Non-radical pathway dominated mechanism of nitrogen-phosphorus co-doped porous carbon activated peroxymonosulfate: Synergistic regulation of N-P and ecological toxicity reduction

Environmentally friendly advanced oxidation (AOPs) is an effective means to treat trace amounts of antibiotics in water. However, traditional transition metal catalysts face challenges of metal leaching, limiting their practical utility. In this research, by activating peroxymonosulphate (PMS) using a nitrogen-phosphorus co-doped porous carbon (NP-HPMC-900) catalyst, a non-radical-dominated degradation mechanism was achieved. Material characterization revealed uniform distribution of N (3.35 at%) and P (2.56 at%) dopants in NP-HPMC-900, significantly enhancing the electronic structure and defect density ( I D /I G = 0.86) of the carbon framework. Catalytic degradation experiments demonstrated that NP-HPMC-900 achieved 90 % tetracycline hydrochloride (TCH) removal within 30 min at pH 4, 6 and 10, with a superior apparent speed constant ( k obs = 0.02671 min −1 ) compared to conventional metal-based catalysts. Density functional theory (DFT) calculations confirmed that N-P doping modulated the local electron density of carbon matrix, enhancing its electron donor properties and PMS activation capability. Ecological toxicity assessments revealed significantly reduced phytotoxicity of degradation products, validating environmental safety. This study proposes a general strategy for activating PMS through N-P co-doped carbon materials from the perspective of catalyst-PMS synergistic degradation of pollutants, providing theoretical and practical insights into metal-free catalysts for sustainable water treatment.