title: Photocatalytic aptitude of titanium dioxide impregnated chitosan beads for the reduction of Cr(VI).
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.
authors.affiliation: Department of Chemistry, The Gandhigram Rural Institute - Deemed University, Gandhigram 624 302, Tamil Nadu, India.
authors.forename: M
authors.initials: M
authors.lastname: Hasmath Farzana
authors.affiliation: Department of Chemistry, The Gandhigram Rural Institute - Deemed University, Gandhigram 624 302, Tamil Nadu, India. Electronic address: drs_meena@rediffmail.com.
authors.forename: Sankaran
authors.initials: S
authors.lastname: Meenakshi
mesh_terms: D000327:Adsorption; D002384:Catalysis / Q000187:drug effects / Q000528:radiation effects; D048271:Chitosan / Q000494:pharmacology*; D002857:Chromium / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010084:Oxidation-Reduction / Q000187:drug effects / Q000528:radiation effects; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013997:Time Factors; D014025:Titanium / Q000494:pharmacology*; D014466:Ultraviolet Rays
chemical_list: D007477:Ions; D002857:Chromium; C009495:titanium dioxide; C074702:chromium hexavalent ion; D048271:Chitosan; D014025:Titanium
keywords: Chitosan; Chromium; Langmuir–Hinshelwood mechanism; Photo- reduction