Magnetic removal of phosphate from wastewater using schwertmannite

Abstract

A magnetic filtration has firstly been applied to the phosphate removal from wastewater by using schwertmannite, which is ferric oxyhydroxide sulfate with high capacity of phosphate adsorption. High efficiency of phosphate removal without using magnetic seeding was obtained at magnetic intensities of around 1 Tesla, which means no necessity to use a superconducting magnet. The kinetics data of phosphate adsorption have been found to be fitted well with a pseudo-second-order model and adsorption equilibrium data have been explained by the Langmuir isotherm. The effect of pH on the phosphate adsorption in this process was characterized by zeta potential measurement. It is proposed that ligand exchange is a dominant mechanism responsible for phosphate adsorption on schwertmannite. © 2006 The Japan Institute of Metals.