EDTA-ENHANCED ELECTROKINETIC EXTRACTION OF LEAD

Electrokinetic extraction has been demonstrated to be effective in rem oving lead from pure Georgia kaolinite characterized by a low acid/bas e buffer capacity and cation exchange capacity. The relatively high re moval efficiency is dependent on the low-soil pH generated by the elec trokinetic process. However, when impurities such as iron oxides are p resent, electrokinetics alone may not be effective in the extraction o f lead due to the higher acid/base buffer capacity and cation exchange capacity of the soil. In this study, the effects of ethylenediaminete traacetate (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 val ues were evaluated by batch tests. Results of the study show that appr oximately 90% of the lead spiked uniformly into the soil can be migrat ed toward the anode and accumulated within about 15% of soil for easie r removal.