Electrokinetic remediation of metal-contaminated field soil

This study evaluates the electrokinetic remediation of a low permeability field soil contaminated with heavy metals. The soil was contaminated with a wide range of heavy metals; but, in order to simulate the actual source zone contamination, the soil was also spiked with lead and mercury at 1000 mg/Kg each. Four bench-scale electrokinetic experiments were conducted at a voltage gradient of 2.0 VDC/cm and a hydraulic gradient of 1.4 using four different extracting solutions, namely 0.2 M ethylenediamine tetra acetic acid (EDTA), 0.2 M diethylene triamine penta acetic acid (DTPA), 0.2 M potassium iodide (KI), and 10% hydroxypropyl-beta-cyclodextrin (HPCD). EDTA and KI were found to be efficient in the removal of lead and mercury, respectively. On the mass-efficiency basis, the EDTA-enhanced system is found to be more effective for the simultaneous removal of a variety of metals, while KI was found to be effective for the selective removal of mercury from the field soil.