Phosphate removal from aqueous solution by Donnan dialysis with anion-exchange membrane

Abstract

The removal of phosphate from aqueous solution by Donnan dialysis with anion-exchange membrane was investigated. The results show that phosphate could be removed from aqueous solution without supplying external high pressure or electrical potential. Under the conditions of influent phosphate of 2.0 mg/L, counterion(Cl−) concentration of 0.1 mol/L, stirring speed of 500 r/min and phase temperature of 298 K, the removal of phosphate achieves 70.0%. Decreasing counterion concentration has little influence on the removal of phosphate, but phosphate amount in anion-exchange membrane increases significantly. With the increase of stirring speed and phase temperature, the removal efficiency of phosphate greatly is improved. Existing forms of phosphate in aqueous solution affected transport of phosphate and only strong acidic pH of feed solution (pH=3.0) decreases the removal of phosphate. Transport of phosphate is also accompanied by change of pH value of feed solution. In consequence, it might be a promise potential process for phosphate advanced wastewater treatment, especially in the area where high salted nature water can be utilized.