Assimilation of chitin with tin for defluoridation of water

Abstract

Chitin, a natural amino polysaccharide, has been incorporated with Sn(IV) for effective adsorption of fluoride from water. The impregnation of Sn(IV) on chitin was carried out using a microwave assisted technique. The material was thoroughly characterized using FTIR, SEM, EDX and XRD. The increase in surface area and pore volume as revealed by BET studies and enhanced thermal stability TGA-DTA studies have proved it to be a better adsorbent compared to chitin. This tin-impregnated chitin (SnC) has been exploited for its defluoridation properties. Optimum working conditions include pH 4.0, an adsorbent dose of 100 mg and a contact time of 45 minutes. Under optimum conditions, SnC was found to have an adsorption capacity of 14.77 mg g⁻¹. Equilibrium studies show that the data fits well with the Freundlich isotherm model. Thermodynamics and kinetics parameters have been evaluated. The material has been applied for the defluoridation of real water samples, resulting in 95.6% fluoride removal in a single run. SnC was found to be a recyclable material and can be regenerated and reused multiple times adding a greener dimension.