Tin(IV) cross-linked chitosan for the removal of As(III).

Chitosan, a potent amino polysaccharide, has been cross-linked with Sn(IV) chloride. The material was thoroughly characterized using FT-IR, XRD, SEM, EDX, TGA-DTA and BET studies. This Sn(IV) chloride cross-linked chitosan (Sn-Ch) has been exploited for As(III) adsorption. Various parameters like pH, amount of adsorbent, adsorption time etc have been optimized to achieve maximum adsorption efficiency. Under optimum conditions of pH 7.0±0.2, adsorption time of 45min and adsorbent dose 200mg, Sn-Ch was found to have adsorption capacity of 17.10mg/g at 298K. Adsorption of As(III) by Sn-Ch follow non-linear Freundlich isotherm model. The equilibrium studies showed that the experimental data fits well with non-linear pseudo-second-order kinetic model. Adsorption process was found to be exothermic and spontaneous. Column study proves the applicability of Sn-Ch to the larger sample volumes. It was found to be recyclable material and could be regenerated and reused multiple times adding a greener dimension.