at temperatures of 20 and 30 °C. Effect of Temperature The change of the apparent viscosities of the peanut butter with temperature is seen in Fig. 3. It was seen that the apparent viscosities of peanut butter decreased with an increase in the temperature at all of shear rates (0.1, 0.4 and 0.75 s-1).The values of parametersof Arrhenius equation (infinite viscosity,, and activation energy, Ea) and the results of statistical evaluation are seen in Table 5.It is seen that the values of infinite viscosity decreased while the activation energy increased with an increase in the shear rate. The values of activation energy that is an indicator of temperature dependence of peanut butter were determined as 46818.63, 47720.70 and 51952.52 J/mol at shear rate of 0.1, 0.4 and 0.75 s-1, respectively. Therefore, it can be said that the apparent viscosities of peanut butter are more affected by the temperature with an increase in the shear rate. However, Table 5 shows that the confidence of Arrhenius equation decreases with increasing of shear rate.

Figure 3.Change of the apparent viscosity with temperature at different shear rates, : 0.1 s-1, O: 0.4 s-1, : 0.75 s-1.

0

100

200

300

400

500

600

700

800

0 0.25 0.5 0.75 1 1.25

Appare

nt Viscosity (Pa · s)

Shear Rate (s-1)

10 C

20 C

30 C

40 C

50 C

0

100

200

300

400

500

600

700

10 20 30 40 50

Appare

nt Viscosity (Pa · s)

Temperature ( C)


Table 5.Arrhenius constants and statistical parameters.

(s-1) x 107

(Pa s) Ea

(J/mol) r2 MA%E 2 RMSE

0.1 14.7 46818.63 0.990 8.21 1898.76 33.75 0.4 7.78 47720.70 0.973 14.25 1954.86 34.25

0.75 1.16 51952.52 0.927 26.77 4428.53 51.55

NOMENCLATURE

Shear rate (s-1) 2 Khi-square a Apparent viscosity (Pa s) Infinite viscosity (Pa s) Shear stress (Pa) o Yield stress (Pa) ı Bingham viscosity (Pa s) Ea Activation energy (J/mol) k Consistency index (Pa sn) kc Square root of consistency index (Pa0.5 s0.5) koc Square root of yield stress (Pa0.5) MA%E Mean absolute percentage error n Fluid behavior index (dimensionless) N Number of observations R Gas constant (8.314 J/mol K) r2 Determination coefficient RMSE Root mean square error T Absolute temperature (K) Xexp Experimental data Xpre Predicted data z Number of constants in model

CONCLUSION

In this study, rheological behavior of peanut butter was investigated by rotational rheometer at different temperatures. Peanut butter that is a semi-solid food material behaves as non-Newtonian pseudoplastic fluid. The non-Newtonian rheological data were described several models. Power Law and Casson models among the models used are suitable models represent the experimental data. Apparent viscosity of peanut butter decreased with increasing the temperature as expected. The effect of temperature on viscosity of peanut butter was described by the Arrhenius equation and the

activation energy increased with increasing the shear rate.

REFERENCES

1 Co, E.; Marangoni, A.G. J. American Oil Chem. Soc. 2012, 89(5), 749-780. 2Carreau, P.J.; Cotton, F.; Citerne, G.P.; Moan, M. (2002) Engineering and food for the 21st century, 327-345.In Rheological properties of concentrated suspensions: applications in foodstuffs. (Eds. J. Welti-Chanes, G. Barbosa-Canovas, J.M. Aguilera), CRC Press, New York. 3Suchoszek-Lukaniuk, K.; Jaromin, A.; Korycinska, M.; Kozubek, A. (2011). Health benefits of peanut (Arachishypogaea L.) seeds and peanut oil consumption, (873-880). In Nuts and seeds in health and disease prevention (Eds. V.R. Preedy, R.R. Watson, V.B. Patel). Elsevier, London. 4Stading, M. (2009) Food Rheology, 283-306: In Rheology Vol. II (Eds. CrispuloGallegosay), Encyclopedia of Life Support Systems (EOLSS). 5Tabilo-Munizaga, G.; Barbosa-Canovas, G. V. J. Food Eng. 2005, 67, 147-156. 6Campanella, O.H.; Peleg, M. J. Food Sci. 1987, 52, 180-184. 7Totlani, V.M.; Chinnan, M.S. Peanut Sci. 2007, 34(1), 1-9. 8Sun, A.; Gunasekaran, S. J. Texture Stud. 2009, 40, 275-287. 9Citerne, G.P.; Carreau, P.J.; Moan, M. RheolActa.2001, 40, 89-96. 10Saravacos, G.D. J. Food Sci. 1970, 35, 122-125. 11Yoğurtçu, H. J. Agr. Sci. 2016, 22, 237-248. 12Arslan, E.; Yener, M.E.; Esin, A. J. Food Eng. 2005, 69, 167-172.


Stability and Durability of Polyvinyl Chloride Membranes Consisting

of Aliquat 336

Yasemin YILDIZa, Aynur MANZAKb

aVocational School of Health Services, Department of Medical Services and Techniques, Sakarya University,TR-54100,

Sakarya,Turkey bDepartment of Chemistry, Faculty of Art and Science, Sakarya University, TR-54187, Sakarya, Turkey


Keywords:type contact angle, polymeric membrane, characterization

INTRODUCTION

Industry generates a great variety of

contaminants containing heavy metals. Already many water resources and lands contaminated by pollutants in the world. This pollutions increase relevance metal extraction. So studies concentrate on the importance of metal extraction in wastewater treatment in recent years. This increase has provided the development of a new type of liquid membranes, commonly called polymeric inclusion membranes.

Polymeric inclusion membranes (PIMs) are

preferred to others membranes because of chemical resistance, ease of application and better mechanical property. PIMs occur from polymer, that contains solvent, extractant and plasticizer. Polymer material provides durability of membrane [1]. Extractant is used to complexing agent or an ion-exchanger. Plasticizer conduces to mix polymer with extractant and it brings flexibility [2]. This ends up with a thin film that removes polluter from solution. It is also an important item to analyse the surface characterization of PIMs because membrane morphology guarantees required separation performance [3].

Membrane morphology impresses metal

extraction that it is substantial parameter in the membrane performance [4]. There are a number of methods to determine the membrane morphology; some of these methods are electron microscopy (SEM), atomic force microscopy (AFM) and ATR technique. Besides, contact angle is used to determine the membrane morphology.

Membrane stability and durability are also fundamental items for transport. Extractant

hydrophobicity and solubility specify membrane stability [5]. Contact angle measuring helps the determination of surface properties, hydrophilic and the hydrophobic characteristics of a polymer membrane. Hydrophilicity of the membrane has an important influence on its performances. Low contact angle demonstrates high water affinity. Fouling formation generates change in the contact angle because differences in the surface properties of deposit [6].

This study was focused on membrane stability, durability and characterization as well as metal extraction. In this study were carried out to extract for Co (II) from dilute aqueous solution including cobalt and nickel via polymeric inclusion membranes (PIMs) consisting of Aliquat 336. Membrane surface roughness was examined with a digital microscope (Huvitz 5800). In order to determine membrane morphology electron microscopy (SEM), atomic force microscopy (AFM), and measure of contact angle with dropping technique were used.

The PVC and 2-nitro phenyl pentyl ether (2-

NPPE) of analytical grade were purchased from Fluka; tetrahydrofuran from Riedel-de Haen tributyl phosphate, cobalt (II) chloride hexahydrate, nickel (II) chloride hexahydrate, acetic acid, sodium hydroxide, ammonium, triethanolamine, ammonium thiocyanate and trioctyl methyl ammonium chloride from Merck were used in the present study.

PIM membranes were prepared according to

casting solution. First, 2-NPPE (0.2 mL) was added to 70 mL of tetrahydrofuran, where PVC (480 mg) was

dissolved at room temperature. Aliquat 336 and TBP were added, after the solution was mixed, which was


followed by 2 h of mixing to obtain a uniform solution. To slow down evaporation, the solvent of mixed solution, a glass square container (24 cm × 24 cm) was used and kept at room temperature overnight. Then, a few drops of cold water (at room temperature) were placed and mixed on the top of the polymer film twice for experiment, [1] which resulted in the formation of a membrane. The membrane was removed from the container and had an average thickness of 25 μm,

according to a digital micrometer (Salu Tron Combi-D3).

This membrane, which is known as the

polymeric film, was placed between two glass cells. A two-compartment permeation cell made of Pyrex glass using flat-sheet membranes of 12,56 cm2 area (A) was used to study transport process of metal ions from the aqueous solutions through the PIM. Equal volumes (250 mL) of the feed and strip phase were used in permeation cell. The cobalt and nickel salts were dissolved in distilled water to create the stock solutions for cobalt and nickel. To select cobalt ions from the mixture against to nickel, the feed mixture was mixed with ammonium thiocyanate (NH4SCN). 1 M acetic acid/1 M sodium acetate buffer was used to adjust the pH of the feed solution. For the stripping phase, 1 M NH3 + 1 M TEA were selected to make the stripping solution. During the PIM transport experiment, metal concentration was determined using an atomic absorption spectrometer (Shimadzu AA6701F).


SEM (Fig. 1), AFM (Fig. 2) and contact angle (Fig. 3) were used to characterize the membrane. Fig. 1 illustrates the SEM image of PIM formed by PVC + 2-NPPE + TBP + Aliquat 336. Fig. 2 shows the AFM image of PIM formed by PVC + 2-NPPE + TBP + Aliquat 336. The morphology of membrane has a rough surface nature. As put it, [7-8] these surface areas may be account for different solvent vaporization rates or pores within the membranes that were filled by 2-NPPE + Aliquat 336 + TBP [9-10]. The results of SEM and AFM studies are in compliance with each other.

Usually, PIMs are spilled on the surface of the glass, so we hope that morphology of membrane on the glass side will be quite different from the morphology of the membrane exposed to the air [4]. This result is obtained from AFM images of membrane. Fig.2a and Fig.2b shows both surfaces different. It thinks that this difference is associated with difference extraction properties in both of surface. Hydrophobic character of the PVC membrane was determined with contact angle measurements. It seems that fresh membrane is hydrophobic character but

waited membrane is hydrophilic character due to the decline of the contact angle. Contact angle of used membrane could not be measured because surface of the membrane is not smooth. Fig. 3 is the contact angle of waited and fresh polymeric membrane. The result showed that membrane has hydrophobic characteristic because contact angle is above 90°. The value of average contact angle is 37° for used membrane. Fig.4-5-6 are the digital microscope images of three types of membranes of which were waited, fresh, and used polymeric membrane. For a comparison, the image of digital microscope were equal to homogeneous surface and small particular size, roughness surface and large particular size, filled with metals of particular for waited, fresh and used membranes. This digital microscope images were compared with each other. The results showed that membrane surface has different surface roughness because it is affected from waiting time before experiment. Increased waiting time before experiment influence membrane of particle size and extraction efficiency. After the fifth repetition, as shown in Figure 7, a rapid decline in the value of RF was observed. However, after the eighth repetition in the studies, it was observed that the value of RF remains almost constant. It is speculated that this situation stems from leaving Aliquat 336, which was used as a carrier in the polymeric membrane. This situation depends on vastness of the dispersion coefficient between organic /water phase. Diffusion coefficient decrease means more carrier depart from organic phase, by the way this issue decreases the membrane stability [11-12]. Fig. 8 shows analysis of cobalt ions measured by Atomic Absorption Spectrophotometer. Extraction efficiency of cobalt ions was obtained as 60 % in feed phase after 7 hours. This is confirmed that using as a carrier Aliquat 336 is selective for cobalt. Nickel was not transported. The durability of membrane used in the study was two weeks. There is not a rupture and puncture of the membranes at the end of time. But, it is determined that cobalt ions of RF value stable after two weeks.


Figure 1. Sem image of polymeric membrane

Figure 2a. AFM image of polymeric membrane-to-air side.

Figure 2b. AFM image of polymeric membrane-to-glass side

Figure 3. Contact angle of waited and fresh polymeric membrane

Figure 4. Dijital microscope images of waited membrane.

Figure 5. Dijital microscope images of fresh membrane.


Figure 6. Dijital microscope images of used membrane.

0

20

40

60

80

100

1 2 3 4 5 6 7 8 9 10

RF

The number of repetitions

Figure 7. The number of repetitions

Figure 8. Extraction efficiency of cobalt ions in feed phase

CONCLUSION

Polymer inclusion membrane was prepared using PVC, Aliquat 336, TBP and 2-NPPE. SEM, AFM and contact angle were used for characterization. Effect of the membrane lifetime on the recovery factor was investigated in the acidic mixture of cobalt and nickel solutions. As a result, after the seventh repetition, it has been identified that the RF is reduced.

ACKNOWLEDGEMENTS

We are grateful to Worcester Polytechnic Institute in MA USA and Sakarya University Department of Metallurgical and Materials Engineering for measurement of polymeric membrane samples.

REFERENCES

1Saf, A.,Ö.; Alpaydin, S.; Coskun, A.; Ersoz, M. J. Membr. Sci. 2011, 377, 241– 248. 2Gajda, B.; Bogacki, M.B. J. Ach. Mat. And Manf. Eng. 2012, 55, 673–678. 3Khulbe, KC.; Feng, CY.; Matsuura, T. Water and Wastewater Treat. Tech. 2008. 4Wang, L.; Paimin, R.; Cattrall, R.W.; Wei, S.; Kolev, S.D. J. Membr. Sci. 2000, 176 (1),105–111. 5Argiropoulos, G.; Cattrall, R.W.; Hamilton, I.C.; Kolev, S.D.; Paimin, R., J. Membr. Sci. 1998, 138 (2), 279–285. 6Kertész, Sz., Freitas, T. B.; Hodúr, C.; Analecta. 8, 18–22. 7Kozlowski, C.A.; Walkowiak, W. J. Membr. Sci. 2005, 266(1-2), 143-150. 8Tor, A.; Arslan, G.; Muslu, H.; Celiktas, A.; Cengeloglu, Y.; Ersoz, M. J.Membr. Sci., 2009, 329(1-2), 169-174. 9Ulewicz, M.; Lesinska, U.; Bochenska, M. Physicochem. Probl. Miner. Process., 2010, 44, 245-256. 10Kebiche-Senhadji, O.; Mansouri, L.; Tingry, S.; Seta, P.; Benamor, M. J. Membr. Sci., 2008, 310(1-2), 438-445. 11Levitskaia, T.G.; Lamb, J.D.; Fox, K.L.; Moyer, B.A. Radiochimica Acta, 2002, 90 (1), 43–52. 12Aguilar, J.C.; Miguel, E.R.d.S.; Gyves, J.D.; Bartsch, R.A.; Kim, M. Talanta, 2001, 54 (6), 1195–1204.


Optimization of Digestion Procedures for the Determination of Lead

and Cadmium in Mussel Samples

Mustafa TÜZEN

Gaziosmanpasa University, Faculty of Science and Arts, Chemistry Department, 60250 Tokat, Turkey E-mail: [email protected]

Keywords:Digestion, mussel, lead, cadmium, microwave digestion, graphite furnace atomic absorption spectrometry

INTRODUCTION

Mussels have been widely used a bioindicator for the

determination of heavy metal pollution in the sea1-3.

They are accumulated the heavy metals in their tissue at

high ratio. Previous studies have been carried out to

assess the contamination of aquatic species by some

heavy metal ions4,5. Seafood which are containing high

amount heavy metals and pollutants may pose a risk to

consumers. Lead and cadmium are known toxic element

at relatively low doses. The presence of heavy metals in

seafood and mussel depends on several factors such as

geographic location, species and size, metal

concentrations in the sea water, solubility, temperature,

salinity, pH, etc.6.

Wet and dry ashing procedures are slow and time

consuming. Microwave digestion method is simple, fast,

good accuracy and precision for the determination of

traces heavy metal ions in food samples7,8.Various

instrumental techniques such as flame atomic absorption

spectrometry (FAAS), graphite furnace atomic

absorption spectrometry (GFAAS), inductively couple

plasma optic emission spectrometry (ICP-OES),

inductively couple plasma mass spectrometry (ICP-MS)

are widely used for the determination of heavy metals in

mussel samples1-5. GFAAS has some advantages for the

detection of heavy metal ions with respect to its easy

usage, low cost and sensitivity.

In this study, lead and cadmium ions were

determined in mussel samples by using GFAAS after

microwave digestion method. Various parameters such

as volume of acids, temperature, pressure and power of

microwave were optimized.

MATERIAL AND METHODS

Sampling

Mussel samples were collected from random

commercial catches from Black Sea, Turkey. The

samples were washed with distilled deionized water and

dried in an oven (60 °C; 48 h) to a constant dry weight.

Then, they were ground to produce homogeneity.

Reagents

All reagents were of analytical reagent grade. Double

distilled deionised water (Milli-Q Millipore 18.2

MΩcm-1 resistivity) was used for all dilutions. HNO3,

H2O2, and HCI were of analytical reagent quality (E.

Merck, Darmstadt, Germany). Lead and cadmium

standard solutions (1000 mg/L) were purchased from

(Sigma Chem. Co. St. Louis, USA).

Apparatus

Perkin Elmer AAnalyst 700 model (Norwalk,

CT, USA) atomic absorption spectrometer equipped

with HGA graphite furnace and with deuterium

background corrector was used. Lead and cadmium

were determined in graphite furnace. Argon was used as


inert gas. Pyrolytic-coated graphite tubes with a

platform were used. Samples were injected into the

graphite furnace using Perkin Elmer AS-800

autosampler. The operating parameters for lead and

cadmium were given in Table 1. 200 µg NH 4H2PO4 for

lead and 15 µg Pd+10 µg Mg(NO 3)2 for cadmium were

used as matrix modifiers. Milestone Ethos D microwave

(Sorisole-Bg Italy) closed system (maximum pressure

1450 psi, maximum temperature 300 ºC) was used for

the digestion of samples.

Table 1. Instrumental analytical conditions of lead and

cadmium in GFAAS

Instrumental

Instrumental

conditions conditions

Pb Cd

Wavelength (nm) Wavelength (nm) 283.3 326.1

Slit width (nm) Slit width (nm) 0.7 0.2

Argon flow rate (mL/min) 250 250

Sample volume (µL) 20 20

Modifier (µL) 5 10

Heating program temperature

Drying 1 100 (5, 20) a 100 (5, 20)

Drying 2 140 (15, 15) 140 (15, 15)

Ashing 900 (10, 20) 950 (10, 20)

Atomization 1900 (0, 5) 1800 (0, 5)

Cleaning 2600 (1, 3) 2600 (1, 3) a ºC (ramp time (s), hold time (s)

Microwave Digestion

0.25 g certified reference materials (NRCC-DORM-

2 Dogfish Muscle) and 0.5 g of mussel samples were

digested with 6 mL of concentrated HNO3 (65 %) and 2

mL of concentrated H2O2 (30 %) in microwave

digestion system and diluted to 10 mL with double

deionized water. Digestion conditions of the microwave

system for the samples were applied as 2 min for 250

W, 2 min for 0 W, 6 min for 250 W, 5 min for 400 W, 8

min for 550 W, vent: 8 min, respectively. A blank digest

was carried out in the same way. Various parameters

such as volume of acids, temperature, pressure and

power of microwave were optimized before digestion

procedure.


Detection limit is defined as the concentration

corresponding to three times the standard deviation of

ten blanks. Detection limit values of Pb and Cd in

GFAAS were found to be 0.18 µg/L and 0.10 µg/L,

respectively.The relative standard deviations were found

6 %. t-test was used in this study (p<0.05). The

accuracy of the method was confirmed with analyzing

of standard references material (NRCC-DORM-2

Dogfish Muscle). The results are given in Table 2. The

achieved results were in good agreement with certified

values for analytes. The recovery values for lead and

cadmium were found quantitative for microwave

digestion method. The mixture of 6 mL of concentrated

HNO3 and 2 mL of concentrated H2O2 was found

enough for the digestion of certified reference material

and mussel samples.

