Numerical Study on the DBD Discharge Characteristics of Soil Particles in CO₂ Atmosphere

To better understand the discharge mechanism and pollutant degradation process of dielectric barrier discharge (DBD) in soil under a CO₂ atmosphere, a mathematical model and theoretical framework have been established. Based on a discharge kinetics model, this study simulates the discharge characteristics of a DBD soil system, and the simulation results show strong agreement with experimental data. The results reveal that regions of high electron density on the surfaces of soil particles induce more micro-discharges, thereby enhancing discharge efficiency. Significant changes in electron temperature on particle surfaces promote the generation of reactive species, which accelerate pollutant degradation. The electric field evolves from an initially uniform weak field to a localized strong field, which improves CO₂ ionization. A higher dielectric constant of soil particles improves electric field uniformity and expands the effective discharge area. At a peak voltage of 24 kV, electron density reaches an optimal level, while excessively high or low voltages lead to reduced performance. After CO₂ plasma enters the soil, long-lived reactive species such as O₃, O, CO₂(e₁), and CO₂(v₁) play key roles in pollutant degradation.