Advanced Electrode Materials in Electrokinetic Technology for Remediation of Heavy Metal-Contaminated Soil: Recent Progress and Challenges

Heavy metals (HMs) contamination in soil by anthropogenic activities creates human health and environmental issues. The economical and effective extraction of HMs from polluted soil is in high demand for green and sustainable development prospects. Electrokinetic remediation (EKR) is a viable and environmentally friendly technique to remove HMs from contaminated soil. However, the efficiency of EKR is inadequate due to the limited working efficiency of traditional electrode materials. Recently, it has been revealed that advanced electrode materials (Adv-EMs), including nanomaterials, porous materials, and polymers in the 2D EKR, 3D EKR, and auxiliary electrode EKR systems, play a critical role in enhancing removal efficiency, and over the past few years, considerable attention has been paid to them. However, no study is available that summarizes the developments in Adv-EMs in EKR technology. Herein, recent progress and development in designing Adv-EMs are summarized. Specifically, the fundamental mechanisms during the EKR process, along with peculiar examples of Adv-EM synthesis designs with enhanced removal efficiency, are reviewed. Compared with the 2D EKR system, the removal efficiency is much improved using 3D and auxiliary electrodes. This review will provide guidelines for designing Adv-EMs and developing more effective techniques for soil pollution remediation.