Electrokinetic remediation: Past experience and future roadmap for sustainable remediation of metal-contaminated soils

Soil pollution due to heavy metals has become a serious environmental concern in the past decade, adversely affecting soil conditions and global food security. Due to this, considerable attention has been given to developing suitable remediation technologies, particularly for heavy metals. Among them, Electrokinetic Remediation (EKR) is a promising developing technique due to its great efficiency for fine-grained soils. The use of an electric field to remove contaminants from soil is effective on a wide range of matrices irrespective of the heterogeneity. In this context, the present study provides a detailed discussion on the design and operational considerations of EKR, mainly, power, electrode, and electrolyte characteristics. The major limitations of EKR, innovative modifications of EKR operations to overcome the limitations, and EKR-integrated technologies have been addressed. The optimization of regulating parameters ensures maximum efficiency towards removal of contaminants at minimum cost of treatment, thus, highlighting the engineering aspect of electrokinetics at field scale. The sustainability concerns arising from EKR and its possible alternative solutions have been discussed, to provide useful information and prospects to researchers in the field.