Simultaneous Removal of Hexavalent Chromium and Nitrate from Wastewater using Electrocoagulation Method

Abstract

The simultaneous removal of hexavalent chromium and nitrate ions from an aqueous solution by electrocoagulation (EC) using aluminum as the anode was investigated.The model wastewater was fabricated in 200 mg L of basic chromium and 500 mg L of nitrate.Different parameters, such as time, applied current and pH, were examined.Moreover, the effects of the EC process on the evolution of pH and ORP and the amount of aluminum released during the EC process were investigated.The removal of both Cr (VI) and nitrate increased with an increase in the current intensity, and the EC process induced a pH increase over a period of 120 min.It is notable that the minimum Cr (VI) removal efficiency was 45% for a current of 0.02 A. In the case of nitrate, it was demonstrated that the nitrate reached zero discharge between 0.5 and 1.0 A. For both ions, the removal efficiency was over 90%.The results showed that, with increasing pH, nitrate and chromium removal increased.The results also show that, with an increase in time and current intensity, the rate of aluminum release also increased.Additionally, the ORP decreased from -257 to -740 mV as the current increased from 0.02 to 1 A, respectively.