N-Doped Low-Rank Coal Based Carbon Catalysts for Heterogeneous Activation of Peroxymonosulfate for Ofloxacin Oxidation Via Electron Transfer and Non-Radical Pathway

Advanced oxidation processes based on sulfate radicals were promising technologies for deep wastewater treatment. There was an urgent need of low-cost and green catalytic material. In this study, N-doped low-rank coal based carbon catalysts (NLCs) were prepared under different ratios and pyrolysis temperatures, which showed excellent catalytic performance for peroxymonosulfate (PMS) activation. The NLCs had a high degree of graphitization and good electrical conductivity, allowing for high ofloxacin removal rates. The N-doped structure lead to the formation of electron-rich regions, which favored the adsorption of PMS. Mechanistic studies revealed that the main reactive oxygen species in the NLC/PMS system was singlet oxygen ( 1 O 2 ), and that electron transfer pathways and surface-bound reactive complexes also played an important role in this system. The NLC/PMS system had a wide pH adaptation in practice and good resistance to inorganic anions and humic acids in the aqueous environment because of the electron transfer mechanism. Therefore, the prepared nitrogen-doped coal based carbon catalytic materials had good prospects for application in advanced oxidation processes for wastewater treatment