Removal of fluorine from water by using the synthetical iron-aluminum hydroxide complexes

Based on the strong affinities of Fe(III) and Al(III) to fluoride, four iron- aluminum hydroxide complexes were synthesized as adsorbents for the fluoride removal. Moreover, the adsorption experiments showed that all iron-aluminum complexes could adsorb aqueous fluoride effectively and with a high capacity. When an fluoride solution of 10 mg/L^-1 was added with anyone of these complexes at pH 5.0-9.0, the fluoride concentration could be decreased to less than 0.01 mg/L^-1, the standard for drinking water set by the World Health Organization. Among these absorbents, the complex with the Fe(III)/Al(III) molar ratio of 0.7:0.3 owned the highest fluoride removal.