Fluoride removal from water by a granular Fe-La complex hydroxide

A granular Fe-La complex hydroxide adsorbent has been characterized by measurement of specific surface area and pore distribution,and phase analysis.The granular Fe-La complex hydroxide was a microporous amorphous material with a specific surface area of 103.3m2/g.Batch adsorption of fluoride onto the adsorbent was studied,including measuring adsorption rates and adsorption isotherms and the effects of pH and co-existing ions were investigated.Batch tests showed that the adsorption rate fitted a pseudo-second-order kinetics equation,and the adsorption of fluoride was affected by both intraparticle diffusion and surface adsorption.The adsorption isotherm data were in accordance with the Freundlich model,and the adsorption capacity reached 30 mg/g when the equilibrium concentration was 35 mg/L.The optimal adsorption pH was 4,and the presence of HPO2-4 had a significant adverse effect on fluoride adsorption capacity.