Influence of Electrode Type on the Engineering Properties of Lead Contaminated Soil Subjected to Electro-Kinetic Remediation

Abstract: This study evaluated the effectiveness of electrokinetic remediation (EKR) using aluminium, carbon, and graphite electrodes in improving the environmental and geotechnical properties of lead-contaminated soil. The untreated soil was classified as A-7-6 according to the AASHTO classification system and CL (lean clay) under the Unified Soil Classification System (USCS), indicating a fine-grained soil with moderate plasticity. The results demonstrated that electrokinetic remediation effectively removed lead and other contaminants from the soil. The aluminium electrode achieved the highest PbO removal efficiency of 84.20%, followed by the carbon (82.60%) and graphite (68.80%) electrodes. Significant removal efficiencies were also recorded for Fe₂O₃, Cr₂O₃, SO₃, and K₂O, confirming the effectiveness of the remediation process. Furthermore, the engineering properties of the soil improved following remediation. The liquid limit decreased from 48.0% in the untreated soil to 45.3%, 46.2%, and 41.4% for the aluminium-, carbon-, and graphite-treated soils, respectively, while the plasticity index reduced from 19.8% to 18.8%, 16.7%, and 15.6%. Similarly, the specific gravity increased from 2.41 to 2.57, 2.53, and 2.58, respectively. The findings demonstrate that electrokinetic remediation using aluminium, carbon, and graphite electrodes significantly enhanced both the environmental quality and engineering performance of the lead-contaminated soil, with the aluminium electrode exhibiting the highest lead removal efficiency.