Evaluating the Effectiveness of Modified Pumice in Fluoride Removal from Water

Abstract

An excess amount of fluoride ions in drinking water has been known to cause adverse effects on human health. The fluoride removal from synthetic water by modified pumice was studied at batch experiments. The chemical activation process was achieved chemically with FeCl₃, Al₂(SO₄)₃ and HDTMA-Br. The effect of pH, contact time, fluoride concentration and adsorbent dose on fluoride sequestration was investigated. The results showed that 0.3M HDTMA-Br had best function for pumice modification in fluoride removal. Kinetic data showed that fluoride adsorption was rapid in the beginning and maximum uptake occurred in 0.5 h and equilibrium reached within 3 h. The maximum fluoride adsorption was obtained at pH = 7. Also, with increasing fluoride initial concentration and decreasing pumice dose, the fluoride removal efficiency decreased. The obtained results in this study were matched with Freundlich isotherm and pseudo second order kinetic. The maximum adsorption capacity (qm) and rate constant were found 0.29 (mg/g) and 0.13 (mg/g min), respectively.