Kinetic and thermodynamic studies on adsorption of fluoride by dolomite

Abstract

Batch adsorption studies were carried out to determine the effect of adsorbent dose, initial adsorbent concentration and temperature on the adsorption of fluoride by naturally occurring dolomite. The adsorption of fluoride was found to depend on temperature and concentration. The adsorption process followed first-order kinetics. The mechanism of adsorption obeyed Langmuir adsorption isotherm indicating an unimolecular layer pattern. Dolomite possesses considerable defluoridation efficiency at neutral <i style="mso-bidi-font-style:normal">p</i>H and hence can be an effective defluoridating material. Thermodynamic studies revealed that the adsorption or fluoride by dolomite is an endothermic process, showing increase in sorption at higher temperature. Also, negative values of <i>∆G</i>^{<span style="mso-bidi-font-style:italic">º</span>}<span style="mso-bidi-font-style:italic"> indicate the spontaneity of the sorption process.

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