Adsorption Removal of Fluoride from Aqueous Solution by Hydroxy-Iron Pillared Montmorillonite

Abstract

Hydroxy-iron pillared montmorillonite (Fe-Mont) was prepared and characterized, and the fluoride adsorption capacity of Fe-Mont was investigated. Compared to pure montmorillonite (Mont), the interlayer spacing, specific surface area (SSA), surface fractal dimension and isoelectric point (IEP) of Fe-Mont increased. At pH 4.5, the Langmuir adsorption capacity (qmax) for fluoride of Mont and Fe-Mont was 4.23 and 6.92 mg/g, respectively. The adsorption data for fluoride by Fe-Mont could be fitted by Langmuir model (R2 =0.986) and also by Freundlich isotherm (R2 =0.948), and indicating that the monolayer and multilayer adsorption behaviors are simultaneously involved in the fluoride adsorption processes of Fe-Mont.