EDTA-enhanced electrokinetic extraction of lead

Abstract

Electrokinetic extraction has been demonstrated to be effective in removing lead from pure Georgia kaolinite characterized by a low acid/base buffer capacity and cation exchange capacity. The relatively high removal efficiency is dependent on the low soil pH generated by the electrokinetic process. However, when impurities such as iron oxides are present, electrokinetics alone may not be effective in the extraction of lead due to the higher acid/base buffer capacity and cation exchange capacity of the soil. In this study, the effects of ethylenediaminetetraacetate (EDTA) on enhancing electrokinetic extraction of lead from a natural kaolinite containing approximately 4.3% iron oxides as Fe2O3 were examined. Interactions between lead and soil at different pH values were evaluated by batch tests. Results of the study show that approximately 90% of the lead spiked uniformly into the soil can be migrated toward the anode and accumulated within about 15% of soil for easier removal. ©ASCE.