Trapping heavy metals by using calcium hydroxyapatite and dielectrophoresis

We propose a novel technique for the removal of heavy metal waste from contaminated water. Our method consists in using dielectrophoresis (DEP) to trap hydroxyapatite (HAP) particles of 1 mu m size in water after they have adsorbed heavy metal (Pb, Zn, Cu, Co and Cr). Although HAP can adsorb heavy metals in water and as such offers great promise as a waste-cleaning tool [1-3], one of the current challenges is the elficient removal of the HAP particles once they have adsorbed the heavy metals. We show in this paper that DEP can be used to concentrate such particles in certain regions, thus rendering the rest of the solution volume nearly free of contaminated particles. We present here both experimental and numerical results for suspensions at low concentrations. (c) 2006 Elsevier B.V. All rights reserved.