污染土壤中的重金属镉在电场力作用下的迁移模拟OA

Electrodynamic remediation of heavy metal-contaminated soil is a remediation method that forces heavy metal ions to migrate and accumulate near the cathode under the action of artificial electric fields,thereby removing soil heavy metal ions.Under laboratory conditions,electrokinetic remediation experiments are generally short,and the Cd2+content in soil often makes it difficult to meet the national low-risk standard(≤0.4 mg/kg).To study the effects and influencing factors of electric dynamic remediation of heavy metal-contaminated soil,a three-dimensional numerical model of electric dynamic remediation of heavy metal cadmium-contaminated soil was established using COMSOL Multiphysics field simulation software based on the solute transport equation.Numerical simulation experiments on the electric dynamic remediation of heavy-metal-contaminated soil were carried out to investigate the migration characteristics of Cd2+ions under the action of an electric field.The numerical simulation of cadmium ion migration distribution results is consistent with the experimental results under similar conditions,with an average relative deviation of 3.66%between the simulated and measured values,preliminarily verifying the applicability of the model for electric remediation of heavy-metal-contaminated soil.On this basis,the electric field strength was set to 2 V/cm,and the Cd2+ion concentration in the cathode chamber was not controlled during the remediation process.After 60 days of remediation,the Cd2+ion content in the soil was partially higher than 0.4 mg/kg.During the remediation process,the concentration of Cd2+ions in the cathode chamber was controlled.After 45 days of remediation,the Cd2+ion content in the contaminated soil remained below 0.4 mg/kg.Research has shown that the continuous accumulation of high concentrations of Cd2+ions in the cathode chamber during the remediation process can hinder the continued migration of heavy metal cadmium ions from the soil to the cathode chamber.Controlling the concentration of Cd2+ions in the cathode chamber can effectively reduce the reverse diffusion of cadmium ions and the hindering effect of the additional electric field they generate,thereby reducing remediation time and improving remediation efficiency.