Hydrothermal synthesis of magnetic iron oxide encrusted hydrocalumite-chitosan composite for defluoridation studies.

A magnetic adsorbent namely magnetic iron oxide encrusted hydrocalumite-chitosan (Fe3O4@HCCS) composite was prepared by the fabrication of magnetic iron oxide (Fe3O4) particles on hydrocalumite-chitosan (HCCS) composite for fluoride sorption studies in batch mode. The prepared magnetic Fe3O4@HCCS composite possesses an enhanced defluoridation capacity (DC) of 6.8mg/g compared to hydrocalumite (HC) which possesses the DC of 2.4mg/g. The various physico-chemical parameters such as contact time, pH, co-existing anions, initial fluoride concentration and temperature were optimized for the maximum fluoride removal. The structural changes of the sorbent, before and after fluoride sorption were studied using FTIR and SEM with EDAX techniques. The equilibrium data was well modeled by Freundlich and Langmuir isotherms. The thermodynamic parameters revealed the feasibility, spontaneity and endothermic nature of fluoride sorption. The field performance and efficiency of Fe3O4@HCCS composite was examined with the waste-water sample collected from a fluoride endemic area of Dindigul district, Tamilnadu, India using standard protocols.