Electrochemical Transport, Transfer, and Transformation Processes

The implications of these electrolysis reactions are enormous in that they impact transport, transformation, and degradation processes that control the contaminant migration, removal, and degradation during electrochemical treatment. The different transport, transfer, and transformation processes induced by the applied electric field and how these processes are impacted by the electrolysis reactions at the electrodes are fundamental to the understanding of the electrochemical remediation technologies and are briefly presented in this section. 

For low-permeability media, advective transport due to hydraulic flow is negligible. The application of an electric fleld induces the transport of contaminants and water through the contaminated media toward the electrodes due to the following transport processes (Probstein, 2003) electromigration ionic migration), electroosmosis, electrophoresis, and diffusion. 

The extent of electromigration of a given ion depends on the conductivity of the soil, soil porosity, pH gradient, applied electric potential, initial concentration of the specific ion, and the presence of competitive ions. The electromigrative velocity 

2 Electroosmosis Advective flow occurs due to hydraulic gradient and electrical gradient. The hydraulic flow ( h) due to hydrauhc gradient (4) is defined 

In 1879, Helmholtz introduced one of the first theories concerning electroosmo-sis,andSmoluchowskimodifieditinl914.AccordingtotheHelmholtz-Smoluchowski theory (H-S theory), the electro-osmotic flow velocity (Veo) is directly proportional 

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