ELECTROCHEMICAL TECHNOLOGY FOR REMOVING HEAVY METALS PRESENT IN SYNTHETIC PRODUCED WATER

摘要

The performance of an electrocoagulation (EC) system with aluminium and iron electrodes for removing heavy metal ions (Cd~(2+), Cu~(2+), Cr~(3+), Sr~(2+) and Zn~(2+)) 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. Cd~(2+), Cu~(2+), Sr~(2+) and Zn~(2+) showed similar removal rates, under similar conditions, indicating a uniform electrochemical behavior. The study gave indications on the removal mechanisms of the investigated metals. Cd~(2+), Cu~(2+) and Zn~(2+) ions are hydro-lyzed and co-precipitated as hydroxides. Cr~(4+), was proposed to be reduced first to Cr~(3+) 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.