title: Preparation and Characterization of Chitosan Thin Films on Mixed-Matrix Membranes for Complete Removal of Chromium.
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.
authors.affiliation: Center for Nano and Material Sciences, Jain University Ramanagaram, Bangalore, 562112, India.
authors.forename: Vignesh
authors.initials: V
authors.lastname: Nayak
authors.affiliation: Center for Nano and Material Sciences, Jain University Ramanagaram, Bangalore, 562112, India.
authors.forename: Mannekote Shivanna
authors.initials: MS
authors.lastname: Jyothi
authors.affiliation: Center for Nano and Material Sciences, Jain University Ramanagaram, Bangalore, 562112, India.
authors.forename: R Geetha
authors.initials: RG
authors.lastname: Balakrishna
authors.affiliation: Center for Nano and Material Sciences, Jain University Ramanagaram, Bangalore, 562112, India.
authors.forename: Mahesh
authors.initials: M
authors.lastname: Padaki
authors.affiliation: Advanced Membrane Research Centre (AMTEC), Universiti Teknologi Malaysia, UTM Skudai 81310, Johor, Malaysia.
authors.forename: Ahmad Fauzi
authors.initials: AF
authors.lastname: Ismail
keywords: chitosan; chromium; composite membranes; hydrophilicity; reduction