Per-and polyfluoroalkyl degradation in a hybrid dielectric barrier discharge plasma and electrooxidation system through involving more reactive species by air and water circulation.

The presence of PFAS in water matrices has become a global environmental issue in the last half-century. Dielectric barrier discharge (DBD) and electrooxidation (EO) showed potential for PFAS degradation but have yet to find practical application due to relatively high energy consumption. In this study, a hybrid DBD-EO system for efficient degradation of PFAS was developed by involving more reactive oxygen, sulfate radicals (SO) and nitrogen species (RONS). The results showed that using the hybrid DBD-EO system under optimal conditions (applied voltage = 6 kV and current density = 7.5 mA/cm) could increase PFOA degradation efficiency from 65.0 % (DBD) and 62.5 % (EO) to 89.14 %. While the EE/O decreased from 67.0 kWh/m (DBD) and 47.82 kWh/m (EO) to 21.61 kWh/m. In addition, the effect of operational parameters and water matrices revealed that the hybrid DBD-EO system had high potential for PFOA removal from water under various conditions. According to the EPR and DFT calculation results, integration of reactive species in EO (SO, OH, O) and ONOOH) and DBD (OH, O, NO, O and ONOOH) processes in the DBD-EO system led to efficient degradation of PFOA through a mechanism of decarboxylation/defluorination cycle. Our findings suggested the combination of DBD and EO is a promising approach for complete degradation of PFAS from water with low energy consumption and minimal environmental side effects.