A critical review on soil remediation using electrokinetic-enhanced permeable reactive barriers: Challenges and enhancements

Contaminated soil poses a critical threat to ecosystems, affecting their components in various detrimental ways. Among the methods for addressing this issue, the combination of electrokinetic remediation and permeable reactive barrier (EKR-PRB) is particularly effective in low-permeability soils. This approach stands out due to its scalability, environmental benefits, cost-efficiency, and flexibility in application. The efficacy of EKR-PRB is significantly influenced by the choice of reactive materials. This paper provided beneficial insights into EKR-PRB, highlighting their fundamental mechanisms, definitions, and principles. It also comprehensively reviewed reactive materials such as activated carbon (AC), zeolite, zero-valent iron (ZVI), nanoscale zero-valent iron (nZVI), and novel materials, exploring the limitations and challenges associated with these materials. This research focused on evaluating the effectiveness of permeable reactive barrier (PRB) by analyzing their durability, mechanisms of contaminant removal, and structural design within the context of electrokinetic remediation (EKR). Five installation configurations were assessed to determine optimal placement for different pollutant types, with specific setups enhancing removal efficiency significantly. Cost and scalability were analyzed further, revealing that while EKR-PRB are promising for various low-permeability soils, challenges in engineering applications remain due to soil heterogeneity, changes in pH, and limited electroosmotic flow. Enhanced removal efficiency and cost reduction potential highlight EKR-PRB as a viable remediation approach, though further research is necessary for large-scale applications.