Preliminary Laboratory Assessment of the Removal of Heavy Metals from Metal Plating Wastewater by Electrocoagulation

Abstract

The main aim of this study was the removal of heavy metal ions, namely aluminium (Al3+), chromium (Cr3+), zinc (Zn+2), lead (Pb2+) and arsenic (As3+) from metal plating wastewater using electrocoagulation (EC) technique. The Fe–Fe and Fe-Cu electrode pair configuration was used in the reactor. The influence of electrode material, EC time and wastewater pH on removal performance was investigated. The results showed that the heavy metal removal efficiency was higher when using the Fe-Cu electrode pair. Over 90% of heavy metal ions (Cr3+, Zn+2, Pb2+ and As3+) were removed efficiently by conducting the EC treatment at current density (CD) of 12.6 mA/cm2, pH of 6.2 and EC time of 30 min. These operating conditions led to specific energy consumption and specific amount of dissolved electrodes of around 20 kWh/m3 and 0.87 kg/m3, respectively. The kinetic study showed that the removal of such heavy metal ions follows pseudo first-order model.