Electroosmotic flow through porous media: cylindrical and annular models

Electroosmotic flow rates through porous media are predicted through the cylindrical and annular geometrical models. Differences in the results obtained from the two models are compared and discussed by making reference to the electrokinetic remediation of contaminated soil. In the annular-model case, when the electrical potential on the outer wall is less than on the inner wall and/or the double-layer thickness is much shorter than the outer radius, a maximum flux is predicted at some outer-to-inner-radii ratio. At a given soil porosity, the cylindrical model predicts a higher flow rate than the annular model, and the difference becomes increasingly more pronounced as the radii ratio approaches unity, which corresponds to a low-porosity soil.