Optimizing Enhanced Electrokinetic Method for Lead and Zinc Removal from Zinc Processing Residue Contaminated Soil

Abstract

Remediating soils contaminated with heavy metals is crucial for safeguarding human health, preserving ecosystems, and ensuring sustainable land use. Among the soil remediation technologies, Electrokinetic (EK) as a technique for soil, sediment, and groundwater purification is based on a direct current electric field applied to a contaminated matrix to extract contaminants through a combined mechanism of electroosmosis, electromigration, and electrophoresis. However, the effectiveness of this technique can be affected by the adsorption of contaminants on the soil particle surface and the generated hydrogen and hydroxide ions at the electrodes. In this study, EK technology was applied to remove the heavy metals (Pb, Zn) in real contaminated soil of zinc processing residue. For this purpose, the effects of EDTA, citric acid, nitric acid, and distilled water as electrolytes were investigated. A cylindrical EK reactor (24 cm length) equipped with a DC electric current (maximum value of 24 V) with graphite electrodes was used. It was concluded that pH control removed 33% of Pb and 55% of Zn from the soil section, applying nitric acid and EDTA as electrolytes, respectively. Consequently, a framework for future research on resource recovery and environmental protection has been created by focusing on the use of EK for sustainable resource management.