A Multiphysics Model for Evaluating Electrokinetic Remediation of Nuclear Waste-Contaminated Soils

With the widespread use of nuclear power, soil contamination by nuclear waste is causing increasing concerns around the world. Traditional technologies for soil remediation, such as geomelting, have limited uses due to high cost of energy. More sustainable solutions such as electrokinetic remediation using low direct current, within this context, are gaining more popularity for cleaning up contaminated soils. In this paper, a mathematical model was developed to evaluate the technique of electrokinetic remediation as a potential strategy for removing nuclear waste from variably saturated soils. Multiple species-driven mechanisms were coupled in one governing partial differential equation of high nonlinearity, which was then solved using the finite element method (FEM). The binding effect between transporting species and soil matrix was taken into account in the FEM model based on Langmuir adsorption isotherm. The numerical model was validated experimentally and then applied to evaluate the effectiveness and efficiency of electrokinetically removing a typical radioactive species from nuclear waste, uranium dioxide ions (UO22+). According to the predicted results, a soil sample at the dimensions of 10 cm in width and 10 cm in depth can be cleaned 12 h by applying a level of 8-V direct electric potential between two panel electrodes.