Investigation of Streaming Potential Flow of Heavy Metal Ion Contaminants in Soil Matrix: An Area-Averaging Approach.

Abstract

"Several electro-kinetic phenomena such as electro-viscous effects, streaming potential, electro-kinetic dispersion, etc. are some of the phenomena that occur during the flow of fluids and electrolytes in capillary channels having surface charges. When the dimensions of this capillary are on the same order of magnitude as the electrical double layer, EDL formed during such flows, the effects and phenomena cannot be ignored and they add up to define the characteristics and properties of the system.
For soil electrokinetic cleaning, the system under consideration is a contaminated soil matrix made up of capillaries of rectangular (or other geometries) with walls having (frequently) constant and uniform surface charge. The pressure-driven flow of heavy metal contaminants in the presence of an in-situ streaming potential is the subject of investigation in the study. The mathematical framework for this study is based on the area-averaging approach. By taking advantage of the disparate axial and transverse length scales of the microchannel pores found in the soil matrix, this approach helps to facilitate the development of a mathematical model that is based on effective parameters by which parametric studies can be conducted. The results would provide insight into the effect of combined pressure-driven and electroosmotic flows for electro-kinetic soil remediation. The effect on the effective velocity of macro-heterogeneities, related to the orientation of individual pores in the soil matrix is also investigated and illustrated"