Kinetic and equilibrium studies on fluoride removal by zirconium (IV): Impregnated groundnut shell carbon

Abstract

The carbonized ground nut shell (GNSC) was impregnated with zirconium oxy chloride, and tested to determine its capacity and kinetics for fluoride adsorption from aqueous solutions. The analysis of the isotherm equilibrium data using the Langmuir, Freundlich and Redlich-Peterson equations by linear methods showed that the data fitted better with Freundlich model than the other two. Thermodynamic studies revealed that the spontaneous nature of fluoride adsorption with increase of entropy and an endothermic process. The kinetic data obtained for fluoride adsorption on zirconium impregnated ground nut shell carbon (ZIGNSC) obeyed the pseudo-second order equation. X-ray diffraction (XRD) studies confirmed the deposition of fluoride on material and Fourier transform infrared (FTIR) studies also showed the involvement of adsorbate on the adsorbent surface in the adsorption interaction. The ZIGNSC provides a cost effective material to the defluoridation problem in the developing countries by its great potential application in the fluoride removal from water.