Fluoride adsorption from aqueous solution by a hybrid thorium phosphate composite

Contamination of drinking water due to fluoride is a severe health hazard. Present investigation aims to remove fluoride by polycinnamamide thorium (IV) phosphate. Polycinnamamide thorium (IV) phosphate was synthesized by co-precipitation method and was characterized by SEM and FTIR. Dependence of adsorption on adsorbent dose, pH of the solution, contact time, temperature had been studied to achieve the optimum condition. The removal of fluoride was 87.6% under optimum conditions. Adsorption kinetic study revealed that the adsorption process followed first order kinetics. Adsorption data were fitted to linearly transformed Langmuir isotherm with correlation coefficient (R2) > 0.99. Adsorption capacity calculated from Langmuir isotherm was found to be 4.749 mg/g. Thermodynamic parameters were also calculated to study the effect of temperature on removal process. In order to understand the adsorption type, equilibrium data were tested with Dubinin–Radushkevich isotherm.