Mechanistic study of air dielectric barrier discharge plasma on soil- bound microplastics: From reactive species dynamics to polymer degradation

CT Lan and HW Zhu and DW Liu, JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING, 13, 118773 (2025).

DOI: 10.1016/j.jece.2025.118773

This study investigates the multiscale mechanisms of polyethylene (PE) microplastic degradation in soil using air dielectric barrier discharge (DBD) plasma. By coupling a two-dimensional fluid discharge model with molecular dynamics simulations, we reveal how plasma streamers generate localized electric fields (similar to 10(7) V/m) and high electron densities (similar to 10 (13)-10 (14) cm(-3)), facilitating the formation of reactive oxygen species (ROS) such as O, O-3, center dot OH, and H2O2. Among these, center dot OH and O-3 exhibit superior degradation efficacy. Temperature plays a pivotal role: at 650 K, reaction barriers are significantly reduced, allowing ROS to cleave PE chains via hydrogen abstraction and cycloaddition. H2O2 contributes effectively as a secondary center dot OH source under thermal activation. Surface protrusions on MPs intensify local fields, while recessed areas limit plasma access. These findings are consistent with experimental trends and provide mechanistic insights into the spatial and thermal dynamics of plasma-soil-microplastic interactions. The results offer valuable design principles for optimizing plasma-assisted soil remediation, emphasizing the integration of chemical reactivity, thermal responsiveness, and microplastic morphology.

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