Electrochemical technology for removing heavy metals present in synthetic produced water

−− The performance of an electrocoagulation (EC) system with aluminium and iron electrodes for removing heavy metal ions (Cd2, Cu2, Cr3, Sr2 and Zn2) present in synthetic produced water on laboratory scale was studied systematically. Experimental parameters such as applied current, flow effluent and sacrificial electrodes were investigated in order to understand their influence on the EC process. Increasing the current density accelerated the electrocoagulation process, but made it less efficient. Cd2, Cu2, Sr2 and Zn2 showed similar removal rates, under similar conditions, indicating a uniform electrochemical behavior. The study gave indications on the removal mechanisms of the investigated metals. Cd2, Cu2 and Zn2 ions are hydrolyzed and co-precipitated as hydroxides. Cr, was proposed to be reduced first to Cr3 at the cathode before precipitating as hydroxide. The process expenditure was estimated and reported showing the viability of this process as a green alternative, obtaining modest costs using Fe electrodes.