Electrokinetics: Electric Current Technologies
Electrokinetics relies upon application of a low-intensity direct current through the soil between ceramic electrodes that are divided into a cathode array and an anode array. This mobilizes charged species, causing ions and water to move toward the electrodes. Metal ions, ammonium ions, and positively charged organic compounds move toward the cathode. Anions such as chloride, cyanide, fluoride, nitrate, and negatively charged organic compounds move toward the anode. Removal of contaminants at the electrode may be accomplished by several means, among which are: electroplating at the electrode; precipitation or co-precipitation at the electrode; pumping of water near the electrode; or complexing with ion exchange resins.
This report prepared by the Ground Water Remediation Technologies Analysis Center (GWRTAC) provides an introduction to the general principles of the electrokinetic technology, its criteria for application, performance, advantages and limitations to use, selected commercial applications, and references.
4.5 Electrokinetic Separation (In Situ Soil Remediation Technology)
In Remediation Technologies Screening Matrix and Reference Guide, Version 4.0. Federal Remediation Technologies Roundtable.
The Center for Public Environmental Oversight (CPEO), Washington, DC.
Electrokinetic Remediation and Its Combined Technologies for Removal of Organic Pollutants from Contaminated Soils
Huang, D., Q. Xu, J. Cheng, X. Lu, and H. Zhang.
International Journal of Electrochemical Science, Vol 7, 4528-4544, 2012
This paper reviews six types of electrokinetic (EK) remediation applications to soil contaminated with organic compounds: the direct EK technique, EK combined with Fenton's reagent, EK combined with surfactants or co-solvents, EK combined with bioremediation, EK combined with ultrasonic remediation, and the technology known as Lasagna. Basic principles, characteristics, application areas, research developments, and prospects are described for these six techniques. The technology combinations, contaminant types, soil types, and reported removal efficiencies are compiled into a table with references.
Electrokinetic Remediation of Organochlorines in Soil: Enhancement Techniques and Integration with Other Remediation Technologies
Gomes, H.I., C. Dias-Ferreira, and A.B. Ribeiro.
This review summarizes strategies that have been tested to improve electrokinetic remediation effectiveness for organochlorines in soil, including techniques to solubilize contaminants (surfactants, cyclodextrins), control soil pH, and couple electrokinetics with other remediation techniques (zero-valent iron, phytoremediation, permeable reactive barriers, oxidation/reduction, ultrasonication, biodegradation). Removal efficiencies reported in real contaminated soils are much lower than the ones obtained with spiked kaolinite, indicating the influence of factors such as contaminant weathering and adsorption to soil particles.