Electrochemical techniques for the removal and recovery of heavy and precious metals from waste sources

The treatment of industrial wastewater containing heavy and precious metals is becoming increasingly important in response to the dual drivers of environmental impact and recovered value. Due to the intrinsic toxicity of these metals, users and producers across many industrial sectors are being affected by strict legislation. The electrochemical technique is unique in its ability to recover elemental metal directly from aqueous solution without the addition of reagents, by the direct use of electricity, i.e. the electron is the reagent. The development of a new, novel electrochemical cell is described. The approach is based upon the use of porous electrodes with a very high surface area available for metal deposition. Using this technique, very low concentrations of less than 1 mg l(-1) can be achieved.