Sorption of Fluoride Ions from Aqueous Solutions and Well Drinking Water by Thermally Treated Hydrotalcite

Abstract

Fluoride is a naturally occurring element in many water supplies, and it may cause fluorosis. The hydrotalcite was synthesized and characterized before and after the retention of fluoride ions by x-ray diffraction, electron microscopy, and IR. The thermally treated hydrotalcite was evaluated for the sorption of fluoride ions from aqueous solutions at pH 5, 7, and 9 and well water. It was found that the retention of fluoride ions by the material was 80% or higher. The Kd values show that the best conditions for the sorption of F⁻ ions from the solutions is at pH 5, and they show as well that the physicochemical properties affect the uptake process.

Keywords:

• Hydrotalcite
• Retention
• Fluoride ions

Acknowledgments

The authors thank financial support from CONACYT (Project 35322-E) and Departamento de Análisis Químicos del Instituto Nacional de Investigaciones Nucleares for the analysis of Na, Mg, Al and in the hydrotalcite and the colorimetric fluoride determinations and V. Martínez-Miranda for her suggestions.