Table 2. Observed and certified values (µg/g) of lead and

cadmium in NRCC-DORM-2 Dogfish Muscle as average ±

S.D.

Element Certified

value

Observed

value

Recovery

(%)

Pb 0.065 0.063±0.003 97

Cd 0.043 0.041±0.002 95

Totally 10 mussel samples were analyzed in this

study. Lead and cadmium concentrations were

determined on a dry weight basis.Lead concentration in

analyzed mussel samples was found in the range of

0.50-2.80 µg g -1. Cadmium levels in analyzed mussel

samples were found in the range of 0.95-3.20 µg g -1.

The comparison of lead and cadmium levels in analyzed

mussel samples with literature values are given in Table

3. The maximum lead and cadmium level permitted for


sea foods containing shell is 0.5 mg kg-1 according to

Turkish Food Codex9. Lead and cadmium levels in

analyzed mussel samples were found to be higher than

legal limits and European Commission limits. The

European Commission is given permissible level

forconsumption of lead and cadmium in foodstuff as 1.5

µg g -1 and 1.0 µg g -1, respectively in wet weight10.

Table 3. Comparison of lead and cadmium levels in mussel

samples with literature values

Literature values Pb (µg/g) Cd (µg/g)

Eastern Black Sea3 5-21 2-4

Morocco11 1-26 2-35

Spanich12 1-3 <1–1.4

Turkish coastline1 0.06-22.9 0.09–3.32

Adriaticcoastal area5 1.90–8.91 0.90–2.69

Adriatic Sea13 1.39–5.69 0.27–0.77

Goro Bay, Italy, North

Adriatic Sea14

15.8–29.0 3.7–4.3

This study 0.50-2.80 0.95-3.20

CONCLUSION

A simple and reliable determination of lead and cadmium in mussel samples by using GFAAS was performed in this study. The accuracy of the microwave digestion method was verified by using certified reference material and quantitative recovery values were obtained. Mussel samples should be analyzed more often in Turkey with respect to toxic elementssuch as lead, cadmium, mercury, etc. This study is contained useful information for the understand of high levels of toxic heavy metals in mussel to consumers.

ACKNOWLEDGEMENTS

The author would like to thanks to Gaziosmanpasa University and Turkish Academy of Sciences for financial support.

REFERENCES 1Belivermis, M.: Kılıc, O.: Cotuk, Y. Chemosphere,2016, 144, 1980-

1987. 2Topcuoglu, S.: Kırbasoglu, C.:Güngör, N. Environ. Int.2002, 27, 521-

526. 3Cevik, U.: Damla, N.: Kobya, A.I.: Bulut, V.N.: Duran, C.:Dalgıc,

G.: Bozacı, R. J. Hazard. Mater.2008,160, 396-401. 4Alas, A.: Ozcan, M.M.: Harmankaya, M. Environ. Monit.

Assess.2014, 186, 889-894. 5Jovic, M.:Stankovic, S. FoodChem. Toxicol. 2014, 70, 241-251. 6Stankovic, S.:Jovic, M.: Stankovic, A.R.: Katsikas, I. Heavy metals

in seafood mussels. Risks for human health. In: Lichtfouse, E.:

Schwarzbauer, J.: Robert, D. (Eds.), Environmental Chemistry for a

Sustainable World, Vol. 1: Nanotechnology and Health Risk, Part II,

Chapter 9. Springer, Netherlands, 2012, 311-373. 7Tuzen, M. FoodChem. Toxicol. 2009, 47, 1785-1790. 8Mendil, D.: Demirci, Z.: Tuzen, M.: Soylak, M. FoodChem.Toxicol.

2010, 48, 865-870. 9Anonymous, Regulation of setting maximum levels for certain

contaminants in foodstuffs. Official Gazette, May 17, 2008, Iss:

26879. 10European Commission, Commission Regulation (EC) No.

1881/2006 of setting maximum levels for certain contaminants in

foodstuffs. Off. J. Eur. Union L, 2006, 364(5), 1–34. 11Maanan, M. Morocco, Environ. Toxicol. 2007, 22, 525-531. 12Besada, V.:Fumega, J.: Vaamonde, A. Sci. Total Environ. 2002, 288,

239-253. 13Çullaj, A..Lazo, P.: Duka, S. Heavymetalsandmetallothioneinlevels

in musselsamples of Albanianseacoast. MAP Technical Reports Series

No. 166, UNEP/MAP, Athens 01/2006; Series No. 166. 14Locatelli, C. J. Phys. 2003, 107, 785-788.


Atomic Absorption Spectrometric Determination of Some Heavy

Metal Ions in Boiled Grape Juice Samples

Mustafa TÜZEN

Gaziosmanpasa University, Faculty of Science and Arts, Chemistry Department, 60250 Tokat, Turkey E-mail: [email protected]

Keywords:Heavy metals, boiled grape juice, microwave digestion, flame atomic absorption spectrometry

INTRODUCTION

Determination of heavy metals in boiled grape juice

samples is very important for human health. Some

heavy metal ions such as iron, copper, zinc and

manganese are known as essential element for our life.

Lead and cadmium is also known as toxic heavy metal

even at trace levels. When essential elements are taken

high levels, they can produce toxic effects1. Iron,

copper, zinc and manganese may be found in foods

either depending on cultivationplace and property of

plants naturally or by contaminationduring industrial

processes such as preservation and cooking2.

Wet and dry ashing procedures are slow and time

consuming and analyte losses in ashing process are

problem.Microwave digestion in the closed system are

reduced chemical use and considerably reduced

potential hazards as well as costs3. Inductively couple

plasma optic emission spectrometry (ICP-OES) and

inductively couple plasma mass spectrometry (ICP-MS)

are used for the determination of heavy metal ions in

food samples4, but they are very expensive and complex

techniques. Flame atomic absorption spectrometry is

widely used technique for the determination of toxic and

essential elements in food samples due to its cheap,

sensitive and easy usage5.

In this study, iron, zinc, manganese and copper were

determined in boiled grape juice (pekmez) samples from

Tokat, Turkey by flame atomic absorption spectrometry

(FAAS) after microwave digestion method.

MATERIAL AND METHODS

Boiled grape juice samples (pekmez) were collected

from Tokat city, Turkey. NIST SRM 1515 Apple

Leaves (0.25 g) and pekmez samples (1.0 g) were

digested with 6 mL of concentrated HNO3 (65 %) and 2

mL of concentrated H2O2 (30 %) in Milestone Ethos D

model closed vessel microwave digestion system

(maximum pressure 1450 psi, maximum temperature

300 °C) and diluted to 10 mL with double deionized

water. Digestion conditions of the microwave system

for the samples were applied as 2 min for 250 W, 2 min

for 0 W, 6 min for 250 W, 5 min for 400 W, 8 min for

550 W, vent: 8 min, respectively. A blank digest was

carried out in the same way.

Perkin Elmer AAnalyst 700 model (Norwalk, CT, USA)

flame atomic absorption spectrometer (FAAS) was used

in the experiments. For flame measurements, a10 cm

long slot-burner head, a lamp and an air-acetylene flame

were used. Working conditions of elements in FAAS

are given in Table 1. The element standard solutions

used for calibration were prepared by diluting stock

solutions of 1000 mg L-1 of each element supplied from

Sigma (Sigma Chem. Co. St. Louis, USA). Standard

reference material (NIST-SRM 1515 Apple leaves) was

used for quality test.


Table 1. Instrumental analytical conditions of investigated elements in FAAS Element Acetylene

(L/min)

Air

(L/min)

Wavelength

(nm)

Slit

width

(nm)

Fe 2.0 17.0 248.3 0.2

Cu 2.0 17.0 324.8 0.7

Zn 2.0 17.0 213.9 0.7

Mn 2.0 17.0 279.5 0.2


The recovery values were found quantitative for

microwave digestion method. The relative standard

deviations were less than 7% for all investigated

elements. T-test was used to determine significant

differences between mean values (p<0.05). The

accuracy of the method was performed by means of

trace element determination in standard reference

material (NIST-SRM 1515 Apple leaves). The results

are given in Table 2. The observed results were in good

agreement with certified values. According to IUPAC

definition, instrumental detection limit (LODi) of the

flame AAS based on three times the standard deviations

of the blank (3σ)6 (k=3, N=21) were found 20 µg L -1 for

Fe(III), 25 µg L -1 for Cu(II), 32 µg L -1 for Mn(II) and 15

µg L -1 for Zn(II). The calibration curves were linear in

the range of 0.4-10 µg L -1 for Fe(III), 0.5-8.0 µg L -1 for

Cu(II), 0.5-10 µg L -1 for Mn(II) and 0.1-7.0 µg L -1 for

Zn(II).

Table 2. Iron, zinc, manganese and copper concentrations in

certified reference material (NIST SRM 1515 Apple Leaves),

N=4

Element Certified

value (µg g -1)

Our value

(µg g -1)

Recovery

(%)

Cu 5.64 5.55±0.20* 98±2

Fe (83)a 80.7±2.5 97±1

Mn 54 52.1±1.6 96±2

Zn 12.5 12.2±0.9 98±2 a The value in the parenthesis is not certified, *mean±SD

Trace element concentrations of analyzed pekmez

samples were found in the range of5.7-20 µg g -1 for

iron, 0.75-3.3 µg g -1 for copper, 3.8-5.1 µg g -1 for zinc

and 0.90-5.4 µg g -1for manganese. The FAO/WHO has

set a limit for traces heavy metal intake based on body

weight. For an average adult (60 kg body weight), the

provisional tolerable daily intake (PTDI) for iron,

copper and zinc are 48 mg, 3 mg and 60 mg,

respectively7. The Institute of Medicine recommends

that intake of manganese from food, water and dietary

supplements should not exceed the tolerable daily upper

limit of 11 mg per day8. The intake of manganese in

analyzed samples is well below the tolerable daily upper

limit of 11 mg per day. The comparison of trace element

levels in pekmez samples with Turkish Standards and

literature values are given in Table 3. The results are in

agreement with Turkish Standards and literature values.

Table 3. Comparison of trace element levels in pekmez

samples with Turkish Standards andliterature values

Literature

values

Fe

(µg/g)

Cu

(µg/g)

Zn

(µg/g)

Mn

(µg/g)

Pekmez9 4.18–

12.96

0.91–

15.76

2.97–

4.08

-

Locustbean

pekmez10

2.66–

3.32

0.36–

1.14

2.86–

2.94

-

Pekmez5 6.89-28 0.34-

1.11

1.65-

6.01

-

Locustbean

pekmez5

3.17 0.51 4.61 -

Pekmez11 25 5 5 5

Thisstudy 5.7-20 0.75-3.3 3.8-5.1 0.90-5.4

CONCLUSION

Trace metals ions in analyzed pekmez samples are in

agreement with Turkish Standard (11). Iron, copper,

zinc and manganese levels in analyzed pekmez samples

were acceptable to human consumption at nutritional

and toxic levels. The microwave digestion method can


be used for determination of heavy metal ions in routine analysis in various pekmez and food samples.

ACKNOWLEDGEMENTS

The author would like to thanks to Gaziosmanpasa University and Turkish Academy of Sciences for financial support.

REFERENCES 1Yıldız, O.: Citak, D.: Tuzen, M.: Soylak, M. FoodChem.Toxicol.

2011, 49, 458-463. 2Tokalıoğlu, S.: Gürbüz, F. Food Chem. 2010, 123, 183–187. 3Altundag, H.: Tuzen,M.Food Chem. Toxicol. 2011, 49, 2800-2807. 4Tormen, L.:Torres, D.P.: Dittert, I.M.: Araujo, R.G.O.: Frescura,

V.L.A. Curtius, A.J. J. Food Compos. Anal. 2011, 24, 95–102.

5Acar, O.: Tunceli, A.: Turker, A.R. Food Anal. Met. 2016, DOI

10.1007/s12161-016-0516-4. 6Long, G.:Winefordner, J.D. Anal. Chem. 1983, 55, 712-724. 7Joint FAO/WHO, Expert committee on food additives. Summary and

conclusions, 53rd meeting, Rome, 1-10 June, 1999. 8National Research Council Recommended Dietary Allowances, 10th

ed. Washington, DC: National Academy Press, 1989. 9Akbulut, M.:Ozcan, M.M. Int. J. FoodSci. Nutr. 2009, 60(3), 231–

239. 10Karaca, I. Determination of vitamin and mineral in

fruitjuiceconcentrates, Msc. Thesis, Inonu University, Department of

Basic PharmaceuticalFaculty, Malatya, Turkey, 2009, p: 95-96 11TS 3792, Pekmez (Traditional Turkish grape juice concentrate),

2008.


Influence of Aluminium Introduced into Natural Zeolites on Arsenic Removal from Aqueous Medium

Ayten ATEŞ1*

1*Cumhuriyet University, Engineering Faculty, Department of Chemical Engineering Sivas, 58140, Turkey,


Natural zeolite (NZ) obtained from the Sivas-Yavu region of Turkey was modified by aluminium at different concentrations (0.5-1.5 wt. %) (Al2(SO4)3) (NZ(x), x: wt.% Al of NZ) using ion exchange method and aluminium introduction (Al-NZ) after NaOH treatment of natural zeolite. The adsorption capacity of natural and modified zeolites was determined for arsenic removal. The characterisations of the natural and modified zeolites were carried out by XRD, N2 sorption, and SEM-EDS. Introduction of aluminium into the NZ leads to a significant decrease of its surface area and microporosity. The maximum arsenic (As(V) adsorption capacity was achieved with the zeolite treated with 0.5 (wt. )% Al. More than this concentration of aluminium leads to a significant decrease in arsenic adsorption capacity of natural zeolite. The isotherm (the Langmuir and the Freundlich) models fit with the results obtained from arsenic adsorption on natural and modified zeolites. The results obtained show that the highest As(V) removal (18.8 mg/g) was found on Al-NZ, which is mostly due to effective introduction of aluminium into zeolite after NaOH treatment

Keywords:Arsenic, aluminium introduction, adsorption, natural zeolite

INTRODUCTION

The industrial activities and natural changes in the environment may lead to the formation of widespread water pollution, which is forced to research and develop technologies on the remediation of this pollution. Recently, previous studies have shown that ten million people are exposed to toxic heavy metals every day1. Among them, arsenic is one of the most toxic metals and its presence in underground water makes the water undrinkable. Arsenic existsin the form of trivalent arsenite (as H3AsO3

o and H2AsO3−) and pentavalent arsenate (as

H2AsO4− and HAsO42−)in natural waters depending on

various physical conditions (pH, temperature, solution composition and redox potential). However, arsenite corresponds to 60-99% of total arsenic in the water, which is more toxic than arsenate2–5. The researchers show that the As toxicity and its hazardous effects such as irritation of the digestive tract, vomiting and diarrhea, decreased production of erythrocytes and leukocytes, abnormal cardiac functions, blood vessel damage, liverand/or kidney damage and impaired nerve functions in hands and feeton human health6–9. Therefore, International World Health Organization (WHO), United States Environmental Protection Agency (EPA) and many local organizations strive to reduce the occurrence of arsenic in drinking water from 50 to 10 μg /L10,11.

Several methods have been reported in the literature for the removal of arsenic and other heavy metals from water. Among these methods, adsorption is a simple, inexpensive and easy to operate method when a suitable adsorbent is developed. For this purpose, although very different adsorbent types (such as single or multiple mixed metal oxides, phosphates, metal-based materials, biosorbents, etc.) is used, the natural adsorbents are preferred for arsenic removal because they are cheap and persistent. Among these natural materials, natural zeolites are used as effective adsorbents for remediation due to their mechanical and thermal properties. For this, Cedillo et al.12 reported that the adsorption of As (V) on modified clinoptilolite rich tuffs is dependent on the chemical nature of the loaded metal and the interaction between different metallic chemical species on the zeolite surface.As a result, studies on natural and modified zeolites have shown that the adsorption mechanism and capacity of zeolite depends on the type and charge of the zeolite framework, which is mostly related to the aluminium content of the zeolite, the size and shape of the pores, composition of the zeolite phase,the nature and concentration of cations located outside the framework as well as adsorption conditions (pH, temperature and concentration, etc.)13

.


In previous studies, the addition of Al to natural zeolites was studied by Kamal et al. 14 and Ates15, which significantly increased its Mn+2adsorption capacity In the present study, the natural zeolite obtained from Sivas-Yavu of Turkey is modified withaddition of Al with different concentrations via ion exchange method and Al introduction after NaOH treatment. The natural and modified zeolites are characterized by SEM, EDS, XRD andN2 adsorption-desorption. Effect of specific adsorption parameters on the removal of arsenic was studied and obtained data were fitted to isotherm models


Materials

The adsorption of As(V) on the natural zeolite obtained from Sivas-Yavu of Turkey was performed. The natural zeolite was first ball- milled to a particle size ranging from 0.25 mm to 0.5 mm, and dried in an oven at 120 °C overnight. Before using, the zeolite was washed and dried at 120 oC. A part of zeolite was treated in 2.5 M NaOH solution and obtained Zeolit 4A (Na-NZ). Al introduction into NaOH treated zeolite was performed using a solution of Al2(SO4)3 as reported by Kamali et al.14 and Ates15. In addition, a part of natural zeolite was modified with varying Al concentration(0.5- 1.5% (wt.)) using a solution of Al2(SO4)3)via ion exchange method. The samples were denoted as NZ(x), where x indicates Alpercentage (% wt.) content of natural zeolite. After NaOH treatment, Al loaded zeolite is called as Al-NZ. Characterization of adsorbents The chemical composition of natural and modified zeolite was analysed using energy-dispersive X-ray spectroscopy (EDS) (OXFORD INSTRUMENTS INCA X-Act/51-ADD0013) on a scanning electron microscope (SEM) (JEOL/JSM-6610). The morphology of the natural and modified zeolites was examined by a scanning electron microscope (SEM) (JEOL/JSM-6610). X-ray powder diffraction (XRD) patterns of the samples were recorded on a RigakuSmartLab X-ray diffractometer using non-monochromotographic Cu Kα1-radiation (40 kV, 40 mA, λ = 1.5). Scanning was in the range 5–65 °C of 2θ. The specific surface area and

micropore volume of the samples were measured using N2adsorption–desorption (AUTOSORB 1C) at − 196 °C. Prior to adsorption, the samples were evacuated until a pressure of 66.6 Pa at room temperature was reached, then heated up to 300 °C and evacuated until a pressure of 1.3 Pa was reached. This condition was maintained overnight. The surface area, total pore volume and micropore volume were determined by multipoint BET, t-plot and DR (Dubinin–

Radushkevic), respectively.

Adsorption experiments

The batch adsorption experiments were carried out in glass flasks (0.05 L) for 25- 200 mg/L of As(V) at varying pH (1- 9) at using a magnetic shaker at 25 °C at a constant agitation of 200 rpm.0.02 g of the adsorbent was used for each flask. After the reaction, suspensions were centrifuged at 5000 rpm for 3 min in order to separate the solution and the solids. The initial and non-adsorbed concentrations of As(V) in supernatants were determined by atomic absorption spectroscopy (AAS). After determination of optimum pH, the equilibriıum

time of adsorbents for As(V) was studied.


