Removal of fluoride ions from aqueous solution by the calcination product of Mg-Al-Fe hydrotalcite-like compound

The calcination product of Mg-Al-Fe hydrotalcite compound at 500 degrees C (HTlc500) was used as the adsorbent to remove fluoride ions from aqueous solution, while the Mg-Al-Fe hydrotalcite compound was synthesized by co-precipitation method. The hydrotalcite-like compounds (HTlcs) were characterized by XRD, FT-IR, TG-DTA, SEM, TEM, BET and pH(PZC) analysis. The characteristics showed that the HTlc500 had a porous structure, while the Mg-Al-Fe hydrotalcite has a memory effect. Batch adsorption studies were conducted under various equilibration conditions, such as different pH, calcined temperature, adsorbent dose, co-existing anions, contact time and initial fluoride ions concentrations. It was found that the HTlc500 had the largest adsorption capacity of 14 mg/g at pH 6 with adsorbent dose of 0.2 g/L and the adsorption data were well described by the Langmuir isotherm model and the pseudo-first order kinetic model. According to these studies, the HTlc500 has potential application in fluoride ions removal field. (C) 2010 Elsevier B.V. All rights reserved.