Zirconium-treated fine red mud impregnated in Zn-alginate beads as adsorbent in removal of phosphate from water

Abstract

Zirconium-treated fine red mud impregnated in Zn-alginate beads (ZRMAB) are investigated for their adsorption nature towards phosphate from water by varying various physico-chemical parameters such as pH, time of equilibration, sorbent dosage, initial concentration of phosphate, presence of co-anions and temperature. The extraction conditions are optimized for the maximum removal of phosphate and the sorption ability is found to be 13.64 mg/g of the adsorbent. Substantial amounts of phosphate are removed even after ten times of regeneration of the adsorbent. Repetitive use of the same adsorbent completely removes phosphate from water. Surface morphological studies using XRD, FTIR, FESEM and EDX confirm the phosphate is onto the surface of the adsorbent. Adsorption isotherms and kinetic of sorption are analyzed and thermodynamic studies are made. The procedure developed is successfully applied to the removal of phosphate from polluted ground water samples.