Photocatalytic aptitude of titanium dioxide impregnated chitosan beads for the reduction of Cr(VI).

M Hasmath Farzana, Sankaran Meenakshi

Index: Int. J. Biol. Macromol. 72 , 1265-71, (2014)

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Abstract

This article describes the photo-reduction of heavy metal Cr(VI) in aqueous solution using titanium dioxide impregnated chitosan beads (TCB) in the presence of UV irradiation. The synergistic role of TCB results in excellent photocatalytic behavior. The reduction of Cr(VI) by the TCB is mainly due to adsorption coupled photocatalytic reduction mechanism. The characterization of TCB was made by Fourier transform Infrared (FTIR) Spectral studies, Scanning Electron Microscope (SEM), Energy Dispersive Analysis of X-ray (EDAX) and Electron Paramagnetic Resonance (EPR) studies. The kinetics of photo-reduction of Cr(VI) is explained on the basis of Langmuir-Hinshelwood mechanism. A comparative study on the percentage removal of chromium using chitosan (CS), titanium dioxide (TiO2) and titanium dioxide impregnated chitosan beads (TCB) in the presence of UV irradiation at 60 min of contact time have been found to be 19.4%, 54.8% and 91.4% respectively. Effects of experimental parameters such as irradiation time, dose, pH, initial concentration, and co-ions were optimized for Cr(VI) removal. Suitability of TCB at field condition was tested with a sample taken from a nearby industrial area.Copyright © 2014 Elsevier B.V. All rights reserved.