Synthesis of nanocomposite of cryptocrystalline magnesite-bentonite clay and its application for phosphate removal from municipal effluents

Abstract

In the present study, nanocomposite of cryptocrystalline magnesite-bentonite clay was used as a novel technology for removal of phosphates from municipal effluents. Vibratory ball miller was used for fabrication of the composite. Removal of phosphate from aqueous solution was achieved using batch experimental procedures. Parameters optimized include time, dosage, concentration and pH. Optimization experiment revealed that 30 mins of shaking time, 1 g of composite, 100 mg L-1 of phosphate, 1: 100 S/L ratios, 250 rpm, pH 10 and room temperature are the optimum conditions for removal of phosphate. Adsorption data fitted well to Langmuir adsorption isotherm than Freundlich adsorption isotherms hence confirming monolayer adsorption. Adsorption kinetics data fitted well to pseudo second-order kinetics than first-order-kinetics hence suggesting chemisorption. This comparative study showed better adsorption of the composite as compared to conventional methods of phosphate removal. The results suggest that the fabricated composite has the potential in remediation of phosphate contaminated waters.