2005 Volume 52 Issue 3 Pages 136-144
Electrokinetic soil remediation by electroosmosis and ionic migration is restricted to soluble substances. At a higher pH, the soil particles sorb more heavy metals than at a lower pH and the precipitation reactions of heavy metals are promoted. Both mechanisms make heavy metals immobile, rendering cleanup more difficult and electrokinetic extraction inefficient. Therefore, the acidification of soils is very important to increase the cleanup efficiencies of heavy metals by electrokinetic method from contaminated soils. In the present study, acidification of soils are predicted with a numerical method in which electrical flow is coupled with hydraulic flow, and the effects of some factors such as electrode configuration, electric field strength and electrode spacing for the saturated soils are investigated. The results obtained this study are summarized as follows:
The two-dimensional electrode configurations containing cathode surrounded by three or more anodes rapidly acidify the soils compared with one-dimensional electrode configuration. However, two-dimensional electrode configurations develop spots of inactive electric field between cathodes. A larger electrode spacing increases the processing time required. Meanwhile, a larger electric field strength reduces the processing time required.