Removal of toxic fluoride ion from water using low cost ceramic nodules prepared from some locally available raw materials of Assam, India

Abstract

Globally in recent years, the availability of safe drinking water to each and everyone is a major developmental thrust. However, in many parts of the world one major problem in this thrust is the presence of fluoride ion in water beyond the permissible limit prescribed by WHO (>1.5ppm), causing multiple health related issues. From the water affordability point of view removal of such excess fluoride through low cost methods is extremely important. In the present work we have prepared low cost ceramic nodules from locally available raw materials of Assam, India and studied their potential applications for removal of toxic fluoride ion. The physical parameters of the nodules like mechanical strength, porosity, bulk density, apparent density and water absorption were determined. Defluoridation from fluoride spiked water and real life ground water were carried out in batch mode and the effects of adsorbent dose, pH, contact time, temperature, initial concentration of the adsorbate and the effect of coexisting ions on sorption was studied. Sorption isotherms and sorption kinetics was studied along with determination of ΔHo, ΔSo and ΔGo. Freundlich model was the best fitted model on the basis of highest adjusted R2 and the adsorption process followed second order kinetics.