Utilization of Agricultural Waste for the Removal of Organic Pollutants from

Aqueous Media

Muhammad Iqbal Bhanger

National Center of Excellence in Analytical Chemistry,University of Sindh, Jamshoro, Pakistan

This presentation is focused on :

a preview about the preconcentration /enrichment, determination and removal of various organic pollutants by solid phase extractionusing natural material (e.g. agriculture waste)

Common sources of organic pollutants in our environment

Industrial effluents

Pesticides applications

Municipal discharge

Power plants

Oil spillage

Environmental trace organic analysis

Several problem were encountered in theorganic micropollutants, where the analysishad to face many different compoundso c c u r r i n g a t t r a c e c o n c e n t r a t i o n s .

Therefore, the need of a reliable data onoccurrence of such micropollutants in theenvironment was an important driving forceini t iat ing the development of modernanalytical techniques e.g. SPE and procedure.

Solid Phase extraction

Adsorption � a surface phenomenon

Retention of ions / molecules on thesurface due to certain physical andchemical attractive forces. The surfaceinclude the outside of the adsorbent aswell as pores in high surface area perunit volume.

Adsorbent

Adsorbate

Removal of bound material is called desorption i.e. opposite of adsorption

Selective solute binding

SPE - an increasingly popular technique in comparison to the classical solvent �solvent extraction because of :

high enrichment factor, high recovery, rapid phase separation, low cost, low consumption of organic solvents the ability of combination with other

detection techniques in the form of on-line or off-line mode.

Synthetic Natural

Sorbents used in solid phase extraction

Activated carbon Clay/MineralsAlumina Fly ashSilica gel Agricultural waste Ion-exchange Resins XAD modified resins Coconut husk

Rice huskGroundnut huskApple residuePlant bushesOnion skin ZeoliteGeoliteRiver sand

Advantages of Natural Sorbent

Inexpensive

Environmental friendly

Freely Available

Active

Stable

Accessible

Easy to reuse

Lab. Set-up for the Removal of Pollutant using

Solid �phase extraction

Materials commonly used for extraction chemical substances from water

Ion-imprinted polymers Immunoaffinity based sorbents Nano-composite materials Functionalized chelating polymers /

Inorganic material Agriculture wastes Sand, Clay, industrial waste Microbial biosorbents e.g. algae, fungi,

bacteria

Choice of adsorbentLow inorganic matter contentEase of activationAvailability and low costLow degradation

Factors affecting adsorptionPhysical nature of the adsorbent �pore structure, functional groups, polarity, molecular weight, size and Solution conditions e.g. pH, ionic strength and the adsorbate concentration

Scheme for the preparation of palladium Ion imprinted material.

Daniel, Babu and Rao, Talanta (65) 441, 2005

Agriculture MaterialAgriculture Material

Solid phase Extraction and separation of

(a) Cr(III) and Cr(VI)

(b) Cd(II) using sawdust as an adsorbent (relatively abundant and inexpensive material)

Green Chemistry

Sorption using agriculture waste material

Extraction of Cr (III) and Cr (VI) ions with Separation of chromium specie on saw dust as a function of pH

0

20

40

60

80

100

0 2 4 6 8

pH

% S

orpt

ion

Cr(III) Cr(VI)

Saima, Bhanger and Khuhawar,Anal. Bioanal. Chem. 383, 619-624, 2005

Easy, simple and economical

Both specie of Cr can be adsorbed without the need of oxidation / reduction.

Rapid and sensitive

Can be designed on a large scale

Benefits

Removal of Cd(II) ions both treated and untreated

sawdust was used Surface area 400 cm2

Maximum adsorption at pH 4 - 5

Sorption using Sawdust

Saima, Najma, Bhanger and Khuhawar,

J. Hazard. Mater. B139 116-121, 2007

Figures showing uptake of Cd (II) ion on saw dust as a function of pH

Untreated

Treated

0.0

0.5

1.0

1.5

2.0

0 2 4 6 8 10pH

q (m

etal

upt

ake)

mg

g-1

Online Solid Phase Extraction of Cr(III)and Cr(VI)

Motomizu et al. Talanta, 68, 388, 2005

Solid Phase Extraction of Trace Organics from WaterSolid Phase Extraction of

Trace Organics from Water

Lab. Methods for the Removal of Pollutant using Solid �

phase extraction

S-1(sorbents treated with doubly distilled deionized water and

dried at 283K for 8hrs)

