Modeling and Simulation of Copper Removal from the Contaminated Soil by a Combination of Adsorption and Electro-kinetic Remediation

Abstract

Electro-kinetic remediation technology is one of the developing technologies that offer great promise for the cleanup of soils contaminated with heavy metals. A numerical model was formulated to simulate copper (Cu) transport under an electric field using one-dimensional diffusion-advection equations describing the contaminant transport driven by chemical and electrical gradients in soil during the electro-kinetic remediation as a function of time and space. This model included complex physicochemical factors affecting the transport phenomena, such as soil pH value, aqueous phase reaction, adsorption, and precipitation. One-dimensional finite-difference computer program successfully predicted meaningful values for soil pH profiles and Cu concentration profiles. The model considers that: (1) electrical potential in the soil is constant with the time; (2) the effect of temperature is negligible; and (3) dissolution of soil constituents is negligible. The predicted pH profiles and transport of copper in sandy loam soil during electro-kinetic remediation were found to reasonably agree with the bench-scale electro-kinetic experimental results. The predicted contaminant speciation and distribution (aqueous, adsorbed, and precipitated) allow for an understanding of the transport processes and chemical reactions that control electro-kinetic remediation