High-temperature Electrothermal Remediation of Multi-Pollutant Soils

Abstract

Abstract Soil contamination is a global environmental issue due to rapidly increasing anthropogenic activities. Traditional processes for soil remediation often suffer from long treatment time, and lack generality because of different sources, occurrences, and chemical properties of the pollutants. Here, we report a high-temperature electrothermal process for rapid, water-free remediation of multiple pollutants in soil. The temperature of contaminated soil with conductive carbon additives ramps up to 1000 to 3000 °C within seconds via pulsed direct current input, enabling the vaporization of various heavy metals (Cd, Hg, Pb, Co, Ni, and Cu), and graphitization of persistent organic pollutants such as polycyclic aromatic hydrocarbons. The rapid treatment retains soil mineral constituents while increases water infiltration rate and exchangeable nutrient supply, leading to soil fertilization and improved germination rates. The process is energy-efficient with an electrical energy consumption of ~420 kWh ton-1, less than most conventional thermal remediation techniques. The potential for scaling up the process is outlined.