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Transcript of static-content.springer.com10.1007... · Web viewSUPPLEMENTARY INFORMATION SHEET Facile synthesis...
SUPPLEMENTARY INFORMATION SHEET
Facile synthesis of TiO2-PC composites for enhanced photocatalytic abatement of multiple
pollutant dye mixtures: A comprehensive study on the kinetics, mechanism and effects of
environmental factors
Priyanshu Verma, Sujoy Kumar Samanta*
Department of Chemical and Biochemical Engineering,Indian Institute of Technology Patna, Bihta, Patna – 801106 (India)
*Corresponding author E-mail address: [email protected]
S1. Details of instruments used for catalyst characterization:Instrument Company/ Manufacturer Model Conditions
SEM TESCAN VEGA3 LMUHV: 30.0 kV at different
magnifications.
EDX TESCAN + BrukerTescan VEGA3 LMU with
energy-dispersion spectrometer (EDS) Bruker XFlash detector
HV: 30.0 kV
TEM JEOL JEM 2100 HV: 200.0 kV at 20000x magnification.
XRD Rigaku TTRX-IIICuKα (1.542 Å) radiation;
2θ range: 10-80°; Scan rate: 2°/min; Scan step 0.02°.
PL Perkin ElmerLS 55
Fluorescence spectrometer
Excitation@200 nm. The fluorescence was recorded
between 300-650 nm.
BET/N2 IsothermQuantachrome
InstrumentsNOVA-1000 Ver. 3.70
The samples were degassed at 500 °C for 12 hrs. Multiple N2
adsorption and desorption points were recorded between the
relative pressure range of 0.020–0.992 at 77.4 K.
TGA Perkin Elmer STA 6000Heat from 30 °C to 950 °C at the
rate of 20 °C/min under continuous N2 flow @ 20 ml/min.
UV-Visible Spectrophotometer
Thermo Scientific EvolutionTM 200 series1.5 mg of photocatalyst was
dispersed in 5 ml of Millipore water before analysis.
CHNS Elementar vario MICRO cubeAt high temperature in the oxygen rich environment using Helium as
inert carrier gas.
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S2. Digital photocatalytic reactor used in this study:
A self customized batch photocatalytic reactor was used in this study. This reactor basically has
two parallel UV-rods (PHILIPS TUV 11W G11 T5, a cylindrical low pressure Hg lamp with
irradiation area about 96.94 cm2). It also contains one hot plate cum magnetic stirrer and a
temperature probe inside a perfectly dark enclosure to avoid the surrounding lights and internal
reflections. The reaction vessel used was a beaker with diameter and top exposed area of 50 mm
and ca. 19.63 cm2, respectively. The photometric data of UV source or lamp have been shown in
Fig. S1(a). The UV fluence rate was measured with the help of EIT UV Power Puck® II
Radiometer and was found about 4.918 mW/cm2 (UV-C) at the surface of the single low pressure
Hg lamp. The schematic of the reaction setup is given in Fig. S1(b).
Fig. S1 (a) Emission profile of the low pressure Hg lamp (UV lamp).
Fig. S1 (b) Schematic of the batch photocatalytic reactor.
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S3. Reaction conditions used to study the influence of different environmental factors:
Variable Factors (3 Level) Other Factors UV Exposure*
Salt Concentration
(NaCl)
1 g/lVolume: 5 ml of Mixed Dyes;Catalyst Dose: 1 mg/ml;Stirring/Mixing Speed: 500 RPM;pH: Neutral; Ambient Temperature: (24 ± 2 °C);Chemical Oxidants: None;Reactor Design Parameters: Fixed or Constant
30 min5 g/l
10 g/l
pH Buffer
pH 4.0Volume: 5 ml of Mixed Dyes;Catalyst Dose: 0.5 mg/ml;Stirring/Mixing Speed: 500 RPM;Ambient Temperature: (24 ± 2 °C);Chemical Oxidants: None;Salts and Additives: NoneReactor Design Parameters: Fixed or Constant
150 minpH 7.0
pH 9.2
Temperature
25 °CVolume: 5 ml of Mixed Dyes;Catalyst Dose: 1 mg/ml;Stirring/Mixing Speed: 500 RPM;pH: Neutral; Chemical Oxidants: None;Salts and Additives: NoneReactor Design Parameters: Fixed or Constant
15 min35 °C
45 °C
Stirring/Mixing Speed
100 RPMVolume: 5 ml of Mixed Dyes;Catalyst Dose: 1 mg/ml;pH: Neutral; Ambient Temperature: (24 ± 2 °C);Chemical Oxidants: None;Salts and Additives: NoneReactor Design Parameters: Fixed or Constant
15 min500 RPM
1000 RPM
Catalyst Dose
0.5 mg/mlVolume: 5 ml of Mixed Dyes;Stirring/Mixing Speed: 500 RPM;pH: Neutral; Ambient Temperature: (24 ± 2 °C);Chemical Oxidants: None;Salts and Additives: NoneReactor Design Parameters: Fixed or Constant
15 min1.0 mg/ml
1.5 mg/ml
*UV Exposure time duration was varied due to different observed degradation speed of mixed pollutant dyes in each instance.
