Phosphate Removal Using Non-Modified and Magnetically Modified Montmorillonite

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.