Rapid removal of fluoride from aqueous media using activated dolomite

Abstract

Fluoride is one of the most omnipresent groundwater pollutants. Thus the objective of this paper was to evaluate the efficiency of thermally activated dolomite for the removal of fluoride. An inexpensive and widely available geomaterial, dolomite, was shown to have excellent fluoride removal properties from aqueous media. The batch experiments were performed under static and shaking conditions using thermally activated dolomite powder where equilibrium was reached just within 5 min under shaking conditions with 90.87% fluoride removal. The fluoride removal capacity of the dolomite at pH 7.0 is 243.25 mg g⁻¹ which is in excellent agreement with the theoretically calculated value of 240.21 mg g⁻¹. The uptake of fluoride by the thermally activated dolomite mainly followed an ion-exchange mechanism, pseudo-second order kinetics and the Freundlich isotherm. Scanning electron microscopy with energy dispersive X-ray (SEM-EDX) and X-ray diffraction studies demonstrated the thermally activated dolomite as an excellent material for fluoride removal. The proposed method is quite effective and practical for the defluoridation of drinking as well as waste water in comparison to literature reported methods.