Reactive Nitrogen Species Generated by Gas-Liquid Dielectric Barrier Discharge for Efficient Degradation of Perfluorooctanoic Acid from Water

Perfluorooctanoic acid (PFOA) poses a serious threat to the ecological environment and biological health because of its ubiquitous distribution, extreme persistence, and high toxicity. In this study, we designed a novel gas-liquid dielectric barrier discharge (GLDBD) reactor which could efficiently destruct PFOA. PFOA removal efficiencies can be obtained in various water matrices, which were higher than 98.0% within 50 min, with energy yields higher than 114.5 mg.kWh(-1). It was confirmed that the reactive species including e(-), ONOOH, center dot NO2, and hydroxyl radicals (center dot OH) were responsible for PFOA removal. Especially, this study first revealed the crucial role of reactive nitrogen species (RNS) for PFOA degradation in the plasma system. Due to the generation of a large amount of RNS, the designed GLDBD reactor proved to be less sensitive to various water matrices, which meant a broader promising practical application. Moreover, influential factors including high concentration of various ions and humic acid (HA), were investigated. The possible PFOA degradation pathways were proposed based on liquid chromatograph-mass spectrometer (LC-MS) results and density functional theory (DFT) calculation, which further confirmed the feasibility of PFOA removal with RNS. This research, therefore, provides an effective and versatile alternative for PFOA removal from various water matrices.

Automated summary

The novel GLDBD reactor was designed to efficiently degrade PFOA with removal efficiencies over 98.0% within 50 minutes and energy yields exceeding 114.5 mg.kWh(-1). Reactive nitrogen species were identified as crucial for PFOA degradation in the plasma system, making the reactor less sensitive to various water matrices and promising for practical application. The research proposed possible PFOA degradation pathways based on LC-MS results and DFT calculation, providing an effective and versatile alternative for PFOA removal from different water matrices.