Adsorption behavior of Cr(VI) onto radiation crosslinked chitosan and its possible application for the treatment of wastewater containing Cr(VI)

Adsorption of Cr(VI) onto crosslinked chitosan synthesized by gamma irradiation in the presence of carbontetrachloride has been investigated. The adsorption behavior of crosslinked chitosan (CRC) and its hydrolysis product (CRCH) has been compared with native chitosan. The maximum adsorption of Cr(VI) on crosslinked chitosan occurs at pH 3. The results obtained from equilibrium adsorption studies are fitted in various adsorption models such as Langmuir, Freundlich and Dubinin-Radushkevich (D-R) and the model parameters have been evaluated. Various thermodynamic parameters like H-0, S-0 and G(0) for adsorption of Cr(VI) onto crosslinked chitosan have been estimated. The performance of crosslinked chitosan (CRC and CRCH) under flow conditions have also been studied and the results indicates that radiation crosslinked chitosan can be effectively used for treating wastewater containing Cr(VI). The most important aspect of using crosslinked chitosan for treating the wastewater containing Cr(VI) is that after the Cr(VI) is loaded; the column can be easily regenerated and efficiently reused. (C) 2005 Elsevier B.V. All rights reserved.