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S4. Signature spectrum of different pollutant dyes used in this study:
Fig. S2 represents the individual dye’s UV-Visible absorption spectrum in the scan range of 200
to 750 nm. In this figure, individual λmax has been identified and considered as 667 nm, 553 nm,
518 nm and 466 nm for MB, RhB, Amaranth and MO, respectively. The absorbance at
individual λmax has been calibrated as the remaining concentration of the respective pollutant dye
in a synthetic pollutant dye mixture.
Fig. S2 UV-Visible absorption spectra of individual pollutant dyes.
The percentage removal of individual pollutant dye can be calculated using the given formula:
Removal∨decomposition∨degradation percentage=CO−C t
CO∗100(%)
Where, CO is the initial concentration or absorbance at λmax of individual pollutant dye and C t is
the concentration or absorbance at λmax of individual pollutant dye at time ‘t’.
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S5. Degradation kinetic analysis:
The kinetic data of photocatalytic degradation of individual pollutant dye in a synthetic pollutant
dye mixture using TiO2 and TiO2-PC photocatalysts were analyzed using a pseudo-first-order
kinetic model which was proposed by Langmuir–Hinshelwood and is as follows:
dCdt
=−kC
Where C represents the concentration of individual pollutant dye in a synthetic pollutant dye
mixture at time ‘t’, and ‘k’ is the apparent degradation rate constant. The integration of above
equation yields:
ln (CO
C )=kt
Plotting ln(C0/C) as a function of time yields the ‘k’ values. Here, C0 is the initial concentration
of individual pollutant dye in a synthetic pollutant dye mixture. A linear relation between
ln(C0/C) and ‘t’ was observed in the Fig. 8. Then, the individual pollutant dye’s ‘k’ value for the
photocatalytic degradation of synthetic pollutant dye mixture using TiO2 and TiO2-PC
photocatalysts were determined graphically; they are listed in Table 1. The agreement between
experimental data and the results obtained using the pseudo-first-order kinetic model was
evaluated from the coefficients of determination (R2). The high values of R2 in most of the cases
revealed that the photocatalytic degradation of individual pollutant dyes in a mixed synthetic
pollutant dyes matrix using TiO2 and TiO2-PC photocatalysts obeyed the pseudo-first-order
kinetic model. In addition, the first half life of individual pollutant dye was calculated using a
given formula:
t 1/2=0.693
k
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S6. Characterization results:
E
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Fig. S3 EDX spectrum of TiO2, PC and TiO2-PC composite.
Fig. S4 EDX map of TiO2-PC nano-micro composite.
Fig. S5 TEM image of bare-TiO2 nanoparticles used for the preparation of TiO2-PC nano-micro composites.
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Fig. S6 PL patterns of bare-TiO2, PC and TiO2-PC nano-micro composite.
Fig. S7 (a) UV-Visible absorption spectra of bare-TiO2 and TiO2-PC nano-micro composite and (b) Band gap measurement using the Tauc plot method.
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S7. Visuals of mixed synthetic pollutant dyes matrix during photocatalytic degradation:
Fig. S8 Initial synthetic pollutant dye mixture (a); Dye mixture+TiO2-PC (b) and Dye mixture+TiO2 (c), after 30 mins of dark stirring; UV photolysed (4 hr) initial synthetic pollutant
dye mixture (d).
Fig. S9 Synthetic pollutant dye mixture treated with bare-TiO2: Here, 1, 2, 3, 4, 5, 6 and 7 show the degraded samples after 30, 60, 90, 120, 150, 180 and 240 min, respectively.
Fig. S10 Synthetic pollutant dye mixture treated with TiO2-PC: Here, 1AC*, 2AC, 3AC, 4AC, 5AC, 6AC and 7AC show the degraded samples after 30, 60, 90, 120, 150, 180 and 240 min,
respectively.
*Note: ‘AC’ basically indicates ‘added processed carbon (PC)’.
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Fig. S11. Mass spectra of: (a) Initial; (b) bare-TiO2 treated; (c) TiO2-PC treated synthetic pollutant dye mixtures.
S8. Effect of different PC weight fractions on photocatalytic activity of TiO2-PC composites:
Fig. S12 RhB degradation performance of TiO2-PC composites with different PC weight fractions (Catalyst dose= 1 g/l; Reaction volume= 10 ml; RhB concentration = 5 ppm; UV-C
irradiation= 1 h).
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