0

20

40

60

80

S-1

Per

cen

t so

rpti

on

BFA

RB

APS

MOP

RH

PNH

AH

CNS

SW

CC

DS

NTL

0

20

40

60

80

100

S-2 S-3

S-2(sorbents treated with 0.1M nitricacid S-3(sorbents treated with methanol)

Per

cen

t so

rpti

on

BFA

RB

APS

MOP

RH

PNH

0.2 g of each sorbent, 20 cm3 of1.1î10-3 M toluene concentration,30 min agitation time, pH 6 and303K.

0.2 g of each sorbent, 20 cm3 of1.1î10-3 M toluene concentration, 30min agitation time, pH 6 and 303K.

Investigation of agriculture waste Investigation of agriculture waste material as sorbentsmaterial as sorbents

Solid phase extraction of BTEC, phenols and

pesticides

Solid phase extraction of BTEC, phenols and

pesticides

AnalyteLimit of Detection

(ìg/ml)US EPA Recommended Limit in water (ìg/ml)

Phenol 0.1 0.21

4-Chlorophenol 0.08 0.7

2,4-Dichlorophenol 0.08 0.8

1 = Phenol

2 = 4-Chlorophenol

3 = 2,4-Dichlorophenol

AnalyteLimit of Detection

(ìg/ml)

US EPA Recommended Limit

in water (ìg/ml) Methylparathion 0.05 0.01

Triazophos 0.05 0.01

Endosulfan 0.1 0.62

Cypermethrin 0.1 0.43

(1)

(2)

(3)

(4)

(1) = Methyl parathion

(2) = Triazophos

(3) = Endosulfan

(4) = Cypermethrin

AnalyteAnalyteLimit of DetectionLimit of Detection

(ìg/ml)(ìg/ml)US EPA Recommended US EPA Recommended Limit in water (ìg/ml) Limit in water (ìg/ml)

MethylparathionMethylparathion 0.050.05 0.010.01

TriazophosTriazophos 0.050.05 0.010.01

EndosulfanEndosulfan 0.10.1 0.620.62

CypermethrinCypermethrin 0.10.1 0.430.43

(1)(1)(1)

(1)(1)

(2)

(3)(4)

(1) = Methyl parathion

(2) = Triazophos

(3) = Endosulfan

(4) = Cypermethrin

20

40

60

80

0 25 50 75 100 125Agitation time (min)

Per

cen

t so

rpti

on

Benzene TolueneEthylbenzene Cumene

10

20

30

40

50

60

70

80

0 25 50 75 100 125

Agitation time (min)

Per

cen

t so

rpti

on

Benzene TolueneEthylbenzene Cumene

Effect of agitation time (5-120 min) onthe percent sorption of BTEC onto 0.1 gRB, 25 cm3 of 100 g/ ml sorbateconcentration of BTEC at pH 6 and 303 K.

Effect of agitation time on thepercent sorption of BTEC onto 0.1 gMOP, 25 cm3 of 100 g/ ml sorbateconcentration of BTEC at pH 6 and303 K.

Percent sorption and percent recovery of benzene, toluene and ethylbenzene from

contaminated water by rice bran

Analyte

Concentration of analyte determined(µg/ ml)

Concentration of analyte determined with spiked

sample (µg/ ml)

%sorption % recovery

before sorption

after sorption

Benzene 0.451 10.45 0.22 98 96.2 Toluene 0.334 10.33 0.1 99 97.3 Ethylbenzene 0.214 10.21 0.1 99 97.3

Cumene N.D. _ _ _ _

Mubeena, Bhanger, Hasany , J. Agric. Food Chem. 53, 8655-8662 (2005).

Application of method on contaminated water sample using treated Moringa oleifera seeds

Analyte

Concentration of analyte determined in spiked

contaminated sample ((µg/ ml) % sorption

% recovery

Before sorption

After sorption

Benzene 10.44 0.17 98.4 96.2

Toluene 10.33 0.1 99.03 98.3

Ethylbenzene 10.22 0.1 99.02 98.2

Cumene - - - -

Mubeena, Bhanger, Hasany, J. Hazard. Mater. 141, 546-556 (2007)

Percent sorption and percent recoveries of 4-CP and 2,4-DCP from industrial wastewater sample onto rice husk.

