Synthesis of metal ion loaded silica gel/chitosan biocomposite and its fluoride uptake studies from water

In this study, novel sorbents, silica gel/chitosan (SGCS) and cerium loaded silica gel/chitosan (Ce-SGCS) composites have been synthesized and their application toward fluoride removal from aqueous solution was discussed under batch equilibrium mode. The synthesized sorbents were characterized using FT-IR, SEM with EDAX and XRD studies. At room temperature, Ce-SGCS has a maximum DC of 4821 mgF−/kg, while for SGCS, the DC was 3470 mgF−/kg only in the optimum contact time of 30 min. Thermodynamic studies revealed that the sorption of fluoride on Ce-SGCS composite is endothermic and spontaneous in nature. For the kinetic studies, the pseudo-second order model could explain the kinetic behavior of fluoride adsorption onto Ce-SGCS composite satisfactorily with a good correlation coefficient than the pseudo-first order model. Field studies were carried out with the fluoride containing water sample collected from a fluoride-endemic area in order to test the suitability of the sorbent at field conditions.