Critical Review of Electro-kinetic Remediation of Contaminated Soils and Sediments: Mechanisms, Performances and Technologies

Abstract

Remediation of contaminated soil and sediment is important for improving the eco-environmental quality. Electro-kinetic remediation (EKR) is an environmentally friendly technology to migrate and remove pollutants from the soil and sediment matrix. This paper analyses the mechanism and performance of EKR of heavy metals, organic pollutants, and compound pollutants. Moreover, the effect of optimizing individual EKR through soil and sediment pre-treatment (adding acid/oxidant/co-solvent/surfactant, stirring, heating, etc.), electrode optimization (exchange electrode, anode approximation, electrode matrix, etc.), and applying multi-technology combination (electro-kinetic permeable reaction barrier/Fenton/ion, exchange membrane/ultrasonic/electrolyte enhancement, etc.) was evaluated. Factors including incomplete separation of pollutants, variation in physico-chemical properties and microstructure of soil/sediment, and difficulties in in situ practice have restrained the field application of EKR. To solve the above technical challenge, an integrated EKR technology based on pollutant in situ separation, followed by separated contaminant treatment, and subsequent valuable elements recovery is proposed.

Revealing underlying mechanisms affecting electrokinetic remediation of an artificially Cu- and Pb-contaminated loess using the external regulatory system with adsorbent

“…Material selection of the electrode itself is crucial in mitigating the effect of electrode polarization, and it has focused on EC and electrochemical activity. In light of this, higher current density and corrosion resistance were deemed as the main criteria for determining an appropriate material of electrodes applied to the EK remediation (Han et al, 2021;Wang et al, 2021). There are two types of electrodes present in this study: graphite and EKG (Wen et al, 2021).…”

Advance in remediated of heavy metals by soil microbial fuel cells: Mechanism and application

“…For the convenience of the ensuing presentation, copper is taken as an example of the target pollutant ( Figure 1F ). Electromigration is determined by the valence of ions as well as the external electric field and is regarded as the main driving force in EKR for heavy metal movement ( Acar et al, 1995 ; Han et al, 2021 ). For soil MFCs, anode potential is primarily controlled by electroactive bacteria and the reduced species on the electrode.…”

Comprehensive study of electrokinetic-assisted phytoextraction of metals from mine tailings by applying direct and alternate current

“…When direct electric current (DC) is applied to a soil, the electrolysis of water, generating acid and basic fronts at the anode and cathode, respectively, along with electrokinetic phenomena, i.e. mainly electroosmosis and electromigration, increase the mobility and transport of metal ions through the soil [9][10][11][12]. Therefore, electrokinetic-assisted phytoremediation (EKPH) emerges as an interesting alternative to chelating agents to increase metal availability and shorten remediation times.…”