EDS analyses of the natural and modified zeolites are listed in Table 1.After alkaline treatment with 2.5 M NaOH solution, Al content of Al loaded zeolite is high. On the other hand, Al loading with ion exchange methode depends on Al content of solution and lower than that of NaOH treated sample. The difference should be a result of differences between methods. Although Al loaded with ion exchange method can exchange with exchangeable cations in the structure of the zeolite, Al can be introduced into framework of NaOH treated zeolite. Therefore, Al content of NaOH treated zeolite is higher than that of ion exchange method. Table 1. Composition of natural and modified zeolies determined by EDS. NZ Al-NZ NZ(0.5) NZ(1.0) NZ(1.5)

Si 79.6 70.6 32.6 29.0 29.3

Al 7.0 19.5 6.2 6.6 6.5

O - - 53.8 58.4 57.0

K 0.4 0.6 - 0.4 2.4

Ca 2.1 4.3 4.5 2.3 3.3

Mg 1.2 2.4 0.6 0.6 2.2

Fe 0.7 1.4 1.7 1.2 1.0

Na - - 0.7 1.4 - XRD patterns of natural and Al loaded zeolites are shown in Figure 1. Based on the Figure 1, clinoptilolite phase in the zeolite dissolves during the Al loading by ion exchange, and the quartz, mordenite and feldspar phases remain stable. However, the structure of natural zeolite can be stabile considerablyafter Al loading with ion exchange.On the other hand, after the treatment with NaOH, the peaks mostly disappeared due to the coating of surface with alumina in which the aluminium peak wasn't detected due to the likely formation of amorphous aluminium.


Figure 1. XRD paterns of natural and modified zeolites SEM images of natural and Al-loaded zeolites are shown in Figure 2. After treatment with NaOH, the pores of the zeolites are closed, and an aglomeration in the structure of zeolite is observed.This is also supported by the results of surface area and pore properties in Table 2.Both the results in Figure 3 and Table 2 show a significant reduction of surface area with Al loading. In addition, the pore diameters of the samples also increased.This may be a consequence of the dissolution of the micropores into mesopores during the treatment.

Figure 2. SEM images of natural and modified samples Table 2. Changes in surface areas and pore characteristics of NZ by the Al loading.

(a)

(b)

Figure 3. N2 adsorption–desorption isotherm (a) and differential pore size distribution (b) of natural and modified zeolites. Adsorption results

The adsorption of As (V) with the natural and Al modified zeolites is higher under acidic conditions.For this reason, the effect of pH on As (V) adsorption was studied and the results obtained are listed in Table 3. The adsorption capacity of natural and Al-loaded zeolites is highest at pH = 5. Therefore, the initial pH of the solution was chosen as 5 and was carried out at pH = 5 in all adsorption experiments.

5 15 25 35 45 55 65

2θo CuKα

NZClp

Clp

Mor

Qrz

Fel

Clp:ClinoptiloliteMor:MordeniteQrz:QuartzFel:Feldispate

NZ(0.5)

Al-NZ

Intensity

[a.u]

NZ(1.0)

NZ(1.5)

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

0.00 0.20 0.40 0.60 0.80 1.00

Vol

ume

adso

rbed

[cm

3g-1

] Relative pressure[P/Po][-]

NZ

NZ(0.5)

NZ(1.0)

NZ(1.5)

0.0E+00

2.0E-04

4.0E-04

6.0E-04

8.0E-04

1.0E-03

1.2E-03

1.0 100.0 10,000.0

Dv(

d)[c

m3 /

Å/g

]

Pore diameter (d) [Å]

NZ

NZ(0.5)

NZ(1.0)

NZ(1.5)

NZ-Y

NZ(0.5) NZ(1.0)

NZ(1.5)

Al-NZ

Sample SBETa

(m2 g-1) VTotal

b

(cm3 g-1) VMicro

b (cm3 g-1)

Dpc (Å)

NZ 62.4 0.14 0.027 94

Al-NZ 37.4 0.22 0.014 241

NZ(0.5) 30.4 0.18 0.012 117

NZ(1.0) 25.07 0.16 0.009 133

NZ-(1.5) 22.8 0.08 0.008 72 aMultipoint BET method; bVolume adsorbed at p/p0 = 0.99; cMicropore volume calculated by DR method


The effect of contact time and adsorption isotherms The adsorption equilibrium time of As (V) was studied with natural and Al loaded zeolites and the adsorption time of As (V) in NZ and Al-NZ was 120 min and it is 200 min in NZ (0.5). Longer equilibrium time of As (V) in NZ (0.5) can be a result of the diffusion problem because its pore diameter is lower than those of NZ and Al-NZ. Table 3. Effect of initial solution pH on arsenic removal (mg / g) with natural and Al loaded zeolites [CAso=100 mg/L and adsorbent concentration: 1 g/L]

Based on the As (V) data in different concentrations with time, the Langmuir and Freundlich models were fitted to adsorption isotherms and adsorption constants obtained from the isotherms are presented in Table 4. The As (V) adsorption order is Al-NZ <NZ> NZ (0.5). The As (V) adsorption order is Al-NZ <NZ> NZ (0.5). Higher regression coefficient for NZ (0.5) and Al-NZ in Table 4 suggests that the Freundlich model is more suitable for arsenic removal than the Langmuir model. Whereas the Langmuir model assumes the adsorbent with a homogenous surface, the Freundlich models describes adsorption on adsorbents with heterogeneous surface. As explained above, because all samples contain several phases and cations, they have different adsorption sites with different sorption energies. Therefore, As (V) is adsorbed on homogeneous surfaces of NZ and fits to the Langmuir model. On the other hand, the Al-loaded zeolite fits to the Freundlich isotherm model because the Al in the structure of natural zeolite allows the adsorption on a heterogeneous surface. Table 4. Adsorptionisothermsfor As (V) adsorption of adsorbents

Table 4 shows thatqmax is 12, 18 mg g-1 and 12.8 for NZ, Al-NZ and NZ (0.5), respectively. Increasing Al content of natural zeolite increases As (V)

adsorption.This confirms that Al species in the structure is responsible for As (V) adsorption. Comparing the results with the literature shows that natural and Al-loaded zeolites have higher adsorption capacity than those reported in the literature4,12,16–20. The difference between the literature and the results reported here can be a result of differences in the origin, composition and crystal structure of natural zeolite.

CONCLUSION

The natural zeoliteobtained from the Sivas-Yavu region was modified by ion exchange with Al at different concentrations and by aluminium loading after alkali treatment with NaOH.Natural and modified zeolites were tested for adsorption of the arsenic from aqueous solutions.The modification applied can changethe structure and composition of the zeolite significantly and increases the zeolite’s arsenic adsorption capacity.The highest As (V) adsorption capacitywas found on NaOH-treated zeolite Al loaded zeolite

ACKNOWLEDGEMENTS

This project was carried out with thefinancial support of Cumhuriyet University Scientific Research Fund (CÜBAP-M-492) and TÜBİTAK (113M813 of project).

REFERENCES

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disease. British Medical Bulletin. 2003, pp 1–24. (2) Wang, S.; Mulligan, C. N. Occurrence of arsenic

contamination in Canada: Sources, behavior and distribution. Sci. Total Environ.2006, 366 (2–3), 701–721.

(3) Vaughan, R. L.; Reed, B. E. Modeling As(V) removal by a iron oxide impregnated activated carbon using the surface complexation approach. Water Res.2005, 39 (6), 1005–1014.

(4) Tuna, A. Ö. A.; özdemir, E.; şimşek, E. B.; Beker, U.

Removal of As(V) from aqueous solution by activated carbon-based hybrid adsorbents: Impact of experimental conditions. Chem. Eng. J.2013, 223, 116–128.

(5) Smedley, P. L.; Kinniburgh, D. G. A review of the source, behaviour and distribution of arsenic in natural waters. Applied Geochemistry. 2002, pp 517–568.

(6) Muhammad, S.; Tahir Shah, M.; Khan, S. Arsenic health risk assessment in drinking water and source apportionment using multivariate statistical techniques in Kohistan region, northern Pakistan. Food Chem. Toxicol.2010, 48 (10), 2855–2864.

(7) Rahman, M. M.; Naidu, R.; Bhattacharya, P. Arsenic contamination in groundwater in the Southeast Asia region. Environ. Geochem. Health2009, 31 (0), 9–21.

(8) Thundiyil, J. G.; Yuan, Y.; Smith, A. H.; Steinmaus, C. Seasonal variation of arsenic concentration in wells in Nevada. Environ. Res.2007, 104 (3), 367–373.

(9) Lamm, S. H.; Kruse, M. B. Arsenic ingestion and bladder cancer mortality - What do the dose-response relationships suggest about. Hum. Ecol. RISK Assess.2005, 11 (2), 433–

450.

pH NZ Al-NZ NZ(0.5) NZ(1.0) NZ(1.5)

1.5 14.2 1.0 6.2 3.8 2.4

3.0 18.8 14.8 6.4 3.4

5.0 19.0 24.8 8.9 n.d

7.0 15.4 9.0 0.8 n.d

9.0 6.70 16.9 9.0 n.d

Sample Freundlich izoterm Langmuir izoterm

kF (L/g)

1/n R2 qmak (mg/g )

b (L/mg)

R2

NZ 1.74 0.34 0.92 12.33 0.02 0.96

Al-NZ 0.66 0.58 1.00 18.83 0.01 0.99

NZ(0.5) 1.31 0.41 0.99 12.8 0.02 0.98


(10) McArthur, J. M.; Ravenscroft, P.; Banerjee, D. M.; Milsom,

J.; Hudson-Edwards, K. A.; Sengupta, S.; Bristow, C.; Sarkar, A.; Tonkin, S.; Purohit, R. How paleosols influence groundwater flow and arsenic pollution: A model from the Bengal Basin and its worldwide implication. Water Resour. Res.2008, 44 (11).

(11) Sengupta, S.; Mcarthur, J. M.; Sarkar, A.; Leng, M. J.; Ravenscroft, P.; Howarth, R. J.; Banerjee, D. M. Do ponds cause arsenic-pollution of groundwater in the Bengal Basin? An answer from West Bengal. Environ. Sci. Technol.2008, 42 (14), 5156–5164.

(12) Jiménez-Cedillo, M. J.; Olguín, M. T.; Fall, C.; Colín, a. Adsorption capacity of iron- or iron-manganese-modified zeolite-rich tuffs for As(III) and As(V) water pollutants. Appl. Clay Sci.2011, 54 (3–4), 206–216.

(13) Margeta, K.; Stefanović, Š. C.; Kaučič, V.; Logar, N. Z. The potential of clinoptilolite-rich tuffs from Croatia and Serbia for the reduction of toxic concentrations of cations and anions in aqueous solutions. Appl. Clay Sci.2015, 116–117, 111–119.

(14) Kamali, M.; Vaezifar, S.; Kolahduzan, H.; Malekpour, A.; Abdi, M. R. Synthesis of nanozeolite A from natural clinoptilolite and aluminum sulfate; Optimization of the method. Powder Technol.2009, 189 (1), 52–56.

(15) Ates, A. Role of modification of natural zeolite in removal

of manganese from aqueous solutions. Powder Technol.2014, 264, 86–95.

(16) MacEdo-Miranda, M. G.; Olgu??n, M. T. Arsenic sorption by modified clinoptilolite-heulandite rich tuffs. J. Incl. Phenom. Macrocycl. Chem.2007, 59, 131–142.

(17) Ramesh, a.; Hasegawa, H.; Maki, T.; Ueda, K. Adsorption of inorganic and organic arsenic from aqueous solutions by polymeric Al/Fe modified montmorillonite. Sep. Purif. Technol.2007, 56 (1), 90–100.

(18) Hu, X. jiang; Wang, J. song; Liu, Y. guo; Li, X.; Zeng, G. ming; Bao, Z. lei; Zeng, X. xia; Chen, A. wei; Long, F. Adsorption of chromium (VI) by ethylenediamine-modified cross-linked magnetic chitosan resin: Isotherms, kinetics and thermodynamics. J. Hazard. Mater.2011, 185 (1), 306–

314. (19) Jeon, C.-S.; Baek, K.; Park, J.-K.; Oh, Y.-K.; Lee, S.-D.

Adsorption Characteristics of As(V) on Iron-Coated Zeolite. J. Hazard. Mater.2009, 163 (2–3), 804–808.

(20) Dousová, B.; Grygar, T.; Martaus, A.; Fuitová, L.; Kolousek, D.; Machovic, V. Sorption of As(V) on aluminosilicates treated with Fe(II) nanoparticles. J. Colloid Interface Sci.2006, 302 (2), 424–431.


Photobromination of Monobromoindanones and Efficient Synthesis

of 5-bromo-2,2 dimethoxyindan-1,3-dione

İbrahim Halil BAYDİLEK*a, Raşit Fikret YILMAZ

a, Yavuz DERİNa, Ömer Faruk TUTARa,

Ahmet TUTARa

a.Sakarya University, Faculty of Art and Science, Department of Chemistry

*[email protected]

Keywords: Photobromination, indanone, bromoindanone, ninhydrine,5-bromo-2,2-dimethoxyindan-1,3-dione

INTRODUCTION

Brominated arylhydrocarbones are important

class of molecules in synthesis of many different organic compounds. These compounds have many industrialy applications, for instance, pestisides, fire retardants, plastics and pharmaceutical chemicals In addition to that these molecules are essential intermatiates for synthesis of the organometalic compounds and crucially needed for coupling reactions. Indanone skelotone can be found in natural products and also obtained synthetically. Indanone derivatives are important class of molecules showing biological activities including antifungal, antibacterial, antiproliferative, antiviral activity againist hepatitis C virus1-5.

Ninhydrin (2,2-dihydroxyinden- 1,3-dione) is

famous in particular because of its color forming reaction with amins. Due to this property, numerous ninhydrin derivatives and analogues6 have been published for their use as latent fingerprint dedectors in forensic science. Ninhydrins are of increasing interest in photochemistry and versatile intermediates in the synthesis of heterocyclic compounds, highly substituted imidazol, and substituted furans7. Bromoninhydrin is important precursors for synthesis of ninhydrin derivatives and analogues. Bromoninhydrins are usually prepared by oxidation of indan-1- ones which are very expensive starting material.

In this study, synthesis of di and tri

bromoindenones was done via photochemical bromination reaction starting from monobromoindanones. In addition, for the synthesis of 5-bromoninhydrin, efficient method was carried out starting from indan which is cheap and availible. This process involved four steps which are ionic bromination of the indane, photochemical bromination of 5-bromoindane, silver-supported hydrolysis of

hexabromoindane, oxidation of bromoketons with DMSO and finaly exchange of hidroxyl with methoxide. Structures of the final products were elucidated by 13C, 1H-NMR spectroscopy and FT-IR spectroscopy.


A. General procedure of photobromination of mono-bromoindanones

Photobromination of 5-bromindanone (2)

(0,3g, 1,42 mmol) in 15 ml carbon tetrachloride was carried out adding dropwise 3,2 equivalent bromine solution at room temperature for 30 minute while irradiated at 150W with a projector lamp. It was understood from TLC that the reaction was completed. Exceed of bromine and HBr generated as byproduct were evaporated. Then trietilamine (TEA) (0,16g, 1,56 mmol) in carbon tetrachloride was dropped into the crude product disolved in carbon tetrachloride in an ice bath and finally ice bath was removed and the mixture was stirred overnight. Precipitation was occured and removed by filitration. After the mixture was concentarated in vacuo, it was passed through silica gel coloumn to yield 2,3,5 tribromoindenone (2a). 4-bromindanone (1) was photobrominated using 2,2 equivalent molecular bromine to yield 2,4 dibromoindanone (1a) while this prosedure applied to 5-bromindanone was repeated for photobromination of 6-bromoindanone (3) to give 2,3,6 tribromoindenone (3a) (Scheme 1)


Scheme 1. Photobromination of monobromindanones

B. Synthesis of 5-bromo-2,2-dimethoxyindane-1,3-dione

Indane was brominated using 0.5 equivalent

molecular bromine in dark by ionic bromination for 2 hours at room temperature and extracted with CH2Cl2 then concentrated in vacuo and 5-bromindanone was gained by destilation of oily crude product.

While 7 equivalent bromine in CCl4 was droped into solution of 5-bromindanone in CCl4, the mixture was irradiate with 500W in special reactor for 16 hours at 77 C. After HBr and exceed bromine were removed, residue was passed through silica coloumn with hexane to gain the product and this product was treated with silver (I) nitrate in acetone/water then again Silica coloumn chramotography was applied to yield tribromindenone which later oxidized with dry DMSO at 170 C, 200ml water added , extracted with EtOAc and organic solvent was evaporated to get (4a-1). Finally hidroxyl groups were exchanged with methoxy groups to gain 5-bromo-2,2-dimethoxyindanone-1,3-dione (4a-2).

Scheme 2. Synthesis of 5-bromo-2,2-methoxyindan-1,3-dione

Spectral Values

1a 1H-NMR(300MHz,CDCl3)= ppm 7.8 (s, 1H), 7.35-7.45 (m, 2H), 7.05 – 7.12 (m,1H). IR(KBr, cm-1); 3440, 3078, 2923, 2854, 1728, 1593, 1458, 1358, 1265, 1111, 872, 748, 578.

2a

1H-NMR(300MHz,CDCl3 )= ppm 7.50-7.46 (m, 1H), 7.34-7.26 (m,2H). 13C NMR (75 MHz,CDCl3) = ppm 185.64, 144.83, 144.28, 132.81, 129.63, 127.74, 124.87, 124.28, 123.99. IR(KBr, cm-1) 3417, 3082,, 1724, 1593, 1543, 1442, 1400, 1338, 1203, 1091, 1057, 933, 875, 833, 764, 690.

3a

1H-NMR(300MHz,CDCl3 )= ppm 7,64-7,56(m,2H) 7.10-7.06(m, 1H). 13C-NMR(75 MHz,CDCl3) 185.76, 146.48, 141.32, 136.96, 130.52, 126.48, 124.50, 122.60, 122.55. IR (KBr, cm-1) 3413, 1720, 1585, 1535, 1442, 1400, 1257, 1165, 1099, 833, 764, 667, 575.

4a-1

1H-NMR(300MHz, DMSO-d6)= ppm 7.89-7.93 (m,2H), 7.68 (d, J=8,1,1H),7.38 (s, 2H) 13C NMR (75 MHz, DMSO-d6)= ppm 87.7, 125.9, 126.7, 131.5, 137.2, 139.8, 140.1, 195.8, 196.1 IR (KBr, cm-1) 3323, 1753, 1717, 1583, 1173.

4a-2

1H NMR (CDCl3, 300 MHz) = ppm 8,13 (d, J = 1,73 Hz, 1H), 8,07 (dd, J = 8,8 Hz, J = 1,7 Hz, 1H), 7,86 (d, J = 8,8 Hz, 1H), 3,65 (s, 6H) .13C NMR (CDCl3, 75 MHz) = ppm 192.65, 192.38, 140.67, 140.15, 138.02, 132.71, 127.58, 125.85, 91.00, 52.02

CONCLUSION

In this study, 2,4 dibromoindanone (1a), 2,3,5

tribromoindenone (2a), 2,3,6 tribromoindenone (3a) were synthesised by photochemical bromination using molecular bromine at room temperature. Synthesis of 5-bromo-2,2-dihydroxyindan-1,3-dione (4a-1) and 5-bromo-2,2-dimethoxyindan-1,3-dione (4a-2) was done effectively

Final products were characterized by 1H, 13C-

NMR spectroscopies and IR- spectroscopy.


ACKNOWLEDGEMENTS

This study is supported by the Scientific and Technological Council of Turkey (TÜBİTAK, KBAG-114Z176) and the Scientific Research Projects Unit of Sakarya University (BAP-2014-02- 04-010).

REFERENCES 1Cakmak, O.; Erenler, R.; Tutar, A.; Celik, N. J. Org. Chem. 2006, 71, 1795– 1801. 2Tutar, A.; Cakmak, O.; Balci, M. J. Chem. Res. 2006, 507–511. 3R. Erenler, I. Demirtas, Bulent Buyukkidan, O. Cakmak, J. Chem. Res., 2006 753-757. 4R. Erenler, O. Cakmak, J. Chem. Res., 2004, 566-569. 5H. L. Anderson, C. J. Walter, A. Vidal-Ferran, R. A. Hay, P. A. Lowden, J. K. M. Sanders, J. Chem. Soc., Perkin Trans. 1995, 1, 18 2275-2279 6Tatsugi, J. And Izawa Y. Synt. Commun., 1998, 28 (5), 859-864. 7Hark, R.R., Houze, D.B., Petrovskaia, O.,Joullie M.M. Can. J. Chem. 2001, 79, 1632-1634.


