Simultaneous removal of hexavalent chromium and COD from industrial wastewater by bipolar electrocoagulation

• Hexavalent Cr and COD were removed from wastewater by electrocoagulation.
• 100% Cr and 95.95% COD was removed after 30-min sequencing process with 200 A/m2.
• Simultaneous 99% Cr and 95 % COD removal only requires 22.07 kWh/kg direct energy.
• The process shows high removal capacity and good selectivity for Cr.

The purpose of this study is to remove hexavalent chromium and COD from wastewater by electrocoagulation. The experiments were carried out in an electrochemical reactor using iron sacrificial electrode. Operating parameters such as current density (100, 150, 200 A/m2), pH of the effluent, number of electrodes and their materials were studied. The optimal operating conditions were determined and applied to the process. The results show that this process of removal can reduce chromium (VI) into chromium (III) with an output of 100% and 95.95% of COD in a relatively short reaction time and at low cost.