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Preparation and Characterization of Chitosan Thin Films on Mixed-Matrix Membranes for Complete Removal of Chromium.

Nayak V, Jyothi MS, Balakrishna RG, Padaki M, Ismail AF - ChemistryOpen (2015)

Bottom Line: Structure property elucidation was carried out by X-ray diffraction, microscopy, spectroscopy, contact angle measurement, and water uptake studies.The increase in hydrophilicity followed the order: PSf < PSf/TiO2 < PSf/TiO2/CS membranes.The observations reveal 100 % reduction of Cr(VI) to Cr(III) through electrons and protons donated from OH and NH2 groups of the CS layer; the reduced Cr(III) species are adsorbed onto the CS layer via complexation to give chromium-free water.

View Article: PubMed Central - PubMed

Affiliation: Center for Nano and Material Sciences, Jain University Ramanagaram, Bangalore, 562112, India.

ABSTRACT
Herein we present a new approach for the complete removal of Cr(VI) species, through reduction of Cr(VI) to Cr(III), followed by adsorption of Cr(III). Reduction of chromium from water is an important challenge, as Cr(IV) is one of the most toxic substances emitted from industrial processes. Chitosan (CS) thin films were developed on plain polysulfone (PSf) and PSf/TiO2 membrane substrates by a temperature-induced technique using polyvinyl alcohol as a binder. Structure property elucidation was carried out by X-ray diffraction, microscopy, spectroscopy, contact angle measurement, and water uptake studies. The increase in hydrophilicity followed the order: PSf < PSf/TiO2 < PSf/TiO2/CS membranes. Use of this thin-film composite membrane for chromium removal was investigated with regards to the effects of light and pH. The observations reveal 100 % reduction of Cr(VI) to Cr(III) through electrons and protons donated from OH and NH2 groups of the CS layer; the reduced Cr(III) species are adsorbed onto the CS layer via complexation to give chromium-free water.

No MeSH data available.


Experimental setup for the removal of CrVI: a) CrVI reduction to CrIII in the dark; b) CrIII adsorption onto the membrane surface; c) desorption of CrIII from the membrane surface.
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fig14: Experimental setup for the removal of CrVI: a) CrVI reduction to CrIII in the dark; b) CrIII adsorption onto the membrane surface; c) desorption of CrIII from the membrane surface.

Mentions: The removal of CrVI was carried out using PSf/TiO2/CS and PSf/CS membranes. To evaluate the efficiency of the membranes in the dark and sunlight (intensity >700 W m−2) the prepared membranes of 100 cm2 area were cut and stuck to a trough using double-sided tape as represented in Figure 14. A CrVI solution (10 ppm) was used, and acidic and basic conditions were maintained with 0.1 n formic acid and NaOH solutions, respectively. After every 10 min, 10 mL of the sample were drawn and analyzed for the presence of chromium using UV/Vis spectroscopy (Shimadzu, Model UV-1800) at λmax=350 nm. C/CO was evaluated (where C=concentration of treated sample and CO=concentration of feed sample) and plotted against time to analyze the residual concentration of CrVI.48


Preparation and Characterization of Chitosan Thin Films on Mixed-Matrix Membranes for Complete Removal of Chromium.

Nayak V, Jyothi MS, Balakrishna RG, Padaki M, Ismail AF - ChemistryOpen (2015)

Experimental setup for the removal of CrVI: a) CrVI reduction to CrIII in the dark; b) CrIII adsorption onto the membrane surface; c) desorption of CrIII from the membrane surface.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4522177&req=5

fig14: Experimental setup for the removal of CrVI: a) CrVI reduction to CrIII in the dark; b) CrIII adsorption onto the membrane surface; c) desorption of CrIII from the membrane surface.
Mentions: The removal of CrVI was carried out using PSf/TiO2/CS and PSf/CS membranes. To evaluate the efficiency of the membranes in the dark and sunlight (intensity >700 W m−2) the prepared membranes of 100 cm2 area were cut and stuck to a trough using double-sided tape as represented in Figure 14. A CrVI solution (10 ppm) was used, and acidic and basic conditions were maintained with 0.1 n formic acid and NaOH solutions, respectively. After every 10 min, 10 mL of the sample were drawn and analyzed for the presence of chromium using UV/Vis spectroscopy (Shimadzu, Model UV-1800) at λmax=350 nm. C/CO was evaluated (where C=concentration of treated sample and CO=concentration of feed sample) and plotted against time to analyze the residual concentration of CrVI.48

Bottom Line: Structure property elucidation was carried out by X-ray diffraction, microscopy, spectroscopy, contact angle measurement, and water uptake studies.The increase in hydrophilicity followed the order: PSf < PSf/TiO2 < PSf/TiO2/CS membranes.The observations reveal 100 % reduction of Cr(VI) to Cr(III) through electrons and protons donated from OH and NH2 groups of the CS layer; the reduced Cr(III) species are adsorbed onto the CS layer via complexation to give chromium-free water.

View Article: PubMed Central - PubMed

Affiliation: Center for Nano and Material Sciences, Jain University Ramanagaram, Bangalore, 562112, India.

ABSTRACT
Herein we present a new approach for the complete removal of Cr(VI) species, through reduction of Cr(VI) to Cr(III), followed by adsorption of Cr(III). Reduction of chromium from water is an important challenge, as Cr(IV) is one of the most toxic substances emitted from industrial processes. Chitosan (CS) thin films were developed on plain polysulfone (PSf) and PSf/TiO2 membrane substrates by a temperature-induced technique using polyvinyl alcohol as a binder. Structure property elucidation was carried out by X-ray diffraction, microscopy, spectroscopy, contact angle measurement, and water uptake studies. The increase in hydrophilicity followed the order: PSf < PSf/TiO2 < PSf/TiO2/CS membranes. Use of this thin-film composite membrane for chromium removal was investigated with regards to the effects of light and pH. The observations reveal 100 % reduction of Cr(VI) to Cr(III) through electrons and protons donated from OH and NH2 groups of the CS layer; the reduced Cr(III) species are adsorbed onto the CS layer via complexation to give chromium-free water.

No MeSH data available.