A Study on Thermodynamical Proporties Of Melatonin in Blood by Using DFT and HF

Faik GÖKALP*

* Kırıkkale University, Faculty of Education, Department Of Mathematics and Science Education,

Science Education Division, Yahşihan/Kırıkkale, Turkey

Absract Melatonin, the important hormone, produced by the pineal gland, not only adjust circadian rhythm, but also has antioxidant, anti-ageing and immunomodulatory properties. in many other parts of the body, including the eyes, bone marrow, gastrointestinal tract, skin and lymphocytes. Melatonin influences many cell and can be traced in membrane, cytoplasmic, mitochondrial and nuclear compartments of the cell Melatonin is a potent scavenger of free radicals and exerts direct inhibition of cancer growth.When we compare the thermodynamical values of Melatonin,Seratonin and Tryptophan. These can be seen by looking as theoritical values getting from DFT and HF methods. Melatonin prevents cell damage and important substance for stopping cancer ilness and the experimental datas are suitable with our theoritical values.

Keywords : Melatonin, Seratonin, Tryptophan, DFT and HF

INTRODUCTION

Melatonin (N-acetyl-5-methoxytryptamine) is a natural substance that has been identified in most living species, involving bacteria and other unicellular microorganisms, plants and animals, as well as in humans [1,2]. It is possible that the first function of melatonin was related to its activity as a direct and indirect antioxidant. Different herbs that include high levels of melatonin have been used by Chinese since early times to retard ageing and to treat diseases releated with the production of free radicals [3]. Both ageing and free radical production are mainly factors included in all steps of carcinogenesis, forming initiation, promotion and progression of neoplastic

disease [4]. The distribution of melatonin in nature is compatible with the view that it can be one of the natural molecules that are effective in treating neoplastic [5‐9] as well as degenerative diseases [10,11].

‘’Endogenous synthesis of melatonin displays a pronounced circadian rhythm. The production of melatonin from the amino acid tryptophan, via its conversion to serotonin. Serotonin is then acetylated to form N‐acetylserotonin by the enzyme arylakylamine N‐ acetyltransferase (AANAT). N‐acetylserotonin is converted into melatonin by the enzyme hydroxyindole‐O‐methyltransferase (HIOMT). The enzymatic machinery for melatonin


biosynthesis was first identified by Axelrod in the pinealocytes’’[12]. Melatonin is taken under control by exposure to cycles of light and dark, independent of sleep. And its synthesis is inhibited by exposure to light; production is stimulated during periods of darkness by way of a multi-synaptic neural pathway connecting the pineal gland to the external environment via the retina Serum melatonin levels are highest prior to bedtime. In addition to the pineal gland, some melatonin is synthesized in the retina, bone marrow, gastrointestinal tract [13-16]. The gut appears to produce proportionally more melatonin than the pineal gland.

Melatonin is a powerful scavenger of reactive oxygen species (ROS), forming the hydroxyl and peroxyl radicals, singlet oxygen and nitric oxide [18-20]. With scavenging ROS, melatonin stimulates the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and catalase. Melatonin reduces lipid peroxidation more efficiently than either vitamins C or E [21-24].

Different cancer types have shown to be responsive to melatonin, involving breast cancer, lung cancer, metastatic renal cell carcinoma, hepatocellular carcinoma, and brain metastases from solid tumors, at dosages of 10-50 mg daily. Applying of the melatonin dosage appears to be important, with the most effective protocol being a diurnal cycle similar to the physiological rhythm of melatonin secretion. In a study of metastatic breast cancer patients who had not responded to initial therapy with tamoxifen, 20 mg of melatonin was administered daily in the evening along with tamoxifen. A partial response was seen in 28 percent of patients whose disease would have otherwise been

expected to progress rapidly. In those who responded clinically, significant declines were also found in serum levels of the tumor growth factor IGF-1 (p<0.001). This response was irrespective of estrogen- receptor status [25-28].

‘’The understanding of the immune changes in the elderly can provide new insights into the complex relationship between immunity and cancer. In this respect, the decline in the production of melatonin with aging was suggested to play an important role in triggering immunosenescence, especially ageassociated neoplastic diseases. Any search for a therapeutic agent that can improve the quality of life in the elderly depends upon the identification of substances that have antioxidant qualities. As melatonin has been identified as a natural antioxidant with immunoenhancing properties, it has the potential of becoming an effective therapeutic substance in preventing neoplastic growth ‘(29).

Several clinical trials have examined the therapeutic usefulness of melatonin in several types of cancer. The use of melatonin as an adjuvant therapy seems to be very useful for early stages than for advanced and metastatic cancers [30-31]. Use a strongly helpful aid for side effects caused by chemotherapy and radiotherapy administration was also reported [32-33]. Moreover, all the

investigations mentioned documented the very low toxicity of melatonin over a wide range of doses. On the basis of this preliminary studies, it seems that melatonin administration may be beneficial for oncological subjects [34–37]. It is significant atoxic, apoptotic, oncostatic, angiogenetic, differentiating and


antiproliferative properties against all solid and liquid tumors [38].

METARIALS AND METHODS

The electronic structures of melatonin,seratonin and tryptophan are commonly studied by DFT and HF, included in Gaussian 09. A pure DFT and HF method, containing Becke’s gradient correction for

exchange, and RB3LYP methods were used for geometry optimization. In the case of the RB3LYP functional, the non-local correlation was provided by the LYP expression, and the correction was carried out by means of the 6-31+g(d,p) functional. The thermodynamical values in blood and gas were calculted by using DFT and HF method.


In Table 1, Tryptophan, Seratonin and Melatonin’s HOMO, LUMO, ∆(HOMO-LUMO), Dipol moment and free energy values by Using DFT were given.

Table 1. Tryptophan, Seratonin and Melatonin’s HOMO,

LUMO, ∆(HOMO-LUMO), Dipol moment and free energy values in blood by Using DFT (The values of free energy are given as Hartree, 1Hartree:=627.5095 kcal. mol-1). Tryptophan Seratonin Melatonin

HOMO -0,00296 -0,02420 -0,00082

LUMO 0,00700 0,00203 0,00638

∆(HOMO-

LUMO)

-0,00996 -0,02623 -0,00720

Dipol Moment

4,48930 0,84750 9,31760

∆G (Hartree) -686,25612 -572,90425 -764,82640

In Table 2, Tryptophan, Seratonin and

Melatonin’s HOMO, LUMO, ∆(HOMO-LUMO), Dipol moment and free energy values in blood by Using HF were given.


LUMO, ∆(HOMO-LUMO), Dipol moment and free energy values in blood by Using HF (The values of free energy are given as Hartree, 1Hartree:=627.5095 kcal. mol-1). Tryptophan Seratonin Melatonin

HOMO -0.29075 -0.27876 -0.28042

LUMO 0.06713 0.06885 0.06571

∆(HOMO-

LUMO)

-0.35788 -0.34761 -0.93752

Dipol

Moment

4.5376 0.9140 9.0843

∆G

(Hartree)

-

682.2485276

-

569.4790536

-

760.3035733


Melatonin’s HOMO, LUMO, ∆(HOMO-LUMO), Dipol moment and free energy values in gas form by Using HF were given.


Table 3. Tryptophan, Seratonin and Melatonin’s HOMO, LUMO, ∆(HOMO-LUMO), Dipol moment and free energy values in gas form by Using HF (The values of free energy are given as Hartree, 1Hartree:=627.5095 kcal. mol-1). Tryptophan Seratonin Melatonin

HOMO -0.28599 -0.26591 -0.27529

LUMO 0.12795 0.13895 0.13434

∆(HOMO-

LUMO)

-0.41394 -0.40486 -0.40963

Dipol

Moment

3.3359 0.7217 6.8401

∆G

(Hartree)

-682.014506 -569.260190 -760.013994


Melatonin’s HOMO, LUMO, ∆(HOMO-LUMO), Dipol moment and free energy values in gas form by Using DFT were given.


LUMO, ∆(HOMO-LUMO), Dipol moment and free energy values in gas form by Using DFT (The values of free energy are given as Hartree, 1Hartree:=627.5095 kcal. mol-1). Tryptophan Seratonin Melatonin

p -0.01241 -0.00062 -0.00641

LUMO 0.00845 0.03850 0.02888

∆(HOMO-

LUMO)

-0.13255 -0.03912 -0.03529

Dipol

Moment

3.1435 0.6467 6.7104

∆G

(Hartree)

-686.206993 -572.861281 -764.775479

CONCLUSION

When we looked the differences of HOMO-LUMO values of Tryptophan, Seratonin and Melatonin are -0,00996, -0,02623 and -0,00720. The most stable one is Seratonin. The least stable one is Melatonin. So melatonin is eager to give reaction. According to dipol moment’s values

Melatonin, 9,31760, is more soluble in blood than he others. Gibbs free energy value of Melatonin, -764,82640 Hartree, is also higher than others. When we compered the gas and blood form by using both DFT and HF; The

values of them are near to each other. We can say that my results are true as methotodical. Therefore, We conclude that melatonin is the best antioxidant. This proporties of it, prevent cell damage and important substance for stopping cancer ilness can be said. The experimental works are suitable with our theoritical values.

ACKNOWLEDGEMENTS

The calculations are carried out on the High-Performance Computing Center and Gaussian 09W programs of Kırıkkale University. This study is supported by the Scientific Research Projects of Kırıkkale University (BAP- 2016/001-096).

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6. Miller S.C., Pandi‐Perumal S.R., Esquifino A.I., Cardinali D.P., Maestroni G.J., The role of melatonin in immuno‐enhancement: potential application in cancer, Int. J. Exp. Pathol., 2006,87:81‐7. 7. Anisimov V.N., Popovich I.G., Zabezhinski M.A., Anisimov S.V., Vesnushkin G.M., Vinogradova I.A., Melatonin as antioxidant, geroprotector and anticarcinogen, Biochim Biophys Acta, 2006, 1757:573‐89. 8. Jung B., Ahmad N., Melatonin in cancer management progress and promise, Cancer Res., 2006, 66:9789‐93. 9. Srinivasan V., Spence D.W., Pandi‐Perumal S.R., Trakht I., Esquifino A.I., Cardinali D.P., et al., Melatonin, environmental light, and breast cancer, Breast Cancer Res. Treat, 2008, 183 (3):339‐50. 10. Reiter R.J., Melatonin, active oxygen species and neurological damage, Drug News Perspect, 1998, 11:291‐6. 11. Axelrod J., The pineal gland, a neurochemical transducer, Science, 1974, 184:1341‐8. 12. Iuvone P.M., Brown A.D., Haque R., et al., Retinal melatonin production: role of proteasomal proteolysis in circadian and photic control of arylalkylamine N-acetyltransferase, Invest Ophthalmol Vis Sci, 2002, 43:564-572. 13. Conti A., Conconi S., Hertens E., et alEvidence for melatonin synthesis in mouse and human bone marrow cells, J Pineal Re, ., 2000, 28:193-202. 14. Aust S., Thalhammer T., Humpeler S., et alThe melatonin receptor subtype MT1 is expressed in human gallbladder epithelia, J Pineal Res., 2004, 36:43-48.

15. Reiter R.J., Tan D.X., Qi W.B., Suppression of oxygen toxicity by melatonin, Zhongguo Yao Li Xue Bao, 1998,19:575-581. 16. Bromme H.J., Morke W., Peschke D., et al., Scavenging effect of melatonin on hydroxyl radicals generated by alloxan. J Pineal Res, 2000, 29:201-208. 17. Pieri C., Marra M., Moroni F., et al., Melatonin: a peroxyl radical scavenger more effective than vitamin E, Life Sci, 1994,55:PL271-276. 18. Sewerynek E., Reiter R.J., Melchiorri D., et al., Oxidative damage in the liver induced by ischemia-reperfusion: protection by melatonin, Hepatogastroenterology, 1996, 43:898-905. 19. Noda Y., Mori A., Liburdy R., Packer L., Melatonin and its precursors scavenge nitric oxide, J Pineal Res, 1999,27:159-163. 20. Antolin I., Rodriguez C., Sainz R.M., et al., Neurohormone melatonin prevents cell damage: effect on gene expression for antioxidant enzymes, FASEB J, 1996, 10:882-890. 21. Barlow-Walden L.R., Reiter R.J., Abe M., et al., Melatonin stimulates brain glutathione peroxidase activity, Neurochem Int, 1995,26:497-502. 22. Montilla P., Tunez I., Munoz M.C., et al., Antioxidative effect of melatonin in rat brain oxidative stress induced by Adriamycin, Rev Esp Fisiol, 1997, 53:301-305. 23. Gitto E., Tan D.X., Reiter RJ, et al., Individual and synergistic antioxidative actions of melatonin: studies with vitamin E, vitamin C, glutathione and desferrioxamine (desferoxamine) in rat liver homogenates, J Pharm Pharmacol, 2001, 53:1393-1401.


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The Investigation of Dyeing Kinetics of Polyamide Fiber with Acid

Dyes under The Microwave Conditions

Murat TEKER* Hilal G. TEKER ALŞAN, Hatice ÖKER

*Department of Chemistry, Faculty of Art and Science, Sakarya University, TR-54187, Sakarya, Turkey

[email protected]

Abstract In this study were investigated dyeing of polyamide fiber with acid dyes in the microwave media. Microwave media studies power of different microwave, concentration of dyeing, period of dyeing, pH of dyeing and flotte ratio the changes were evaluated to staining intensity. Microwave levels were chosen as the five level, each level of the dyeing results of K/S ratios were analyzed. In the dyeing according to the severity of the staining intensity, dye concentration of 1% was choosen in dyeing. Severty of dyeing were increased microwave with increasing of levels. Also increased in direct proportion to the duration of dyeing was observed.

Keywords: polyamide, microwave, acid dye

INTRODUCTION

The first synthetic polymer in the world is in

the polyamide structure and is supplied by the manufacturer to the market with the name nylon1. About 26 million tonnes of nylon fiber present in the world market are filament and 675 million tonnes are cut fiber2 . Polyamides are known for their high strength and high abrasion resistance, high resilience to initial reversion and low moisture3. Polyamide fiber is painted with different dyeing methods. The squeezing method is a long flotte coloring. Rapid drying is required to prevent the paint from spreading smoothly in all directions (to prevent migration)4,5.

The first applications related to microwave have started in the field of food and have been applied in various industrial fields in recent years. The first microwave experiment on textiles began to be used practically by a machine which was exhibited by The Ichikin Company at the OTEMAS 81 (Japan) Exhibition in the name of Apolloteks Electron Reactor.The machine exhibited in the Fair was developed for polyester fabrics6.

Many textile dyeing process includes initially

the dye transition from the aqueous solution to the fiber surface. This event is adsorption. Then dye molecules diffuse into the fiber. Depending on the internal structure of the fiber it would form as transition to between polymer molecules or to the gap. This diffusion

step is the step that determines the rate of diffusion. Adsorption and then penetration of dye into the fiber materials are called absorption7,8. Dye diffusion of fiber depends on the pH, temperature and chemical auxiliaries used of the dyebath7. Adsorption is a reversible process. Dyes can be returned to the aquatic environment during washing the material. This is defined as the desorption. Apart from direct absorption dyeing of fibers can include two steps. First the dyestuff can be precipitated in fiber second a chemical reaction between the fiber and dyestuffs. These two methods are irreversible processes that lead to better wash fastness8. Examining the diffusion kinetically that is the slow step of staining and determination of dyeing kinetics was studied by many researchers. Dye diffusion into the fiber is compatible with Fick's law.

According to Fick's second law, the dye diffusion flux (mol/m2s) into the fibers per unit area is proportional to concentration gradient in this region (dc/dx, mol/mm) and diffusion coefficient (D, m2/s)8. Diffusion to be into a cylinder (or filaments) of infinite length that has radius r can be axplained by the Hill equation.


In equation, Mt the quantity of dyestuff on the fibers at time t, M∞ the quantity of dyestuff on the fiber in

equilibrium, D diffusion coefficient, r represents the radius of the fiber.qn shows the positive roots of zeroth order Bessel function9. In the case of (Dt/r2)<<1 it will reduce the equation as known Crank Equation10,11.

t versus (Mt/M∞) is plotted and then diffusion coefficients can be determined from obtained slope of the line10,11. According to the Kubelka-Munk theory, There is a linear relationship between the concentration of the dyestuff on a dyed textile material and K/S values. In this case the values of (K/S)t / (K/S)∞ can be written instead of the values of Mt/M∞

11,12. Kubelka-Munk equation the most important mathematical expression that has been developed to measure the color of the dyed textile material. For a material dyed the resulting graph is far from being linear by concentration plotted against reflectance at a specific wavelength. But the required linear relationship is established as instrumental with Kubelka-Munk equation13. Kubelka-Munk equation:

K/S is the scattering coefficient and It is

directly related to the dye concentration. R is the reflectance of the fabric at the maximum absorption wavelength13,14.Microwaves are located between infrared and radio waves in the electromagnetic spectrum. They are electromagnetic waves have frequencies between 300 MHz and 300 GHz. The wavelength of the microwaves is between 1 mm and 1 m. The microwaves are the type of electromagnetic energy Characterized by electrical and magnetic fields perpendicular to each other and non-ionizing. It leads to movement of molecules or ions. It can be projected, transmitted, absorbed and its absorption leads to the heat absorbed in material production15. Microwave energy penetrates into the sample and generates the internal heat. Its temperature gradient is minimum, creates volumetric heating and allows selective heating in the mixtures. Being high of the distribution factor which is the ratio of the dielectric loss factor and the dielectric constant shows that the samples take the microwave energy and are easily influenced by microwave. The second effect is ionic conduction. Ionic conduction is migration of dissolved or vibrating ions with the effect of changing electric field. With ionic conduction, it will accelerate the warming of the solution16.


In the experimental work, 100% polyamid knitted fabric was used. C.I.Acid Orange 33 and C.I.Acid Violet 90 were used in the dyeing.

Figure 1. IsolanYellow2SRL (C.I.AcidOrange 33)

Figure 2.Isolan Acid Violet 2SB(C.I.AcidViolet90)

KUM-1225 model Kumtel brand microwave (max.1150 W of power) and Color Eye S 7000 A model Gretag Macbethbrand Spectrophotometer were used in the study.

Experimental studies have been done according

to dyeing period, flotte ratio, equalizer concentration, pH and dye intensity.

Dyeing solution prepared at 1/50 flotted, 1 g/L equalizer, pH = 4.5 and 1% dyestuff concentration have been done At five different levels of microwave energy(195.5-460-759-977.5-1150 watt) in the 5 and 10 minutes. Dyeing results are shown in Figures 3 and 4.


Figure 3. Dyeing with C.I. Acid Orange 33 in 5 and 10 minutes.

Figure 4. Dyeing with C.I. Acid Violet 90 in 5 and 10

minutes.

Experiments were carried out at 1/20, 1/30, 1/50, 1/75 and 1/100 liquor ratios with 1% dye solution and pH = 4.5 and by using 1 g/L equalizer. Microwave studies were carried out at 759 watts and 5 minutes. Dyeing results are shown in Figures 5 and 6.

Figure 5. Dyeing with C.I. Acid Orange 33 in varying liquor ratios

Figure 6. Dyeing with C.I. Acid Violet 90 in varying liquor(flotte) ratios

In dyeing studies microwave power level (759 watts) and depending on the amount of equalizer were used %1 dye. Experiments were carried out at pH = 4.5 and 1/50 flotte ratio with 0.2, 0.5, 0.7, 1, 1.5 g/L of equalizer and without equalizer. Dyeing results are shown in Figures 7 and 8.

