ADSORPTIVE FLUORIDE REMOVAL FROM AQUEOUS SOLUTION BY USING SAPONIFIED ORANGE PEEL RESIDUE IMMOBILIZED SORBENT

Abstract

Fluoride is a widespread element, which contaminates majority of the water resources in India. Fluoride, beyond its maximum permissible limit (1.5 mg/L) causes various physiological problems of which dental and skeletal fluorosis are noteworthy. This study aims to develop a sorbent, by successfully immobilizing saponified orange peel residue (SOPR) in alginate matrix and applying a 3-step modification procedure to enable F^- sorption from water. Batch equilibrium studies indicate that Langmuir model of isotherm and Pseudo second order rate kinetics were followed with a maximum sorption capacity of 7 mg/g. FTIR studies confirm the involvement of –OH and carbonyl groups in F^- uptake. The morphological changes are evident in SEM micrographs. Hence electrostatic interaction and ion exchange could be the possible mechanisms by which F^- ions are removed from water. Thus the developed sorbent could be used effectively for defluoridation in areas where the F^- concentration exceeds the recommended limit.