Catalytic Activation of Peroxymonosulfate by Mn/N Co-Doped Porous Carbon for Effective Phenol Degradation: Crucial Role of Non-Radical Pathways

Abstract

In the degradation process of organic pollutants, compared with the free radical pathway, the non-radical pathway shows the advantages of mild oxidation ability, strong anti-interference, and adaptation to different pH values. In this study, a manganese-nitrogen co-doped porous carbon (Mn-N@C-1) with high nitrogen content was prepared to improve the contribution rate of non-radical pathways to the degradation process of organic pollutants. The high performance of Mn-N@C-1 is attributed to the formation of Mn-Nx sites between Pyridine N and Mn, which can effectively oxidize organic pollutants in water (phenol, bisphenol A, 2, 4-dichlorophenol). In addition, the catalyst exhibits high catalytic activity over a wide pH range (pH=3-9) and has good immunity to inorganic anions. Moreover, the Mn-Nx site and graphitic-N are considered to be the generation sites of singlet oxygen, and the role of metastable Mn-N@C-1/PMS* complexes in the electron transfer process is explored. Overall, this study explores the crucial role of non-radical pathways in the degradation of organic pollutants by carbon-based materials.

Keywords: Peroxymonosulfate, Mn/N co-doping, Electron transfer, Singlet oxygen, Nonradical pathway