Removal of Heavy Metals from Groundwater by Bipolar Electrolysis

Abstract

Bipolar electrolysis is a technique in which cathode and anode of an electrolysis cell are separated by a bipolar electrode, creating a cathode and an anode cell. Both cells are divided up by membranes, which yields four distinct compartments. By an appropriate choice of the electric current, the type of membranes and electrodes, the electrochemical conditions in each of the four compartments can be set. In this way metals such as Cu, Cd, Zn, Co, Pb, Fe and Ni can be precipitated as hydroxides. Mercury, which has a soluble hydroxide, can instead be precipitated as a carbonate. On the other hand, metals such as As can be precipitated under the form of oxide or arseniate at low pH and relatively low electrochemical potential.