Electrocoagulation as a remediation tool for wastewaters containing arsenic

This work shows results of electrocoagulation of solutions containing arsenic. The continuous flow treatment consisted of an electrocoagulation reactor with two parallel iron plates and a sedimentation basin.The results showed that the electrocoagulation process of a 100 mg/L As(V) solution could decrease the arsenic concentration to less than 2 mg/L in the effluent with a current density of 1.2 A/dm2 and a residence time of around 9 min. Liquid flow was 3 L/h, and the DC current was reversed each 2 min.Increasing the current density from 0.8 to 1.2 A/dm2, the Fe3+ and OH− dosages increase too, and thereby favouring the As removal. On the other hand, it seems that increasing the current density beyond a maximum value, the electrocoagulation process would not improve further. This could probably be explained by passivation of the anode.