Enhancement of organic pollutant degradation in soil with dielectric barrier discharge plasma and MnFe2O4 catalyst: Performance and mechanism

The Dielectric Barrier Discharge plasma (DBD)-catalyst system holds promise for soil decontamination, but catalyst recycling is still challenging. In this study, a MnFe₂O₄ catalyst with recyclability and redox properties was prepared and applied in a DBD system to remove phenanthrene (Phe) from soil. The redox reaction in the MnFe₂O₄ improved the synthesis of reactive oxygen species (ROS), boosting Phe degradation from 80.21 % to 90.21 % within 5 min, with the corresponding kinetic constants was 1.4 and 2.1 times higher than DBD alone. After four recycling cycles, the Phe removal efficiency remained at 88.7 %. Based on the experiment results, the synergistic effect between DBD and MnFe₂O₄ induced oxygen vacancy formation and accelerated redox reactions, favoring the decomposition of O₃ and the degradation of Phe. Furthermore, the Phe degradation pathways were elucidated through the analysis of intermediates in the DBD-MnFe₂O₄ system. This work provides new insight for developing soil remediation systems with environmentally friendly and high efficiency.