Understanding the Role of Electrokinetics-Hydrodynamics in Electrical-Field Based Soil Remediation

Abstract

The applied electrical field mediated process of cleaning a contaminated soil matrix in order to remove the contaminants (i.e. organic materials, inorganic and heavy metal ions, etc.) is affected by the electrokinetic forces. These forces help to move the contaminants from one position of the soil to another where they can be drained. The technique is very promising and it can be made more efficient through better understanding of the fundamental principles that govern this process. A useful way to achieve this aim is through mathematical modelling of the fluid flow and the solutes’ transport of these contaminants. In this work, we present an analysis of the role of electrokinetics-hydrodynamics in facilitating soil cleaning. In particular, we assume a soil matrix with rectangular capillaries and a Newtonian buffer to compute the electroosmotic flow. The electrokinetic force is computed by using the Poisson-Boltzmann equation coupled with the Debye-Huckel approximation assuming a uniform charge on the capillary walls. The macro-heterogeneity of the capillary in the soil matrix (i.e. orientation of the capillary) is investigated along with other relevant parameters. The results are of importance in order to understand contaminant transport under the presence of capillary-wall reactions and in order to improve the  efficiency of the process.