Chromium(VI) removal from industrial wastewater using hydrogen peroxide assisted electrocoagulation

In this study, removal of hexavalent chromium, Cr(VI), from real industrial wastewater using hydrogen peroxide (H2O2) assisted electrocoagulation was investigated. The material for anode and cathode was iron. The impact of operating parameters including pH, current density and the H2O2 concentration on removal efficiency and energy consumption was explored in detail. The results showed that the chrome removal efficiency improved at acidic conditions (lower pH) and also with the increase of current density whereas the addition of H2O2 at any concentration decreased the removal efficiency. An initial Cr(VI) concentration of 518.9 mg/L was reduced to 0.523 mg/L after 60 min which was equal to overall removal efficiency of 99.92% when current density of 10 mA/cm2 and pH 3.0 were applied while no H2O2 was added. At these conditions, 1.61 kWh/m3 energy was consumed and the estimated operational cost was 0.803 USD/m3of wastewater. Our findings showed that the electrocoagulation was an effective treatment method for chromium rich wastewater but the hydrogen peroxide did not improve the outcomes.