Theoretical Basis for the Simulation of Electrokinetic Remediation

• Published in: Remediation Engineering of Contaminated Soils pp. 155 - 171
• Main Authors: Alshawabkeh, Akram N., McGrath, Christian J.
• Format: Book Chapter
• Language: English
• Published: CRC Press 2000
• Edition: 1
• Subjects: Nonextractable Residues; Geochemical Reactions; Electrokinetic Remediation; Effective Diffusion Coefficient; Electroosmotic Advection; Non-extractable Residues; Contaminated Soil; Charge Flux; Electrokinetic Soil Remediation; Mass Flux; Negative Pore Water Pressure; Chromated Copper Arsenates; Hydraulic Conductivity; Electroosmotic Permeability; Electrical Gradients; Hydraulic Head; Aqueous Reactions; Water Electrolysis Reactions; Electroosmotic Flow; Pore Fluid Chemistry; Effective Electrical Conductivity; Electrolysis Reactions; Effective Ionic Mobility; Species Mass Flux; Pore Fluid
• ISBN: 9780824703325; 0824703324
• DOI: 10.1201/9781482289930-6

Electrokinetic soil remediation employs electric currents through electrodes inserted in the contaminated soil to produce an electric field. Ambient or introduced solutes migrate in response to the imposed electric field by electroosmosis and ionic migration. Electroosmosis mobilizes the pore fluid to flush solutes, usually from the anode ( + ve ) toward the cathode ( - ve), while ionic migration effectively separates anionic ( - ve) and cationic (+ve) species, drawing them to the anode and cathode, respectively. This transport, coupled with geochemical reactions such as sorption, precipitation, and dissolution, are the fundamental mechanisms of electrokinetic remediation. Contaminant extraction and removal are accomplished by electrodeposition, precipitation, or ion exchange, either at the electrodes or in an external extraction system. The major advantages of the technology include: (a) it can be implemented in situ with minimal disruption, (b) it is well suited for fine-grained, heterogeneous media, where other techniques such as pump-and-treat can be ineffective, and (c) accelerated rates of contaminant transport and extraction may be obtained. Electrokinetic extraction of metals and radionuclides from soils has been investigated by bench-scale tests, pilot-scale tests, and limited field applications (1-11). Recent developments of the process are summarized in a special issue of the Journal of Hazardous Materials on "Electrochemical Decontamination of Soil and Water" (12). Principles and applications of the electrokinetic remediation are also presented in Chapter 4 .