MOF-derived N-doped porous carbons activate peroxomonosulfate to efficiently degrade organic pollutants via non-radical pathways

Abstract

Carbon-based heterogeneous catalysts have attracted extensive attention due to their environmentally friendly nature and the absence of metal leaching concerns. Nonetheless, enhancements in catalyst preparation and their efficacy in activating Peroxymonosulfate (PMS) to degrade organic pollutants remain areas of research. This work synthesized a novel nitrogen-doped porous carbon material (NPCs) at different temperatures using MET-6 [Zn(C2N3H2)2] Metal-organic frameworks (MOFs) precursor through a one-step pyrolysis process. The optimized NPC-900 demonstrated an elevated specific surface area and richer pore structure, validated through diverse characterization techniques. The NPC-900 was employed to activate (PMS) to degrade organic pollutants. Key catalytic active sites contributing to rhodamine B (RhB) degradation by NPC-900 were identified as graphite N and sp2 hybrid carbons, achieving 99.75 % RhB degradation. Through radical scavenging tests and electron paramagnetic resonance (EPR) spectroscopy, both free radicals (SO4−, ·OH and O2−) and non-free radicals (1O2 and electron transfer) were detected during the RhB degradation process. As the reaction progressed, non-free radicals increasingly asserted their dominant role. Employing electrospray ionization-mass spectrometry (EIS-MS) further elucidated RhB degradation intermediates, facilitating the postulation of a probable mechanism for NPC-900 activation of PMS and the subsequent RhB degradation pathway. In summary, this study introduced a metal-free catalyst capable of activating PMS through an accessible synthetic approach, offering valuable insights for the proficient degradation of organic pollutants in wastewater.