Analyte Wastewater (ìg/ml)Removal* (%) Recovery* (%)

with 6 ml methanol

Phenol ___ ___

4-Chlorophenol 98 ± 0.8 96 ±1.2

2,4-Dichlorophenol 99 ± 0.2 99 ± 0.6

S.No Characteristics Values

1 pH 7.3

2 EC (ìS cm-1) 286

3 Phenol N.D

4 4-CP (ìg ml-1) 0.4

5 2,4-DCP (ìg ml-1) 1.5

Mubeena, Bhanger, Hasany, J. Hazard. Mater.

B 128, 44-52 (2006)

Sorbents Surface water Ground water

Removal Recovery Removal Recovery

Rice bran 99 98 99 98

Bagasse fly ash 99 98 99 98

Moringa oleifera pods 98 97 98 97

Rice husk 97 96 97 96

Percent sorption and percent recoveries of MP from water samples onto RB, BFA,

MOP and RH

Surface Characteristics of treated agriculture waste sorbents

Parameters MOP Rice husk

Total intrusion volume (ml/g) 0.72 0.01 0.694 0.046 Total pore area (m2 g-1) 27 0.8 17 0.6 Average pore diameter (nm) 86 1.3 51 1.5

Carbon % 97.6 0.02 24.1 0.05

SiO2% - 75.9 K2O% 2.4 0.02 - CaO % 1.5 0.03 0.28 0.02 Fe2O3 % 1.1 0.01 0.3 0.03 Cellulose weight % 15.6 0.05 0.4 0.04 Hemicellulose % 11.1 0.07 0.6 0.02 Lignin % 10.7 0.08 0.5 0.01 Crude fibre % 13.8 0.06 0.8 0.02

Rice huskMoringa oleifera seed pods

Bagasse fly ash

Scanning electron microscope pictures of natural activated adsorbents showing heterogenous surfaces

SEM image of the rice bran activated chemically and thermally.

Proposed Mechanism of Sorption

� The sorption mechanism may be deduced from the involvement ofdifferent functional groups present on the sorbents surfaces such as−OH, NH2 metal oxides (via ash content i.e. Si−O−Si) and fibrecarbonaceous CxOH. These functional groups may be dissociated atdifferent pH values as per their acidic dissociation constants andconsequently take part in surface complexation / exchange of sorbatespecies.

� The surfaces are expected to be negatively charged, which mayfacilitate the sorption of positively charged species at low pH ontothese active groups via surface complexation.

.00� −OH = −O− + H+

.00

� CxOH = −CxO− + H- NH2 = - NH3

+

Conclusion

Adsorption of trace organics on solid surface from the aqueous solutions present the most wide spread use of natural material. The use of agriculture waste also add on to the Green Chemistry.

Molecular size, molecular structure, steric form of sorbatealso influences the sorption. More soluble a substance is inwater; its low sorption is likely to occur on the sorbentsurface e.g. phenol as compared to nitrophenol.

The equilibrium uptake and adsorption yield were highestfor the treated materials, which was expected, because ofthe greater specific surface area and the microporousstructure of treated materials as compared with untreatedmaterials.

The results of surface characterization indicate thatrice bran, rice husk, and Moringa oleifera pods arecomposed of substantial amount of cellulose,hemicellulose, lignin and protein besides ash. Theseactive sites may display different affinities for varioussorbed species.

Therefore, the quantity and nature of active sites inthe cells of such biomaterials may be a major factorin the binding behavior of sorbed species at a givenpH in sorptive solution. The lignin content mayincrease the sorption of organics on the sorbentssurfaces of botanical origin.

My co-workers

Dr. Mubeena Akhter, Dr. Saima Q. Memon

and

Organizers of Pak-Turk Bilateral Workshop on Chemical Sciences especially

Prof. M.Yilmaz, Prof. Mustafa Ersoz and Dr. Shahabuddin Memon.

Acknowledgment

A view of NCEAC, Jamshoro, Pakistanvisit us www.ceacsu.edu.pk

A view of NCEAC, Jamshoro, Pakistanvisit us www.ceacsu.edu.pk