Figure 7. Dyeing with C.I. Acid Orange 33 in varying equalizer concentrations

Figure 8. Dyeing with C.I. Acid Violet 90 in varying equalizer concentrations


Colouring were made by choosing microwave

level 759 watts and 5 minutes duration. 1% dye, 1/50 liquor ratio, and 1 g/L equalizer were used for dyeing. Experiments were carried out at a pH ranging from 3 to 6 in the dyeing solution. Dyeing results are shown in Figures 9 and 10.

Figure 9. Dyeing with C.I. Acid Orange 33 in varying pH

Figure 10. Dyeing with C.I. Acid Violet 90 in varying pH

Dyeing was carried out with the pH=4.5, at microwave level of 759 watts in the 5 minute period by using 1g/L equalizer. The effect of dye concentration on dyeing was studied in the experiment. Dyeing results are shown in Figures 11 and 12.

Figure 11. Dyeing with C.I. Acid Orange 33 in varying dye concentrations

Figure 12. Dyeing with C.I. Acid Violet 90 in varying dye

concentrations

CONCLUSION

In the dyeings have been done at different

levels of microwave; Microwave power of 759 watts is sufficient. It creates abrage and solution losses at higher powers. This condition was observed in C.I. Acid Violet 90 for 10 minutes.

In the dyeings have been made in different

flotters; as the amount of float increased, the concentration of dyestuff on the flotte decreased, and the K/S values also decreased.

In the dyeings made without and with

equalizer; dyeing without equalizer are ineffective. Leveling agent concentrations can vary according to the dyes of the structure. Low concentrations are sufficient for readily soluble dyes.

In the dyeings at different pH; pH = 3 gave the

best results. When the pH is lowered, the dyeing speed is increasing. Under pH = 3, no dyeing work has been done since the fabric will begin to be damaged. Deep dyeing was obtained because the work was carried out at pH 3 at very high speed. The ideal pH range for dyeing is between 4.0 and 5.5. For C.I. Acid Orange 33, the K / S values between pH 4 and pH 5.5 at 450 nm are close to each other. For C.I.Acid Violet 90, the K / S values between pH 4 and pH 5.5 at 530 nm are very close to each other.

In the dyeing made in different staining

intensity;The increase of dyeing intensity is slow at low concentrations. The rate of dyeing is increased as increase dye concentration.


ACKNOWLEDGEMENTS

In studies and spectrophotometer measurements, we thank Aydın Örme A.Ş. who helped us.

REFERENCES 1Nunn, D,M. The Dyeing of Synthetic Polymer And Acetate Fibers, Universty of Bradford, DyersCompanyPublicationTrust, 358, England.,(1979). 2Baser, İ., “Tekstil Teknolojisi’’ Marmara Üniversitesi Yayınları,

Yayın No:634, İstanbul, Türkiye120-208(1998). 3Karahasan, N., Keskin, E.; ‘’Yün/Polyamid Karışımlarının Boyanması’’, Lisans Tezi, Marmara Üniversitesi Teknik Eğitim Fakültesi,İstanbul, Türkiye, 10-12(1998). 4Doyuran, A. “Sentetik Elyafın Mikrodalga Ortamında Boyanması’’,

Yüksek Lisans Tezi, Sakarya Üniversitesi, Fen Bilimleri Enstitüsü, Sakarya, Türkiye, 23-30(2010). 5Tarakçığlu, I.,Tekstil Boyacılığı, Cilt II. Ege Üniversitesi, 373, İzmir., 1974-3975

6Kim, S.S, Leem, S.G.,Ghim, H.D.,Kım, J.H.,Lyoo,W.S., Microwave Heat Dyeing of Polyester Fabric, Fiber and Polymers, 4,4, 204-209,(2003). 7Ujhelyiova, A.,Bolhova, E., Oravkinova, J., Tino, R., Marcincin, A., Dyes and Pigments, 2007, 72, 212-216, 8Gupta,B.,Plessier,C., Journal Of Applied Polymer Science, , 1999, 73, 2293-2297. 9Shibusawa, T.,Bull. Chem. Soc. Jpn., 1981, 54, 3, 909-912. 10Choi, T.S.,Shimizu, Y., Shirai, H., Hamada, K., Dyes and Pigments, 2001, 48, 217-226. 11Yiğit, E.A., Teker, M.; Polymers&Polymer Composites, Vol. 19, No. 8, 2011, 711-716. 12Lı, D., Sun, G., ColorationTechnology, 2006,122,194-200. 13Trotman, E.R.;Dyeing And ChemicalTechnology Of TextileFibres, 4th Ed. Charles Griffin&Co.Ltd., London, 1970. 14Needles, H.L.,Textile fibers, Dyes, Finishes And Processes, Noyels Publications, Usa, 1986. 15Bogdal, D.,Prociak, A., Microwave-Enhanced Polymer Chemistry And Technology, Blackwell Publishing, Usa, 2007. 16Kingston, H.,Haswell, J., Microwave-Enhanced Chemistry, Fundamentals, Sample Preparation And Applications. American Chemical Society: Washington, Dc, 1997.


Bentonite/Capric Acid Composite PCMs: Preparation,

Characterization and Latent Heat Thermal Energy Storage Characteristics

Ahmet SARI

Karadeniz Technical University, Department of Metallurgical and Material Engineering, 61080, Trabzon, Turkey

KFUPM, Centers of Research Excellence, Renewable Energy Research institute, 31261, Dhahran, KSA [email protected]

Keywords: Form-stable, Composite PCM, bentonite, capric acid, latent heat, thermal energy storage.

INTRODUCTION

In latent heat thermal energy storage (LHTES) systems, phase change material (PCM)s can store or release large amounts of latent heat via phase change in a constant or narrow temperature range. Organic solid-liquid PCMs have been generally preferred for heating and cooling applications because of some advantageous LHTES properties [1]. However, the requirement of an extra storage container to dispose the outflow problem occurred during phase change from solid to liquid limits their wide-range utilizations for LHTES purposes. This problem can be overcome by the holding of them by them into a porous building materials. In this sense, the incorporation of PCMs with porous and lightweight materials is simple, cost-effective, environment friendly and needed no solvent [2]. Various PCMs have been integrated with different porous building clays such as perlite [3], diatomite [4] and vermiculite [5]. Bentonite is consisted basically with clay minerals of the smectite (montmorillonite) group and some advantageous properties such as low cost, excellent absorption capacity, and direct usability traditional construction materials. These properties make it good candidate for the production of building composite PCMs for the LHTES purposes in buildings. In this regard, bentonite(BNT)/Capric acid(CAc) was prepared as building composite PCM (BCPCM) via vacuum impregnation method. The prepared BNT/CAc composite PCM was characterized structurally and morphologically by using FTIR and SEM techniques. The LHTES properties of the BCPCM before and after thermal cycling process were also measured. Moreover, the thermal durability of the composite PCM were determined by using TG analysis methods.

EXPERIMENTAL SECTION

Bentonite (BNT) used as supporting matrix is Turkish origin (in Reşadiye region of Tokat/Turkey). The dried

BNT is mainly composed of 61.82wt% SiO2, 17.3 wt%Al2O3, 4.5wt%CaO, 3wt%Fe2O3, 2.7wt%Na2O,

2.1wt%MgO and other metal oxides. The CAc was obtained from Sigma-Aldrich company (Germany). The BNT/CAc composites were produced using vacuum impregnation method. During impregnation runs, the amount of the CAc was changed from 10 to 50wt%. The holding amount of PCM was controlled simultaneously with leakage test. Based on the leakage tests applied for each combination, the maximum mass fraction of CAc into the BNT was 40wt%. The morphological investigations were carried out by using a SEM instrument with LEO 440 model. The chemical characterization was made by using a FT-IR spectrophotometer with JASCO 430 model. The TES properties and thermal degradation temperatures were measured by a DSC instrument with Perkin Elmer JADE model and a TG instrument with Perkin–Elmer TGA7 model. The LHTES reliability of the prepared BCPCM was determined by using a thermal cycler with BIOER TC-25/H model.


3.1. Microstructure characterization of prepared BNT/CAc composite PCM The morphological investigations showed that BNT before impregnation process, it is consisted with haphazard shaped-coarse particles dispersed arbitrarily through the surface. The spaces among the particle layers enable the holding CAc molecules and thus preventing their exudation from the surface of matrix. Moreover, after impregnation process, the spaces between the micro particles of BNT completely were occupied separately with CAc used as PCM. Moreover, the surface tension and capillary forces between the CAc molecules and inter layers of BNT make whole matrix structurally durable against the exudation problem of PCMs above their melting temperatures.


3.2. Chemical characterization of prepared BNT/CAc composite PCM As seen from the FTIR spectrum of BNT in Fig. 1 analysis, the main peaks shown between 3235 cm-1 and 3617 cm-1 and around 1637 cm-1 are attributed to the stretching vibration and bending vibration regarding with water in the structures of BNT. It has also other characteristic bands such as Si-antisymmetric vibration and bending vibrations at 1039 cm-1 and 460 cm-1 and 1045 cm-1 and 463 cm-1, respectively. On the other hand, in the spectrum of the BNT/CAc, the main characteristic bands showed only little shifts, which were due to the physical interactions. In addition to these results, non-observation of any new absorption peak in the spectrum of the composites confirmed the chemical inertness property of BNT against CAc.

Fig. 1. FT-IR spectra of the BNT and prepared BNT/CAc composite PCM 3.3. LHTES properties of prepared BNT/CAc composite PCM As seen the DSC curve given in Fig. 2, the BNT/CAc composite PCM shows a melting phase change at 30.07°C and solidification phase change at 26.16°C. These values are suitable for heating and cooling applications in buildings depending on the climatic conditions. On the other hand, by comparing the phase change temperatures of the pure CAc, it can be observed little decreases in case of prepared BNT/CAc composite PCM, which are due to weakly attractive interactions among the components of the composite PCM.

Fig. 2. DSC curves of the prepared BNT/CAc composite PCM.

On the other, the prepared BNT/CAc composite PCM has a melting and solidification enthalpy as 74.08 J/g and -71.12 J/g, respectively. These properties also make it promising composite for solar passive LHTES purposes in buildings. Additionally, by dividing the measured enthalpy value for the melting transition to the corresponding value of pure PCM the theoretical holding ratio of PCM by BNT was calculated as 38.9 wt% which is close to real impregnation mass fractions of 40wt%. However, lower real mass fraction could be owing to the non-free of phase transition of the PCM hold between inner layers of BNT. 3.4. LHTES dependability and chemical stability of the prepared BNT/CAc composite PCM A PCM should be dependable in term of its LHTES properties after long-term use. For this purpose, the LHTES dependability of the prepared BNT/CAc composite PCM was determined after repeated heating/cooling cycles for 1000 times. It is possible to observe very little amount of decrease in its melting and solidification temperature as 0.76 and 4.27°C, respectively. Moreover, after thermal cycling, the corresponding enthalpy values of the BNT/CAc composite PCM were reduced as little as 6.5% and 5.32% for freezing period, respectively. However, it can be concluded that the prepared BNT/CAc composite PCM has good LHTES dependability. On the other hand, a composite PCM should be stable chemically after thermal cycling treatment. As clearly perceived from the FT-IR spectrums in Fig. 4, the profile and wavenumbers of the characteristic absorption bands of the prepared BNT/CAc composite PCM were kept without change after thermal cycling. These results mean that the prepared BNT/CAc composite PCM has good chemical stability. 3.5. Thermal resistance of the prepared BNT/CAc composite PCM A freshly prepared BNT/CAc composite PCM should show good thermal resistance against high temperature. In this regard, the TG analysis of CAc and the prepared BNT/CAc composite PCM was carried out in the temperature range of 50-800°C. As seen from Fig. 5, about 3%-part of total weight of pure CAc loses by evaporation at 90°C and its weight loss actions was ended at about 220°C.


Fig. 3. TG curves of pure CA and produced F-SPCMs.

As also seen Fig. 3, CAc were evaporated in the range of 130-225°C, which is corresponded to the percentages of weight loss of 38.5wt%. These results indicated that the degradation temperatures of the CAc hold into composite are extremely over its phase change temperatures. Thus, it can be concluded that the prepared BNT/CAc composite PCM have high thermal resistant and thus good thermal stability.

CONCLUSION

This study is focused on preparation, characterization and investigation of LHTES properties of BNT/CAc composite PCM. According to the leakage test, the maximum absorption ratio of CAc was found to be 40wt%. The FT-IR and SEM results exposed the presence of good physical compatibility. The DSC measurements indicated that the prepared BNT/CA

composite PCM has suitable phase change temperature and good latent heat capacity for solar heating and cooling applications for buildings envelopes depending on climatic conditions. Thermal cycling test showed that the prepared BNT/CAc composite PCM has good LHTES dependability and chemical stability. TG analysis exhibited that the prepared BNT/CAc composite PCM had considerably high thermal resistance. By taking account of all results, it can be also deduced that the prepared BNT/CAc composite PCM can be considered as promising construction materials for building envelops as thermal insulating/coatings or, plaster boarding material.

REFERENCES

[1] Pomianowski M, Heiselberg P, Zhang Y. Review of thermal energy storage technologies based on PCM application in buildings. Energy Build 2013;67:56-69. [2] Memon SA, Lo TY, Cui H, Barbhuiya S. Preparation, characterization and thermal properties of dodecanol/cement as novel form-stable composite phase change material. Energy Build, 2013;66:697-705. [3] Jiao C, Ji B, Fang D. Preparation and properties of lauricacid–

stearicacid/expanded perlite composite as phase change materials for thermal energystorage. Mater Lett 2012; 67:352–354. [4] M. Li, H. Kao, Z. Wu, J. Tan, Study on preparation and thermal property of binary fatty acid and the binary fatty acids/diatomite composite phase change materials. Appl Energy 88;2011:1606-1612. [5] Karaipekli A, Sarı A. Capric–myristic acid/vermiculite composite as form stable phase change material for thermal energy storage. Sol. Energy 83;2009:323-332.


Latent Heat Thermal Energy Storage by Using Phase Change

Materials

Ahmet SARI

Karadeniz Technical University, Department of Metallurgical and Material Engineering, 61080, Trabzon, Turkey KFUPM, Centers of Research Excellence, Renewable Energy Research institute, 31261, Dhahran, KSA

[email protected]

Keywords: Latent heat, thermal energy, energy storage, phase change material

INTRODUCTION

The continuous increase in the level of greenhouse gas emissions and the climb in fuel prices are the main driving forces behind efforts to more effectively utilize various sources of renewable energy. In many parts of the world, direct solar radiation is considered to be one of the most prospective sources of energy. The scientists all over the world are in search of new and renewable energy sources. One of the options is to develop energy storage devices, which are as important as developing new sources of energy. The storage of energy in suitable forms, which can conventionally be converted into the required form, is a present day challenge to the technologists. Energy storage not only reduces the mismatch between supply and demand but also improves the performance and reliability of energy systems and plays an important role in conserving the energy [1]. It leads to saving of premium fuels and makes the system more cost effective by reducing the wastage of energy and capital cost. For example, storage would improve the performance of a power generation plant by load leveling and higher efficiency would lead to energy conservation and lesser generation cost. One of prospective techniques of storing thermal energy is the application of phase change materials (PCMs). The utilization of phase change materials (PCMs) in active and passive solar buildings has been subject to considerable interest since the first reported application in the 1940s. The appeal of PCMs is that they can store heat energy in a latent, as well as sensible fashion, leading to greater latent heat thermal energy storage (LHTES) capacity per unit volume than that of conventional materials [2]. As shown in Fig. 1, while the ambient temperature rises, the chemical bonds within the PCM break up as the material changes phase from solid to liquid (as is the case for solid-liquid PCMs which are of particular interest here). While the environment cools down, the PCM will return to solid phase and reject the heat it had absorbed.

Fig. 1. Working principle of a phase change material (PCM) (https://www.google.com.tr/search?q=phase+change+material). 2. Latent heat thermal energy storage (LHTES) PCMs are ‘‘latent’’ heat storage materials. They use

chemical bonds to store and release the heat. The thermal energy transfer occurs when a material changes from solid to liquid, or liquid to solid. This is called a change in state or phase. PCMs used for LHTES applications, having melting temperature between about -50 and 500ºC (low-temperature applications:<30ºC; middle-temperature applications:30-100ºC and high temperature applications:>100ºC), were used/recommended for thermal storage in conjunction with both passive storage and active solar LHTES for heating and cooling. A large number of PCMs are known to melt with a heat of fusion in the required range. However, for their employment as LHTES materials these materials must exhibit certain desirable thermodynamic, kinetic and chemical properties. Moreover, economic consideration and easy availability of these materials has to be kept in mind. The storage capacity of the LHTES system with a PCM medium [4] is given by the following equations:


Fig. 2. Classification of PCMs used for thermal energy storage [5].

3. Properties of PCMs The PCM to be used in the design of LHTES system should posses desirable thermophysical, kinetic and chemical properties, which are recommended as follows [4]. 3.1.Thermophysical properties (i) Melting temperature in the desired operating temperature range. (ii) High latent heat of fusion per unit volume so that the required volume of the container to store a given amount of energy is less. (iii) High specific heat to provide additional significant sensible heat storage. (iv) High thermal conductivity of both solid and liquid phases to assist the charging and discharging energy of the storage system. (v) Small volume change on phase transformation and small vapor pressure at operating temperature to reduce the containment problem. (vi) Congruent melting of the phase change material for a constant storage capacity of the material with each freezing/melting cycle. 3.2. Kinetic properties (i) High nucleation rate to avoid super cooling of the liquid phase. (ii) High rate of crystal growth, so that the system can meet demand of heat recovery from the storage system. 3.3. Chemical properties (i) Complete reversible freeze/melt cycle. (ii) No degradation after a large number of freeze/melt cycle.

(iii) No corrosiveness to the construction materials. (iv) Non-toxic, non-flammable and non-explosive material for safety. 3.4. Economic properties (i) Cost effective (ii)Commercially available 3.5. Environmental properties (i) Low environmental impact or non-polluting during service life (ii) Having recycling potential 4. Classification of PCMs PCMs are categorized as Organic, Inorganic and Eutectic materials. 4.1. Organic PCMs Organic materials are further described as paraffin and non-paraffins. Organic materials include congruent melting, self-nucleation and usually non-corrosiveness to the container material. Commonly used organic PCMs are listed in Table 1. 4.2. Inorganic PCMs Inorganic materials are further classified as salt hydrate and metallics. Inorganic compounds have a high latent heat per unit mass and volumes are low in cost in comparison to organic compounds and are non-flammable. However they suffer from decomposition and supercooling which further can affect their phase change properties. The commonly used inorganic PCMs are listed in Table 1. 4.3. Eutectics An eutectic is a minimum-melting composition of two or more components, each of which melts and freeze congruently forming a mixture of the component crystals. The commonly used eutectic PCMs are listed in Table 1. Table. 1. Common PCMs sued for LHTES applications.


5. Common utility areas of PCMs

The PCM can be used for different areas for LHTES as given below [6]:

5.1. Air Condition

Until very recently, PCMs were not reliable enough to be used in air condition. We have developed PCM with almost infinite life and good performance in the human comfort range of 18ºC to 29ºC and further for electronic comfort at higher temperature [7].

5.2. Transportation

Transportation of perishable foods, temperature sensitive pharmaceuticals, sundry electronics (like ignition transformers) and chemicals (explosives) require refrigerated trucks. Such refrigerated trucks are prohibitively expensive to operate as they use Diesel as a source of energy. Cost of diesel-generated energy is 6 times higher as compared to conventional electricity cost. Thus, Phase Change Material store energy using a cheap source of power and release it when that cheap source of power is not available [8].

