Electroremediation of Cr(VI) contaminated soils: kinetics and energy efficiency

Experiments have been conducted on Cr(VI) contaminated kaolin to determine the kinetics of electroremediation (ERM) and the associated rate controlling mechanism. ERM experiments of potassium dichromate contaminated kaolin show that approximately 15% chromium was removed in the first 20 h. Thereafter, there was a drastic reduction in the chromium removal rate. After 144 h, only 31% of Cr(VI) was removed from kaolin. Migration of the acid and base fronts leading to acid-base neutralization appears be the rate controlling step in the ERM of chromium. A significant fraction of chromium could not be remediated due to acidic conditions in kaolin. Results also show that the extent of both remediated and adsorbed (unremediated) chromium and power consumption increased with voltage.