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.