5.3. Automobiles

PCM is already used today in a latent heat battery offered by BMW as optional equipment in its 5 series. The principle is quite simple, the storage material is connected to the radiator and stores excess heat when the motor runs at operating temperature. This heat is then available at the next cold start to heat up the motor quickly (better gas mileage) and for the interior (driving comfort). Due to the latent heat battery’s excellent

insulation, it can maintain the energy for 2 days at an outside temperature of – 20°C. As an extension to this application, PCM can also be used in tail-pipes (exhaust) of vehicles. This will maintain the catalytic converter at its design temperature, reducing excessive Hydro-carbon emissions during vehicle start up [9].

5.4. House heating, warm water

Solar energy is not available at all times, and therefore solar installations require an intermediary storage of the energy for heating or warm water. PCM based system will offer the following benefits over a conventional system: Low volume in comparison to water storage systems and a higher efficiency due to a lower temperature difference between loading and discharging of the energy. LHTES can also be implemented in conventional heating systems. PCM based solar water heater will also give a better controlled water temperature [10,11].

5.5. Construction materials

The atmosphere in a room is found comfortable if it varies little in the course of the day. For this reason, homes with very thick walls are found especially comfortable: cool in the summer and warm in the winter. To achieve this comfort in less massive constructions, one can implement materials containing PCM and thus demonstrating the same properties as thick walls. By absorbing heat at the peaks (e.g. during sunshine) and delayed release in the night, in most cases one can even do without air conditioning [12,13].

5.6. Cooking

The transportation of warm meals requires a heat source; otherwise it will not meet the quality standards set by the consumers. An electric heating source cannot always be implemented, in such cases PCM offer an ideal, self-regulating heating element. The melting point of the PCM depends upon the temperature at which the food should be kept. 60°C– 70°C are optimal so that the food does not continue to cook but is hot enough to eat [13].

5.7. Electronics

Electronic circuitry is extremely sensitive to over-heating, negatively influencing both lifetime and reliability of the parts. To date, metal fins are used for heat sinking improving their cooling capacity with additional fans. The sinking of heat peaks using PCM is absolutely reliable since no motor or temperature measurements are required. The PCM regenerates itself between peaks by emitting the heat with cooling fins. The advantage is a smaller cooling system with a very high reliability [14].

5.8. Green Houses

It is important to maintain temperatures in a small range to enable plants cultivated in a green house to flourish. However, due to large temperature swings in daytime and nighttime temperatures, most green houses need air-conditioning and/or heating. PCM installed in floor of such green houses will eliminate or reduce the dependence on air-conditioning/heating [15].

5.9. Textiles

In applications of PCM technology to garments and home furnishing products, PCM microcapsules are incorporated into acrylic fibers or polyurethane foams or are embedded into coating compounds and topically applied to fabrics or foams. A variety of outdoor apparel products with PCM microcapsules, such as ski wear,


hunting clothing, boots, gloves, and ear warmers. Nonetheless, there are few reports on the formulation of

PCM microcapsules and finishing onto textile fabrics or on the evaluation of their characteristics, including their thermal properties and durability [16].

CONCLUSION

The storage of energy in suitable forms, which can conventionally be converted into the required form, is a present day challenge to the technologists. Energy storage not only reduces the mismatch between supply and demand but also improves the performance and reliability of energy systems and plays an important role in conserving the energy. The utilization of phase change materials (PCMs) in active and passive latent heat thermal energy storage (LHTES) applications been subject to considerable interest since the first reported application in the 1940s. The appeal of PCMs is that they can store heat energy in a latent, as well as sensible fashion, leading to greater LHTES capacity per unit volume than that of conventional materials. While the ambient temperature rises, the chemical bonds within the PCM break up as the material changes phase from solid to liquid (as is the case for solid-liquid PCMs which are of particular interest here). While the environment cools down, the PCM will return to solid phase and reject the heat it had absorbed. In the this study, definition of LHTES concept, PCMs commonly used for LHTES applications, the selection criteria (thermo physical, kinetic and thermodynamic), classification, kinds and commonly utility areas of the PCMs were systematically presented. In this regard, this work is aimed to create awareness on the LHTES by

using PCMs as characterized as organic, inorganic and their eutectic chemicals.

REFERENCES

[1] R. Parameshwarana, S. Kalaiselvamb, S. Harikrishnanb, Renewable and Sustainable Energy Reviews 16 (2012) 2394– 2433. [2] Atul Sharma, V.V. Tyagi, C.R. Chen, D. Buddhi, Renewable and Sustainable Energy Reviews 13 (2009) 318–345. [3] (https://www.google.com.tr/search?q=phase+change+material). [4] Vineet Veer Tyagi, D. Buddhi, PCM Renewable and Sustainable Energy Reviews, 11 (2007) 1146–1166. [5] V. V. Tyagi, D. Buddhi, R. Kothari, S. K. Tyagi, Energy and Buildings, 51 (2012) 248-254. [6] (http://www.teappcm.com/applications.htm) [7] Parameshwaran R, Harikrishnan S, Kalaiselvam S. Energy and Buildings 2010;42:1353–60. [8] Takahiro Nomura, , Noriyuki Okinaka, Tomohiro Akiyama, Resources, Conservation and Recycling, 54, 2010, 1000–1006. [9] A. Jamekhorshid, S. M. Sadrameli, World Academy of Science, Engineering and Technology, International Journal of Chemical, Molecular, Nuclear, Materials and Metallurgical Engineering, 6, No:1, 2012. [10] Atul Sharma, C. R. Chen, International Review of Chemical Engineering (I.RE.CH.E.), Vol. 1, N. 4 July 2009 [11] A. K. Bhargava, Applied Energy 14 (1983) 197–209. [12] Parfait Tatsidjodoung, Nolwenn Le Pierres, Lingai Luo, Renewable and Sustainable Energy Reviews 18 (2013) 327–349. [13] Abhishek Saxena, Shalini Lath, Vieet Tirth, MIT International Journal of Mechanical Engineering, 3, 2013, 91–95. [14] Ravi Kandasamy, Xiang-Qi Wang, Arun S. Mujumdar, Applied Thermal Engineering, 28, 2008, 1047–1057. [15] Atyah Najjar, Afif Hasan, Special Issue 3rd International Conference on Thermal Engineering: Theory and Applications 49, 2008, 3338–3342. [16] Younsook Shin, Dong-Il Yoo, Kyunghee Son, Journal of Applied Polymer Science, 96, 2005, 2005–2010.


Microencapsulated Phase Change Materials (MEPCMs) for Latent

Heat Thermal Energy Storage

Ahmet SARI

Karadeniz Technical University, Department of Metallurgical and Material Engineering, 61080, Trabzon, Turkey KFUPM, Centers of Research Excellence, Renewable Energy Research institute, 31261, Dhahran, KSA

[email protected]

Keywords: Microencapsulation, phase change material, latent heat, thermal energy storage.

INTRODUCTION

Thermal energy storage can be accomplished either using sensible heat storage and/or using the latent heat storage. The principle of using the phase change materials (PCMs) is simple, as the heat supplies, the material changes its phase from solid to liquid and vice versa at constant temperature until it completely converts into solid. Similarly, when heat is released, the material changes phase from liquid to solid. Again at constant temperature until it solidifies completely [1,2]. The microencapsulation technique has been widely used in the pharmaceutical and chemical engineering fields. In recent years this technology has reached the field of phase PCMs in order to improve their behavior. Microencapsulated PCMs (MEPCM) are composed of PCM core and inorganic or polymeric shells to maintain the shape, prevent PCM leakage, and increase specific heat transfer area during the phase change process [3-5]. Encapsulation can also reduce the reactivity of PCMs with outside environment and enable the core material to withstand ultra-frequent changes in volume of the thermal storage material during its phase transition. The potential of MEPCMs for thermal storage greatly depends on their thermal performance, which is usually influenced by several factors, including average size, expansion during the phase change process, and the shell’s chemical composition [6-11]. There are many kinds of MEPCMs which can potentially be used for the secondary loop purpose. However, before it can be used, one kind of MEPCMs should generally meet several requirements for both core and shell materials, which include the follows: (1) core material: suitable temperature range, large latent heat, reasonable thermal conductivity, low volume change, low reactivity, and so on; (2) shell material: good sealing tightness, endurance, good elastic strength, water and fire resistance, and so on. It is actually almost impossible to find a MEPCM which can meet all the above requirements. However, the surface area, mechanical strength, and thermal stability of most MEPCMs prepared by these methods are inadequate for many applications. In addition, the important issues

associated with the uses of these methods are complex, multi-step synthesis and their undesirable residues such as formaldehyde for commonly used aminoplast resins used as shell materials. 2. Fabrication of MEPCMs MEPCMs are small particles of material coated by another material, the second material forming a thin film over the first one, isolating and protecting from the environment. Size range of microcapsules is quite wide, with diameter slurry between 2µm and 2000µm and the core constitutes between 20 and 95% of the total mass. There are many different fabrication techniques for microcapsules, and the choice is made depending on the characteristics of the active material to be encapsulated and the type of polymeric material used as shell [2]. In a first stage, a dispersion is formed with the active material. In a second stage, this dispersion is transformed and finally, stabilization and solidification techniques are applied to the shells before separation (Fig. 1).

Fig. 1. The production stages of a MEPCM [12].


There are several methods that can be used to produce MEPCMs. Depending on the nature of the process, there are physical, physical–chemical, and chemical processes [2]: Physical methods: i. pan coating, ii. air-suspension coating, iii. centrifugal extrusion, iv. vibrational nozzle, v. spray drying, vi. solvent evaporation. Physic-chemical methods: i. Ionic gelation, ii. coacervation, iii. sol-gel. Chemical methods: i. interfacial polymerization, ii. suspension polymerization, iii. emulsion polymerization (General aspect of the chemical synthesis method used in the fabrication of MEPCMs is shown in Fig. 2.

Fig. 2. A simple method to make MPCM [13]. 3. Recent studies on MEPCMs with organic shell Onder et al. [14] were also encapsulated three types of paraffin waxes, namely n-hexadecane, n-octadecane and n-nonadecane by complex coacervation method. Sarier and Onder [15] worked on the thermal insulation capability of PEG-containing polyurethane foams. Sarı

et al. [16] studied the microencapsulated n-octacosane as phase change material for thermal energy storage. This study deals with preparation and characterization of polymethylmetracrylate (PMMA. Zhang and Niu [17] presented the experimental investigation of effects of super-cooling on microencapsulated phase-change material (MPCM) slurry for thermal storage capacities. Fang et al. [18] studied the n-tetradecane was encapsulated urea and formaldehyde via in-situ polymerization method. Sanchez et al. [19] developed a cheap and technically feasible process for the encapsulation of different phase change materials with a polymer shell of polystyrene by suspension polymerization. Sánchez at al. [20] successfully encapsulated different non-polar PCMs such as PRSs paraffin wax, tetradecane, RubithermsRT27, RubithermsRT20, and nonadecane with a polymer shell of polystyrene by suspension polymerization method. n-Pentadecane was encapsulated into the

methylmethacrylate (MMA) byTaguchietal. [21] via the suspension polymerization method. You et al. [22] added MEPCMs(n-octadecane) withstyrene– divinybenzene copolymer shell in foaming system directly and PU foams with increased enthalpy were produced. In another study they investigated the influence of different parameters on microencapsulation of n-octadecane with styrene–divinybenzene copolymer shell [23]. Li etal. [24] encapsulated n-octadecane with different copolymer shells by suspension polymerization. Sarı et al. carried out a number of

studies in the preparation of microencapsulated PCM by emulsion polymerization using docosane [25], n-octacosane [26], n-hexadecane [27,28], and n-heptadecane [29] as core material and PMMA resin as shell materials. Alay et al. [30] produced microencapsulated n-hexadecane with poly(butylacrylate)(PBA) by using allylmethacrylate, ethylene glycol dimethacrylate, and glycidyl methacrylate as cross- linkers.

CONCLUSIONS

Microencapsulation technology is used to prepare MEPCM, as a new kind of LHTES composite material. The selection of these microencapsulation techniques is highly dependent on the specifications of microcapsules; the required capsule size, materials of the core and shell, thickness of the microcapsule shell, thermal and mechanical properties of the capsule, etc. The most common methods described in the literature for MEPCM production are interfacial polymerization, suspension polymerization, coacervation, emulsion polymerization, and spray drying. This paper presents a review on microencapsulation methods and thermal characteristics of MEPCMs. However, there is no complete overview of its utilization in thermal energy storage systems, and the information is widely spread in the literature. In this paper, a comprehensive review has been carried out for MEPCMs, which are used for the LHTES applications.

REFERENCES

[1] P. Zhang, Z.W. Ma, R.Z. Wang, Renewable and Sustainable Energy Reviews 14 (2010) 598–614. [2] A. Jamekhorshid, S.M. Sadrameli, M. Farid, Renewable and Sustainable Energy Reviews 31 (2014) 531–542. [3] C.Y. Zhao and G.H. Zhang, Renew. Sustain. Energy Rev., 15, 3813 (2011). [4] V.V. Tyagi, S.C. Kaushik, S.K. Tyagi, and T. Akiyam, Renew. Sustain. Energy Rev., 15, 1373 (2011). [5] Y. Fang, S. Kuang, X. Gao, and Z. Zhang. Energy Convers. Manage., 49, 3704 (2008). [6] K. Hong and S. Park, Mater. Sci. Eng. A, 272, 418 (1999). [7] X.X. Zhang, Y.F. Fan, X.M. Tao, and K.L. Yick, Mater. Chem. Phys., 88, 300 (2004). [8] Y.S. Shin, D. Yoo, and K. Son, J. Appl. Polym. Sci., 96, 2005 (2005).


[9] 12. J.S. Cho, A. Kwon, and C.G. Cho, Colloid Polym. Sci., 280,260 (2002). [10] M.N.A. Hawlader, M.S. Uddin, and M. Khin, Appl. Energy, 74, 195 (2003). [11] Y. Rong, H.Z. Chen, D.C. Wei, J.Z. Sun, and M. Wang, Colloid. Surf. A, 242, 17 (2004). [12] Schimidt, M. BASF Micronal, Energiforum, Denmark, 2008. [13] Ai YF, Jin Y, Sun J, Wei DQ. e-Polymers 2007;1–9,98. [14] Onder E, Sarier N, Cimen E. Thermochim. Acta 2008;467:63–72. [15] Sarier N, Onder E. Thermochim.Acta 2008;475:15–21. [16] Sarı A, Alkan C, Ali K, Uzun O. Solar Energy 2009;83:1757–63. [17] Zhang S, Niu J. Solar Energy Materials & Solar Cells 2010;94(6):1038–48. [18] Fang G, Li H, Yang F, Liu X, Wu S. Chemical Engineering Journal 2009;153:217–21. [19] Sanchez L, Sanchez P, de Lucas A, Carmona M, Rodriguez JF. Colloid and Polymer Science 2007;285:1377–85.

[20] Sánchez L, Sánchez P,de Lucas A,Carmona M, Rodríguez J. Colloid Polym Sci 2007;285:1377–85. [21] Taguchi Y, Yokoyama H, Kado H, Tanaka M. Colloids SurfA:Physicochem Eng Asp 2007; 301:41–7. [22] You M, Zhang X, Wang J, Wang X. J Mater Sci 2009;44:3141–7. [23] You M, Wang X, Zhang X, Zhang L, Wang J. J Polym Res 2011;18:49–58. [24] Li W,Song G,Tang G, Chu X, et al., C. Energy 2011;36:785–91. [25] Alkan C, Sarı A, Karaipekli A, Uzun O. Sol Energy Mater Sol

Cells 2009;93:143–7. [26] Sarı A, Alkan C, Karaipekli A, Uzun O. Sol Energy 2009;83: 1757–1763. [27] Alay S, Göde F, Alkan C. Fibers Polym 2010;11:1089–93. [28] Alay S, Alkan C, Göde F. Thermochim Acta 2011;518:1–8. [29] Sarı A, Alkan C, Karaipekli A. Appl Energy2010;87:1529–34. [30] Alay S, Göde F, Alkan C. J Appl Polym Sci 2011;120:2821–9.


Antioxidant Activity of Caffeic Acid Isolated from Origanum bilgeri P.H. Davis

Ramazan ERENLER*1 and Gulacti TOPCU2

1Department of Chemistry, Faculty of Art and Science, Gaziosmanpasa University, TR-60240, Tokat, Turkey 2Department of Pharmacognosy and Phytochemistry, Faculty of Pharmacy, Bezmialem Vakif University, 34093

Istanbul, Turkey


Keywords:caffeic acid, Origanum bilgeri, antioxidant

INTRODUCTION

Origanum genus belongs to the Lamiaceae

family. It has 23 species and six hybrids in Turkey flora, 14 of which are endemic.1 Because of the wide range of application in food, cosmetic and medicinal industries, Origanum is cultivated in several European, Asian and African countries.2 Origanum species have been consumed as a folk medicine for treatment of sickness such as muscle pains, headache, rheumatism, diarrhea, asthma as herbal tea.3 Many works were executed about Origanum species to display the chemical composition of essential oil which has been applied in flavouring of various foods, particularly soups, meat, and bitters.4

Antioxidants play a significant function in eliminating free radicals, quenching singlet oxygen, disintegrating peroxides, donating hydrogen and chelating metal ion. Therefore antioxidants decrease DNA damage, reduce lipid peroxidation and inhibit cell proliferations.5 Antioxidants are frequently added to foods to prevent the radical chain reactions. However, synthetic antioxidants are suspected to have some toxic effects and possible carcinogens.6 Hence, there has been a considerable growing trend in usage of natural antioxidants over synthetic compounds.

The aerial part of O. bilgeri was extracted with water then; liquid part was partitioned with ethyl acetate. The caffeic acid was isolated from ethyl acetate extract by chromatographic techniques and its structure was elucidated by spectroscopic method such as 1D-NMR, 2D-NMR and LC-TOF/MS. Caffeic acid revealed the excellent ABTS+• scavenging and reducing power activities. It exhibited moderate DPPH• scavenging effect.


In this work caffeic acid was isolated from the ethyl acetate extract of O. bilgeri. The ethyl acetate extract was subjected to column chromatography to yield the fractions that applied to semi-preperative HPLC to isolate the pure caffeic acid. The molecular formula of caffeic acid was determined as C9H7O4 by LC-TOF/MS (m/z 179.0355 [M-H]-) (calcd. 179.0344). 13C spectrum revealing the presence of five methines, three quaternary carbons and one carbonyl carbon suited with the structure. Caffeic acid is well known natural product existing in many plant kingdoms7 (Fig. 1).

Fig. 1. Structure of caffeic acid

The antioxidant activities of caffeic acid were carried out using different antioxidant assays such as 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging and reducing power. Caffeic acid revealed the outstanding ABTS+• (Fig. 2) and reducing power activities whereas it exhibited the mild DPPH• activity (Fig. 3).


Fig. 2. ABTS cation radical scavenging activity

ABTS•+ assay based on the decreasing the ABTS radical cation, a blue/green chromophore with absorption at 737 nm, in comparison to that of BHA, BHT and trolox.8

Fig. 3. DPPH free radical scavenging activity

The mechanism of DPPH• scavenging activity is based on the hydrogen or electron releasing capability of antioxidant molecules to DPPH• molecules to form the non radical DPPH-H and the measurement of the reducing ability of antioxidants. During the reduction process, purple DPPH• changes to a colorless diphenyl picrylhydrazine and remaining DPPH• exhibiting the maximum absorption at 517 nm is measured.9 Reduction of Fe+3 to Fe+2 is determined by measuring the absorbance of Perl’s Prussian blue complex.

10 The reduction capacity of caffeic acid exhibited that it had a significant antioxidant potential.

CONCLUSION

Origanum bilgeri, important aromatic and medicinal plant has a potential to be used in natural antioxidant. Besides essential oils which intensively studied, secondary metabolites of this species should be presented and biological activities should be investigated.

