Electrokinetically Enhanced Remediation of Hydrophobic Organic Compounds in Soils: A Review

Electrokinetically enhanced remediation is an innovative technology that has the potential to remediate hydrophobic organic compound (HOC) contamination in soils and groundwater. A surfactant/cosolvent is used to increase HOC desorption and solubilization, and an applied electric potential facilitates contaminant transport primarily by electroosmosis and/or electrophoresis. Electroosmotic flow generally improves soil–solution–contaminant interaction, especially in zones of high organic content and/or low hydraulic conductivity. The electrokinetically enhanced remediation process is fairly simple to implement and operate, but the fundamental reactions that govern the remediation method are complex. An adequate knowledge of the contaminant transport mechanisms and the physical, chemical, and electrochemical processes is essential in order to optimize system performance. This article reviews previous research efforts on HOC remediation and the use of in situ flushing and electrokinetics for organic contaminants. In addition, to gain a better understanding of the individual components and the complexities of the electrokinetically enhanced in situ flushing process, this article presents background information on HOCs and surfactants/cosolvents, as well as the basic parameters that affect the performance of in situ flushing and electrokinetic technologies. Since the success or failure of electrokinetic remediation for HOC pollutants in low permeability soils largely depends on electroosmotic advection and/or electrophoresis, the discussion concerning electrokinetics focuses on these contaminant transport mechanisms.

KEYWORDS:

• cosolvents
• electrokinetics
• electroosmosis
• flushing, PAHs
• remediation
• soils
• surfactants

Acknowledgments

This study was partly supported by the National Science Foundation Grant, CMS number 0100073. The financial support of this agency is gratefully acknowledged.