Phosphate removal using non-modified and magnetically modified montmorillonite

Abstract

Phosphate sorption on sodium montmorillonite and its magnetically modified (using iron oxide) form was studied. The chemical composition and specific surface area of both non-magnetic and magnetically modified montmorillonite were determined. The effect of sorbent dose in solution, sorption efficiency and adsorption equilibrium in a range of phosphate concentrations 1-1000 mg P/L were evaluated. Model solutions of wastewater were prepared using Na3PO4. Phosphate concentrations were determined by UV/VIS. The results show that efficiency increased with increasing amount of sorbent and that it exceeded 80% when 1 g of sorbent was introduced in 50 ml of solution. Obtained experimental equilibrium data were fitted by the Langmuir and Freundlich adsorption isotherms using the linear and non-linear regression. Based on the calculated coefficient of determination, the Langmuir adsorption isotherms determined by non-linear regression were specified. Presence of magnetic iron oxides does not affect the adsorption capacity of sorbents while it allows the magnetic separation of the used sorbent after its application.