ACKNOWLEDGEMENTS

The authors thank to the Scientific and Technological Research Council of Turkey (TUBITAK, No: 113Z195) for financial support.

REFERENCES

1Davis, P. H. Flora of Turkey and the East Aegean Islands; Edinburgh University Press: England, 1982; Vol. 7. 2Ozkan, A.; Erdogan, A. Turk J Biol 2011, 35, 735-742. 3Jun, W. J.; Han, B. K.; Yu, K. W.; Kim, M. S.; Chang, I. S.; Kim, H. Y.; Cho, H. Y. Food Chem 2001, 75, 439-444. 4Busatta, C.; Vidal, R. S.; Popiolski, A. S.; Mossi, A. J.; Dariva, C.; Rodrigues, M. R. A.; Corazza, F. C.; Corazza, M. L.; Oliveira, J. V.; Cansian, R. L. Food Microbiol 2008, 25, 207-211. 5Yan, S. W.; Ramasamy, R.; Alitheen, N. B. M.; Rahmat, A. Int J Food Prop 2013, 16, 1231-1244. 6Senevirathne, M.; Kim, S. H.; Siriwardhana, N.; Ha, J. H.; Lee, K. W.; Jeon, Y. J. Food Sci Technol Int 2006, 12, 27-38. 7Durust, N.; Ozden, S.; Umur, E.; Durust, Y.; Kucukislamoglu, M. Turk J Chem 2001, 25, 93-97. 8Re, R.; Pellegrini, N.; Proteggente, A.; Pannala, A.; Yang, M.; Rice-Evans, C. Free Radical Bio Med 1999, 26, 1231-1237. 9Gulcin, I. Arch Toxicol 2012, 86, 345-391. 10Gulcin, I. Chemico-Biological Interactions 2009, 179, 71-80.


The Investigation of Dyeing Kinetics of Cotton Fibers With Reactive

Dye in TheMicrowave Media

Murat TEKER*, Hüseyin KARACA, Zeynep DOYURAN *Department of Chemistry, Faculty of Art and Science, Sakarya University, TR-54187, Sakarya, Turkey

[email protected]

Abstract In this study, the knowledge about the cotton fibers and reactive dyes was given and color measurement systems and color fastness are explained. The whole properties of reactive dyes are given in detail. All application methods used for dyeing of cotton fabric with reactive dye are investigated. In this study, dye ability of cotton fiber is investigated in different dye baths by using microwave. By this purpose dyeing experiments have been done in different dye baths (three different liquors to good ratio: 1/20, 1/50 and 1/100 and three different dye stuff concentration: %0.5, %1 and %2 of) and optimum dye bath conditions were obtained. Dye ability of fibers was determined by using color strength values (K/S). In order to examine the kinetics of dyeing, diffusion coefficients in all methods were calculated. The value of dyeing intensity that has maximum dye uptake was found as 0.5%. The dye uptake is increasing with increase of the level of microwave power. More over the dye uptake is increasing linearly with dyeing period.

Key words:cotton, microwave, reactive dye

INTRODUCTION

Cotton fiber is the oldest known types of fibers and today continues to be the most widely used type of fiber1. In the past, it is painted with plant-based dyes.Various staining methods have been developed after the initiation of theproduction of synthetic dyes2. Until the discovery of the first reactive dye Procions to disrupt the chemical structure of the cellulosic fibers in the severe reaction conditions were thought to be formed covalent bonds. The chemical reactions in cotton fiber due to the presence of functional groups with high reaction ability such as -NH2 , -OH , -SH ve –COOH were thought to be much easier. Therefore, IC Company began to be applied to wool reactive dyestuffs research in 1951. In 1953, Dr. Stephen was able to synthesize dyes containing 2,4-dichlorothreeazinylamine group. Chemist Ratte who worked for the same company to achieve the application of dyestuff and to investigate the staining mechanism. Ratte remembered that cyanuryl chloride solution in xylene had been used for the esterification of cellulose. Ratte found that dye molecules react very easily with cellulose at room temperature3. All color ranges of reactive dyes (color gamut) are available and the colors are very bright. First, it was not possible to achieve with bright colors and basic and azo dyes.One more advantage of reactive dyes is also staining at cold conditions. This class of dyes is a very short time developed because large energy savings can be achieved. Other dye producer companies began intensive work on this issue and discovered many

reactive groups different from dichlorothreeazinyl. These give a chemical reaction with the cellulose, but most of the reactivity (reaction ability) is less than the reactivity of the diklorotriazinil group. Except for a few of them many of them is being implemented in hot4,5. When the cotton soaked in water the cotton absorbs water in the ratio of its 70% of weight6. Interaction the cotton fiber with liquid ammonia and sodium hydroxide is caused to swell7,8,9. The etherification is formed by the reaction between cotton fiber and ethylene oxide8.Reactive dyes are highly water-soluble dyes and they have very good wash, rubbing and light fastness2,6. A dyestuff can have only one or more then one reactive groups. Such dyes having more then one reactive groups are called bifunctional reactive dyes. Coloring efficiency of such dyes are better than the monofunctional structure10. For reactive dyestuffs dye in cold the temperature is 20-40 °C. They enter reaction very easily with the fiber without raising the temperature and without increasing the alkaline addition because of their high reactivity. Dyeing temperature is between 60-80 °C for reactive dyestuffs stained in hot. As reaction capabilities are weak activity is provided by raising the temperature and increasing the addition of alkaline. Very uniform dyeings obtained in hot dyeing due to high tempereature anddye penetration is excellent6. 1 degree increase of the pH the reaction rate increases 9-10 times6,11. The addition of salt in reactive dyeing increases substantivity12,13. Many textile dyeing process includes initially the dye transition from the aqueous solution to the fiber surface. This event is adsorption. Then dye molecules


diffuse into the fiber. Depending on the internal structure of the fiber it would form as transition to between polymer molecules or to the gap. This diffusion step is the step that determines the rate of diffusion. Adsorption and then penetration of dye into the fiber materials are called absorption14,15. Dye diffusion of fiber depends on the pH, temperature and chemical auxiliaries used of the dyebath14. Adsorption is a reversible process. Dyes can be returned to the aquatic environment during washing the material. This is defined as the desorption. Apart from direct absorption dyeing of fibers can include two steps. First the dyestuff can be precipitated in fiber second a chemical reaction between the fiber and dyestuffs. These two methods are irreversible processes that lead to better wash fastness15. Examining the diffusion kinetically that is the slow step of staining and determination of dyeing kinetics was studied by many researchers. Dye diffusion into the fiber is compatible with Fick's law.

According to Fick's second law, the dye diffusion flux (mol / m2s) into the fibers per unit area is proportional to concentration gradient in this region (dc / dx, mol / mm) and diffusion coefficient (D, m2/s)15. Diffusion to be into a cylinder (or filaments) of infinite length that has radius r can be axplained by the Hill equation.

In equation, Mt the quantity of dyestuff on the fibers at time t, M∞ the quantity of dyestuff on the fiber

in equilibrium, D diffusion coefficient, r represents the radius of the fiber.qn shows the positive roots of zeroth order Bessel function16. In the case of (Dt/r2)<<1 it will reduce the equation as known Crank Equation17,18.

t versus (Mt/M∞) is plotted and then diffusion coefficients can be determined from obtained slope of the line17,18.According to the Kubelka-Munk theory, There is a linear relationship between the concentration of the dyestuff on a dyed textile material and K/S values. In this case the values of (K/S)t / (K/S)∞ can be written instead of the values of Mt/M∞

18,19.Kubelka-Munk equation the most important mathematical expression that has been developed to measure the color of the dyed textile material. For a material dyed the resulting graph is far from being linear by concentration plotted against reflectance at a specific wavelength. But the required linear relationship is established as instrumental with Kubelka-Munk equation20. Kubelka-Munk equation:

K/S is the scattering coefficient and It is directly related to the dye concentration. R is the reflectance of the fabric at the maximum absorption wavelength20,21.Microwaves are located between infrared and radio waves in the electromagnetic spectrum. They are electromagnetic waves have frequencies between 300 MHz and 300 GHz. The wavelength of the microwaves is between 1 mm and 1 m. The microwaves are the type of electromagnetic energy Characterized by electrical and magnetic fields perpendicular to each other and non-ionizing. It leads to movement of molecules or ions. It can be projected, transmitted, absorbed and its absorption leads to the heat absorbed in material production22. Microwave energy penetrates into the sample and generates the internal heat. Its temperature gradient is minimum, creates volumetric heating and allows selective heating in the mixtures. Being high of the distribution factor which is the ratio of the dielectric loss factor and the dielectric constant shows that the samples take the microwave energy and are easily influenced by microwave. The second effect is ionic conduction. Ionic conduction is migration of dissolved or vibrating ions with the effect of changing electric field. With ionic conduction, it will accelerate the warming of the solution23.

EXPERIMENTAL STUDIES

The knitted fabric made of 100% cotton was used in the experimental study.Na2SO4 as salt, Na2CO3 as soda and IyozolRed HE 3B (figure 1) as reactive dye were used.

Scheme1. IyozolRed HE 3B (C.I. ReaktiveRed 120) KUM-1225 model Kumtel brand microwave (1150 W of power) and ColorEye 7000 A model GretagMacbeth brand Spectrophotometer were used in the study. The staining was done in different power and time using microwave energy in the dyeing baths prepared as different liquor (1/10, 1/20, 1/50 and 1/100) and the different coloring intensity (0.1%, 0.5%, 1% and 2%). The staning was done with times as1 min, 2 min, 3 min, 4 min, 5 min, 10 min, 15 min, 20 min, 25 min and 30 min in order to identify the optimum dyeing time for


liquor ratio of 1/100 M-L and M levels. Then the time dependence of coloring was determined in microwave medium. The staining work depending on the level of microwave were done at the power of 95.5W, 460W, 759W, 977.5W, 1150W and 0.1%, 0.5%, 1%, 2% in the staining intensity. The liquor ratio was 1:50.Depending on the amount of salt in 1.0, 1.5 and 2.0 g / L salt made with staining work was achieved on optimum values such as time (5 minute), liquor (1/50), dye intensity (2%) and microwave power level (M). Depending on the amount of soda in 1.0, 1.5 and 2.0 g / L soda made with staining work was achieved on optimum values such as time (5 minute), liquor (1/50), dye intensity (2%) and microwave power level (M). Depending on the liquor ratio made with staining work was achieved in different luor ratios on optimum values such as time (5 minute), dye intensity (2%) and microwave power level (M).


Depending on the time, for the M-L and M levels the staining studies have been done between 1 and 30 minutes the increase is seen in the values of K/S by increasing the time and microwave level.After 5 minutes, this increase may be considered to remain constant. This increase occurs by reason of the increase in the concentration of the staining solution by the evaporation.

Scheme2. M-L and M-level time-dependent staining.

Highest peak value were obtained as 540 nm different microwave levels and staining intensity. It can be seen

from figure 6.1 that the diffusion of 0.1% IyozolRed HE 3B into the cotton fiber at low concentrations, and the increase of the microwave level cause the low level of K/S.By the increase of staining intensity the diffusion of IyozolRed HE3B dyestuff into the cotton fiber and the increase of the value of K/S have been high. It can be seen from figure 6.1 that the highest K/S peaks were obtained at M-H level in the 0.5%, 0.1%, 2%, 4% dyeing. The K/S value of IyozolRed HE3B dye is seen decrease at high temperature or high microwave level (H). The reason for this is the reverse shift of reaction equilibrium and a high dyeing temperature counteracts the dye reactions. Because normal dyeing temperature is around 600 - 800C.

Scheme 3. Dye intensity-peak K/S change

Scheme 4. The change of K/S by the amount of salt

In the study to investigation of the effect of the amount of salt to the K/S value:The highest peak value were taken at 540 nm. It can be seen from figure 4 that The value of K/S is increasing very fast until 10 g/L. After the 10 g/L the value of K/S change is effected slowly but biggest K/S value was taken at 20 g/L. Salt content of 10 g / L used is sufficient.

Scheme5. K/S change by Soda Quantity


Scheme6. K/S change by liquor ratio

In the study that was investigated the effect of soda amount to the K/S:It is seen from figure 5 that the highest peak value is given at 540 nm and at the 0.8 g/L soda amount. The increase of amount of soda over 1 g/L does not change the dye uptake. The increase of soda concentration causes the hydrolysis of dyestuff. Therefore, the required amount of soda in normal staining is added towards the end of the staining and so staining is done. The optimum soda concentration in the microwave dyeing were determined as 0.8 g/L. In the study that was investigated the effect of liquor ratio to the K/S: By increasing the liquor ratio K/S values were observed to decrease wherein the highest peak value of 540 nm in figure 6. It shows a decrease in staining intensity with the thinning of the media.

ACKNOWLEDGEMENTS

This study was supported by the BAPK. We thank to BAPK for support

REFERENCES 1Özcan, Y., “Tekstil Elyaf Ve Boyama Tekniği”,

İstanbul Üniversitesi Yayınları, İstanbul, 1978, 176-209, 482-491. 2Başer, İ.,İnan, Y., “Boyarmadde Kimyası”, Marmara

Teknik Eğitim Fk. Tekstil Eğitimi Bölümü, İstanbul

1990, 7-17, 47-126. 3Kurbanlı, R., Mirzaoğlu, R., “Boya Ve Tekstil Kimyası

Ve Teknolojisi”, S.Ü Yayınları, Konya 2004, 318-340.

4Akçakoca, E., P., Özgüney, A.,T., Atay, R., Dyes And Pigments, 2006, 71:214-218. 5Tarakçıoğlu, I., Tekstil Ve Teknik, Eylül 1990, 21-28.

6Serindağ, O., Halefoğlu, Y., “Tekstil Kimyası”, Ç.Ü.

Fen Edebiyat Fak. Kimya Bölümü, 2001,126-142. 7Lewın, M., Pearce, E. M., “Handbook Of Fiber

Chemistry”, New York, 1998, 1083. 8İçoğlu, H.,İ., Yüksek Lisans Tezi, Çukurova

Üniversitesi, Adana, 2006. 9Warwıcker, J. O., Jefrıes, R., Colbran, R. L., Robınson,

R. N., “No:93, Manchester, 1966. 10Utaç, E., , Yüksek Lisans Tezi, Gazi Üniversitesi, Ankara, 2006. 76 11

Duran, K., “Tekstilde Renk Ölçümü Ve Reçete

Çıkarma”, Ege Üniversitesi Tekstil Ve Konfeksiyon Araştırma Ve Uygulama Merkezi, 2001. 17, 45-63. 12

Yakartepe, Z., Ünal, A., Yakartepe, M., “Büyük

Tekstil Terbiye Ansiklopedisi, T.K.A.M 2005, 18, 147, 342. 13

Hunger, K., “Industrialdyes, Chemistry, Properties,

Applications”, Wiley-Vch, Verlag 14Ujhelyiova, A., Bolhova, E., Oravkınova, J., Tıno, R.,

Marcıncın, A., Dyesand Pigments, 2007, 72, 212-216, 15

Gupta,B., Plessıer,C., Journal Of Applied Polymer

Science, , 1999, 73, 2293-2297. 16

Shıbusawa, T.,Bull.Chem.Soc.Jpn.,1981, 54, 3, 909-912. 17

Choı, T.S., Shımızu, Y., Shıraı, H., Hamada, K.,

Dyesand Pigments, 2001, 48, 217-226. 18

Yiğit, E.A., Teker, M.; Polymers & Polymer

Composites, Vol. 19, No. 8, 2011, 711-716. 19

Lı, D., Sun, G., Coloration Technology, 2006,122,194-200. 20Trotman, E.R.;Dyeing And Chemical Technology Of Textile Fibres, 4th Ed. Charles Griffin & Co.Ltd., London, 1970. 21Needles, H.L.,Textilefibers, Dyes, Finishes And Processes, Noyels Publications, Usa, 1986. 22

Bogdal, D., Procıak, A., Microwave-Enhanced Polymer Chemistry And Technology, Blackwell Publishing, Usa, 2007. 23

Kıngston, H., Haswell, J., Microwave-Enhanced Chemistry, Fundamentals, Sample Preparation And Applications. American Chemical Society: Washington, Dc, 1997.


Synthesis of 2-Arylpyrroles by Suzuki-Miyaura Cross-Coupling

Reaction*

Yavuz DERİN

a, İbrahim Halil BAYDİLEK

a, Raşit Fikret YILMAZ

a, Büşra ALBAYRAK

a, Salih ÖKTENb, Ahmet TUTARa

aSakarya University, Faculty of Science and Art Faculty, Department of Chemistry, Serdivan, Sakarya, 54187, TURKEY

bKırıkkale University, Faculty of Education, Department of Primary Education, Yahşihan, Kırıkkale, 71450, TURKEY

[email protected]

Keywords: Arylpyrroles, Bromination, Cross-coupling reaction

INTRODUCTION

The pyrrole and its derivatives are interesting compounds because pyrrole rings are not only found in natural products, pharmaceuticals, new materials but also show good biological and pharmacological properties and the polimerization reactions of these compounds give polypyrroles which serve as conducting polymers [1,2]. These compounds are important precursors in the synthesis of 4,4-Difluoro- 4-bora- 3a,4a-diaza- s-indacene molecules (BODIPY) which are used in many areas such as fluorescent switches, supramolecular polymers, labelling reagents, chemosensors, photodynamic therapy, choromogenic probes,laser dyes, and sensitizers for solar cell applications. Photophysical and electrochemical features of BODIPY compounds are directly related to the groups attacted to this compound. One of best strategies to enhance the features mentioned above is to functionalize the pyrrole ring with different groups to obtain new BODIPY compounds [3,4,5]. Suzuki coupling reaction is one of the best ways to synthesis of poly-olefins, styrenes, and substituted biphenyls

The general scheme for the Suzuki reaction is shown below where a carbon-carbon single bond is formed by coupling an organoboron species (R1-B(OH)2 with a halide (R2-X) using a palladium catalyst and a base.

Proposed mechanism of Suzuki coupling reaction is as shown below [6].

Figure1. Mechanism of Suzuki Coupling reaction

EXPERIMENTAL

In this study, we describe synthesis of 2-arylpyrroles in two steps. In first step, synthesis of N-Boc-2-bromopyrrole was carried out by gradually adding 1,3-dibromo-5,5-dimethylhydantoin into pyrrole in the presence of AIBN at -78 °C then protection of


amine was performed with di-tert-butyldicarbonate and a catalytic amount of DMAP. In second step N-Boc-2-arylpyrroles were prepared from the reactions of N-Boc-2-bromopyrrole with five diferent arylboronic acids via palladium catalyzed Suzuki-Miyaura cross coupling reaction followed by deprotection to obtain 2-arylpyrroles. 1) Bromination of pyrrole

2) Suzuki Coupling reaction


Figure 2. 1H Chemical Shifts of the final products as ppm

Figure 3. 13C Chemical Shifts of the final products as ppm

CONCLUSION

2-Arylpyrroles were successifully synthesized and structures of the compounds were characterized by 1H, 13C-NMR spectroscopy.

ACKNOWLEDGEMENTS

This study is supported by the Scientific and Technological Council of Turkey (TÜBİTAK,

KBAG-114Z176) and the Scientific Research Projects Unit of Sakarya University (BAP- 2014-02- 04-010).

REFERENCES

1. Sternberg, E. D.; Dolphin, D.; Bruckner, C. Tetrahedron 1998, 54, 4151–4202. 2. Bellina F. and Rossi R. Tetrahedron 2006, 62, P. 7213-7256 3. Goud, T.V., Tutar, A., Biellmann, J.F. Tetrahedron, 2006, 62, 5084-5091. 4. Tutar, A., Erenler, R., Biellmann, J.F. J. Chem. Soc. Pak. 2013, 35 (4), 1197-1201. 5. Lee, P.H., Bull. Korean Chem. Soc. 2008, 29 (1), 261-264. 6. Amatore, C.; Jutand, A; Le Duc, G. Chemistry: A European Journal. 17 (8): 2492–2503.


