Electrokinetic Remediation. II: Theoretical Model

Abstract

A mathematical model is presented for multicomponent species transport under coupled hydraulic, electric, and chemical potential differences. Mass balance of species and pore fluid together with charge balance across the medium result in a set of differential equations. Sorption, aqueous phase, and precipitation reactions are accounted by a set of algebraic equations. Instantaneous chemical equilibrium conditions are assumed. Transport of H + , OH − , Pb 2+ , NO-, the associated chemical reactions, electric potential, and pore pressure distribution across the electrodes in electrokinetic remediation are modeled. Model predictions of acid transport, lead transport, and pore pressure distribution display very good agreement with the pilot-scale test results validating the formalisms offered for multicomponent transport of reactive species under an electric field. The model also bridges the gap between the electrochemistry and mechanics in electroosmotic consolidation of soils.