Pulsed Electrokinetic Decontamination of Agricultural Lands around Abandoned Mines Contaminated with Heavy Metals

Abstract

The feasibility of pulsed electrokinetic remediation under laboratory conditions was investigated using soil samples from contaminated agricultural land around an abandoned area. The major contaminants of the soil were zinc and cadmium. Sequential extraction showed that most heavy metals existed as strongly bound residual fractions, meaning that they were very difficult to remove. Based upon the overall removal of the cadmium and zinc, pulsed electrokinetic has an advantage over normal electrokinetics, and the electromigration was superior to the electroosmotic flow in this study. Catholyte circulation of 0.1N HNO3 in the cathode chamber enhanced the overall removal of heavy metals. The electric energy expenditure for pulsed electrokinetics was half of that for normal electrokinetics under identical conditions yet still had similar removal efficiency. Therefore, pulsed electrokinetics significantly affects energy consumption in a beneficial way. These results suggest that enhanced pulse eletrokinetic remediation is a cost-effective and economical technique.