Removal of C.I. Basic Blue 3 Dyestuff from Textile Waste Waters by Electrochemical Treatment

Emrah BULUT

Sakarya Üniversitesi Kimya Bölümü, 54187 Sakarya, Türkiye

*[email protected]

Keywords:Electrocoagulation, Textile waste water, Basic Blue 3, Aluminum electrode, pH, Current density

INTRODUCTION

Using different chemicals and dyestuffs for

better performance in textile industries makes textile wastewater highly polluting in naturel environment [1]. Textile industry waste waters are carcinogenic, toxic and mutagenic for various fish and microbiological species due to high levels of chemical oxygen demand, dissolved solids, highly fluctuating pH, and poor biological degradation [2, 3]. Some compounds found in textile waste water react with light and disturb the ecosystem [4, 5].

A huge volume of waste water is discharged in

acrylic, nylon and silk dyeing processes It was estimated that 1000 mg/L of dye was used in a typical dye bath and 100 mg/L of dye was left in the spent dye bath [6]. According to US Environmental Protection Agency and Organization for Economic Cooperation Development the amounts of non-fixed basic dyes that may be discharged in the effluent were 1% and 2–3%, respectively [7].

Dyes are colored complex organic compounds,

which has many functional groups, with high molecular weight. Basic dyes are considered one of the most toxic substances which may be responsible for permanent injury to the eyes of human and animals. [6, 8, 9]. Basic dyes generally consist positively charged ammonium atoms. Anions could be Cl-, SO4

2-, HSO4-and (COO-)2.

In some cases, species of anions could affect the dissolution of dyestuff.Solubility and persistence of these compounds are quite high in water and nature.Thus, removal of the compounds from textile industry effluents is the most important subject.

In the literature, alternative methods like

adsorption [13, 14], photocatalysis [12], biological treatment methods [17, 18], ozonation [10, 11] and coagulation-flocculation [15, 16]have been reported for the removal of basic dyes from waste waters. Some of these methods are not efficient due to large amount of

sludge generation, requirement of a higher amount of chemicals and high operation cost.

Removal of the dissolved organic compounds

by coagulation has been often mentioned in the literature [19-22]. Complex structure, high solubility and high molecular weight of the dyes make it a model compound in the study of coagulation. In this point of view, this molecules are used as model molecules of high molecular weight pollutants [23].

Electrocoagulation has more advantages than

chemical coagulation. The first advantage is that electrocoagulation does not add counter ions to the solution. For example, 8,57 g and 1,91 g undesired counter ions would be added for adding 1 gram of Al3+and Fe3+respectively.

Another advantage of electrocoagulation is that

electrocoagulation produces less acid than chemical coagulation during the formation of ferric or aluminum hydroxide. Formation of 1 mol of Fe(OH)3 or Al(OH)3 adds 3 mol H+ to the solution in conventional coagulation. In contrast, formation of Fe(OH)3 and Al(OH)3 in electrocoagulation does not add any acid to the solution.Electrocoagulation is a simple, cost-effective, and reliable wastewater treatment method with short treatment time and less generation of sludge [24, 25].

In this work, Basic Blue 3 dyestuff was

removed in a laboratory scale batch processes by electrochemically assisted coagulation. However, effect of some parameters, such as initial pH, initial concentration, current density, to the electrocoagulation and removal of the dyestuff were investigated. Basic Blue 3 was used as the model pollutant. This compound is a commonly used cationic dyestuff in textile industry. Some of the specifications of Basic Blue 3 is shown in Table 1.


Table 1. Specifications of Basic Blue 3

Name C.I. Basic Blue 3 (Astrazon Blue FGRL)

IUPAC Name

3,7-Bis(diethylamino)phenoxazin-5-ium chloride

Molecular Structure

O

N

N+

N CH3CH3

CH3CH3

Cl

Empiric Formula

C20H26ClN3O

Molecular Weight

359.89 g/mol

Color Index Number

51004

CAS Number

33203-82-6

Producer Sigma-Aldrich, Germany


Effect of Initial pH Initial pH of the dye solution is the one of the

most important parameter for the removal of dyestuff by electrocoagulation. pH is increased as the results of electrode solution and water reduction. Increasing of the ionic strength reduces the electrolyte resistance and cell potential. Presence of the aluminum supports the variation of insoluble species that occur with dye molecules, then the color of the dye solution is decreased.Although pH of the original solution of BB-3 dyestuff was 4.3, the steady-state pH was close to 6-8 at the end of the electrocoagulation processes. This indicated that aluminum species present in the solution was changed.

Table 2. Effect of pH on removal of BB-3 by electrocoagulation.

Initial pH 4 5 6 7 8

Removal efficiency (%) 96.7 96.8 96.8 96.8 97.2

Spent Aluminum (Al (Kg)/Dye (Kg))

1.83 1.86 1.92 1.95 1.99

Specific energy (KWh/Kg Dye) 17.8 26.3 35.1 40.8 47.6

Initial pH of the BB-3 measured as 4.3. Results obtained for 5 different initial pH (pH 4, 5, 6, 7, 8) is shown in Table 2. To obtain this results, Concentration-Absorbance calibration graph was plotted. BB-3 showed maximum absorbance at 654 nm wave length.

Electrocoagulation experiments achieved between pH 4-8. Initial concentration of the dye solution was C0=100 mg/L. Applied potential was 15 V for 10 minutes. For BB-3, it was identified that the dye removal efficiency was related to the pH and time, and is shown in Fig. 1.

Figure 1. Dye removal efficiency of BB-3 dyestuff related to time and pH value

As shown in inner graphic in Fig.1, the highest dye removal was occurred with pH 8 in a very short time like 4 minutes. The dye removal efficiency was 96 percent for pH 8. Thus, it could be said that more rapid BB-3 dye removal take place at highest pH values. At the end of 10 minutes, we observe that BB-3 solution with pH 8 had the highest removal efficiency with more than 97 percent. At lowest pH values (pH <6),charge neutralization of colloids by monomeric and polymeric cationic species followed by flocculation and flotation is helping in the treatment process. Another mechanism become part of the electrocoagulation at the values over pH 6: metal hydroxides (Al(OH)3) adsorb the colloids than subsequent settling.

Effect of Initial Dye Concentration Here we prepared BB-3 dye solutions with

different initial concentrations (C0) between 50-600 mg/L. Than we investigated effect of this parameter to the electrocoagulation process.


Figure 2.Dye removal efficiency related to the BB-3 initial concentration

Table 3. Effect of initial dye concentration on removal of BB-3 by electrocoagulation. A: Initial Concentration (mg/L), B: Removal Efficiency (%), C: Spent Aluminum (Al (Kg)/Dye

(Kg)), D: Specific energy (KWh/Kg Dye)

Fig. 2 and Table 3 show the dye removal efficiency related to the BB-3 initial concentrationand effect of initial dye concentration on removal of BB-3, respectively. At the end of 6 minutes, when the removal efficiency of the solutions between 50-400 mg/L varied between % 92-95, it reduces % 72 and 60 for 500 and 600 mg/L respectively.

Efficiency of BB-3 initial concentration to the dye removal related to the time, is shown in Fig. 3.BB-3 removal efficiencies at the end of 10th and 20th minutes were 96 and 99 percent, respectively. Increase in C0,decreased the removal efficiency. Large amount of the BB-3 was removed in 6 minutes in C0 between 50-400 mg/L, while the removal time extended to 10 minutes for 500 and 600 mg/L.This is due to the fact that at high C0, polymeric Al species andAl(OH)3 (produced via electrode dissolution) are insufficientto interact with a large number of dye molecules [25].BB-3 removal efficiency was increased after 6th minutes due

to the decreasing of dye concentration at reactors with high C0. Thus, removal efficiency for all C0 values were become equal at the end of 10th minutes. However, a largenumber of intermediates formed in the solution block the activesite of the Al electrode and decrease thecolor removal efficiencies [25].

Figure 3. Efficiency of BB-3 initial concentration to the dye removal related to the time

BM-3 removal was maintained constant for low initial concentration values.This behavior explains the importance of the chargeneutralization in the coagulation of BB-3. If the number of negatively charged sites is below the stoichiometric requirements of BB-3, the dyeremoval percentage decreases and the excess ofBB-3 remains insolution.

Effect of Current Density Amount of the supporting electrolyte was

differed as 1, 1.5, 2, 2.5, 3 g for adjusting the conductivity and current density. Therefore currents of 1; 1.5; 1.8; 2; 2.4 A were achieved at 15 Volt, respectively (Table 4).

Table 4. Effect of current density on removal of BB-3 by electrocoagulation.(C0 = 100 mg/L; V = 1 L; E = 15V; t = 2 min.)

Calculated current densities changed between 139-333 A/m2. Dye removal efficiency was increased to % 92 at the end of 2nd minuteswith 333 A/m2. After 4th and 10th minutes, removal efficiency was increased to % 96 and 97, respectively (Fig. 4.).At high current densities, impedance between electrodes is decreased and therefore migration speed of the molecules and ions to the electrodes is increased.

A 50 100 200 300 400 500 600 B 92.5 96.5 97.7 91.1 94.2 72.1 60.8 C 3.89 1.87 0.92 0.66 0.48 0.50 0.50 D 32.4 15.4 7.6 5.4 3.9 4.0 3.95

Current (A)

1 1.5 1.8 2 2.4

Removal efficiency (%)

12.85 16.5 22.24 61.85 91.90

Current density (A/m2)

138.9 208.3 250 277.8 333.3

Specific Energy (kWh/kg dye)

38.92 45.42 40.46 16.17 13.06


Figure 4. efficiency of current density to the removal of BB-3 related to the time

From the supporting electrolyte (NaCl) quantity point of view, salt concentration does not take an important role in disruption and thus, increase in ionic strength does not affect directly the removal efficiency of BB-3 from the solution. of the molecules.Thus, it can be assumed that thecoagulation by the compression of the double layer, does not play an important role in theoverall process.On the other hand, the cell potentialdecreases strongly with increasing concentration ofNaCl, due to the decrease in the ohmic losses [21].However, due to we maintained the potential constant for all salt concentrations, current density was increased. Fig. 5 shows the current density related specific energy graphic that calculated with BB-3 removal data at the end of 2nd minutes.Specific energy was decreased due to the BB-3 percentage was increased in a very short time by increasing the current density. In addition, making the current densityconstant is recommended for preventing the excess oxygen release, avoiding the disruptive effects like heat, decreasing the electrode and energy consumption.

Figure 5. Efficiency of current density to the specific energy.

CONCLUSION

This work showed that BB-3 dyestuff could be removed easily from the solution by electrocoagulation process where aluminum electrodes were used. Here, pH was the most important parameter. While the pH was increased from acidic to basic, dye removal speed is increased due to the transformation of dyestuff to the leuco form. Most efficient dye removal was achieved at pH 8.

Another investigated parameter is initial dye concentration (C0). Increase in C0 decreased the removal efficiency. Substantial amount of BB-3 was removed at 6 minutes for C0between 50-400 mg/L. This time was extended to 10 minutes for 500-600 mg/L.

From the supporting electrolyte (NaCl) quantity point of viewsalt concentration does not take an important rolein disruption and thus, increase in ionic strength does not affect directly the removal efficiency of BB-3 from the solution. Specific energy was decreased due to the BB-3 percentage was increased in a very short time by increasing the current density. In addition, making the current density constant is recommended for preventing the excess oxygen release, avoiding the disruptive effects like heat, decreasing the electrode and energy consumption.

REFERENCES

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[2] I. D. Mall, V. C. Srivastava, N. K. Agarwal ve I. M. Mishra, «Adsorptive removal of malachite green dye from aqueous solution by bagasse fly ash and activated carbon-kinetic study and equilibrium isotherm analyses,» Colloids Surf., A: Physicochem. Eng. Aspects, cilt 264, pp. 17-28, 2005.

[3] S. Singh, V. C. Srivastava ve I. D. Mall, «Multistep optimization and residue disposal study for electrochemical treatment of textile wastewater using aluminum electrode,» Int. J. Chem. React. Eng., cilt 11, pp. 1-16, 2013.

[4] L. Szpyrkowicz, C. Juzzolinove S. N. Kaul, «A comparative study on oxidation of disperses dyes by electrochemical process, ozone, hypochlorite and Fenton Reagent,» Water Res., cilt 35, pp. 2129-2136, 2001.

[5] C. Wu, Y. Wang, B. Gao, Y. Zhao ve Q. Yue, «Coagulation performance and floc characteristics of aluminum sulfate using sodium alginate as coagulant aid for synthetic dying wastewater treatment,» Sep.Purif. Technol., cilt 95, pp. 180-187, 2012.

[6] K. Marungruengve P. Pavasant, «Removal of basic dye (Astrazon Blue FGRL) using macroalgaCaulerpalentillifera,» J. Environ. Manage, cilt 78, pp. 268-274, 2006.

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Strain Pseudomonas sp. K9 and Cloning of the tmr2 Gene Associated with an ISPpu12,» World J. Microbiol. Biotechnol., cilt 27, pp. 1323-1329, 2011.

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Structural, Elastic and Electronic Properties of Fe2TiSi Full-Heusler Compound

Mustafa ÖZDURAN and Raşit UMUCU

Ahi Evran Üniversitesi Fen Edebiyat Fakültesi, Fizik Bölümü, 40100-Bağbaşı-Kırşehir/TURKEY

*corresponding author:[email protected]

Keywords:Heusler alloys, density-functional theory, electronic structure.

INTRODUCTION

Heusler alloys have attracted great interest during the past decades because of their possible applications in spintronics or magnetoelectronics [1, 2]. The first Heusler alloys studied were crystallized in an L21structure which consists of four fccsublattices. Ideally these alloys have composition X2YZ. In general X and Y are transition metals and Z is a B-subgroup element. Yabuuchi et al. [3] have been studied for the electronic and transport properties of Fe2TiSi alloy in the L21 phase. They have observed that this material is non-magnetic alloy. Mienert et al. [4] have prepared the single-phase film of the full-Heusler compound Fe2TiSi alloy using magnetron sputtering. They have found to be a semiconductor with a gap of 0.4 eV. The structural identification of full Heusler Fe2TiSi alloy was measured using X-ray powder diffraction (XRD) by Raghavan [5]. Although considerable progress has been made in theoretically describing the structural and electronic properties of Fe2TiSi alloy, many of elastic properties of this material are still not well established. This paper is organized as follows. In Sec. II, we describe our calculational methods, and Sec. III is devoted to the discussion of the results of our calculations for the structural and elastic properties of Fe2TiSi Heusler alloy, including a comparison with previous available data. The electronic structure of this alloy is examined. A conclusion is provided in Sec. IV. Method The calculations were performed to obtain the structural, electronic and elastic properties of Fe2TiSi using first-principles calculations based on the density-

functional theory (DFT) within the generalized gradient approximation (GGA) as implemented in the Vasp-MedeA package [6, 7]. Plane-wave energy cut-off of 260 eV were used in VASP calculation. The k-points samplings were 5x5x5 for VASP in the Brillouin zone for Fe2TiSi, according to the Monkhorst–Pack scheme [8]. The structure was relaxed until the convergence in energy of 1x10−5eV was reached. In the VASP calculations, the Methfessel–Paxton smearing [9] with broadening of 0.225 eV was used for relaxation.


We calculated the ground state lattice parameters of Fe2TiSi alloy and compared this with the available experimental and theoretical values [3-5]. The computed values of lattice constants, bulk modulus, Shear and Young modulus, elastic constants and B/G ratios for the Fe2TiSi alloy in Table 1.

mailto:*[email protected]


Table 1. Calculated lattice constants (in Å), Bulk modulu (in GPa), Shear and Young modulus (E, GPa), Poisson’s ratio () and elastic constantsCij(in GPa)for Fe2TiSi in the L21 phase.

Referances a(Å) B E C11 C12 C44 G B/G

Fe2TiSi This Work 5.684 190.682 0.194 349.826 441,3692 130,6772 140,544 146,465 1,302

GGA [3] 5.685

Exp.[4] 5.709

Theory [5] 5.717

Exp.[5] 5.720

The calculated lattice constant for Fe2TiSi are in good

agreement with the available theoretical and

experimental data. The elastic constants (Cij) are

valuable parameters for understanding how a material

behaves based on its structural stability and ductility

properties. There are three independent elastic

constants (C11, C12 and C44) in cubic crystals. The

conditions of stability reduce to a simple form: C11>0,

C12>0, C44> 0 and C11−C12> 0. The elastic constants of

the full-Heusler alloy Fe2TiSi are calculated using the

approximation reported in [10]. Unfortunately, there

are no experimental and theoretical data available in

the literature regarding the elastic constants of this

material. An important material parameter is the B/G

ratio, as an indication of ductility and brittleness.

According to the Pugh criteria [11], a high B/G ratio

indicates ductility, while a low B/G ratio indicates

brittleness. The critical value, separating ductile

materials from brittle ones, is 1.75. The B/G value is

1.302 for Fe2TiSi in the L21 phase. Figure1 shows the

electronic band structure of Fe2TiSi alloy in the L21

phase. This alloy is a semiconductor because there is a

gap at the Fermi level. The calculated value of the band

gap is found to be 0.46 eV. This value is in good

agreement with available data [3, 4]. Our calculated

band structures for Fe2TiSi alloy are in good agreement

with previously reported result [3].

Figure 1.The electronic band structure of Fe2TiSi in the L21 phase.

The character of the band states has been identified

using the calculated total and partial densities of states

for this alloy in Figure 2. The bands above the Fermi

level, are dominated by Fe-d states and Si-s states.On

the other hand, the bands below the Fermi level mainly

dominated by Fe-d states.

Figure 2. The total and projected density of states for Fe2TiSi in the L21 phase.


CONCLUSION

The structural, electronic and elastic properties of

Fe2TiSi have been investigated using the

pseudopotential plane-wave method. Our main results

and conclusions can be summarized as the calculated

structural properties (lattice constant and bulk

modulus) in the L21 phase, which are in good

agreement with the values reported in the literature.

The elastic constants of Fe2TiSi alloy have been

computed for first time using DFT. The electronic band

structures were calculated and compared in the

available data for this material, in the L21 phase.

REFERENCES 1Žuti´c, I; Fabian,J; Das, Sarma, S; Rev. Mod. Phys. 2004, 76, 323. 2Hirohata, A; Takanashi, K;J. Phys. D Appl. Phys. 2014, 47, 193001.3Yabuuchi, S; Okamoto, M; Nishide, A; Kurosaki, Y;Hayakawa, J; Applied Physics Express 2013,6, 025504. 4Meinert, M. Geisler, M. P. Schmalhorst, J. Heinzmann, U. Arenholz, E. Hetaba, W; Stöger-Pollach, M;Hütten A;Reiss, G;Physical Review 2014, B90, 085127 5Raghavan, V;Journal of Phase Equilibria and Diffusion, 2009,30, 393. 6Kresse, G; Hafner, J; Phys. Rev. 1993,B47, 558. 7Kresse, G; Furthmuller, J; Phys. Rev. 1993, B54, 11169. 8Monkhorst, H. J; Pack, J.D; Phys. Rev. B 1976, 13, 5188–5192. 9Methfessel,M; Paxton, A. T;. Phys. Rev. 1989,B 40, 3616–3621. 10Arıkan,N; Journal of Physics and Chemistry of Solids 2013,74, 794. 11Pugh, S.F;Philos. Mag. 1954, 45, 823.


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· 2017-03-06 · ii Chair of the Conference Prof. Dr. Ahmet TUTAR Co-Chair of the Conference...

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