Highly Efficient and Selective Degradation of Electron-Rich Organic Pollutants in a Co-CN/Peroxymonosulfate System via the Synergistic Interaction of Regulating the Active Site and Producing Singlet Oxygen

Abstract

Singlet oxygen ( 1 O 2 ) generation during peroxymonosulfate (PMS) activation is crucial for the selective removal of emerging electron-rich organic contaminants (EROCs) in complex water matrices. However, the efficient and selective production of 1 O 2 during PMS activation remains a significant challenge. Herein, an N-doped carbon material with a uniform dispersion of Co nanoparticles was synthesized for the effective generation of 1 O 2 and the selective removal of refractory EROCs. The precursor was deliberately designed by anchoring Co 2+ with L-histidine to achieve strong binding of Co−N X sites and introducing sufficient N sources by doping with melamine to improve the electronic structure of adjacent carbon atoms and a uniform distribution of Co nanoparticles with reduced particle size. This material achieved efficient and selective removal of EROCs over a wide range of pH values. Multiple characterizations demonstrated that the active species during the reaction were 1 O 2 , and electron transfer facilitated the degradation reactions, which contributed to the high reactivity and selectivity. Density functional theory calculations further confirmed that the presence of a Co−N X site is favorable for PMS activation to selectively produce 1 O 2 . This study provides a new approach for developing materials to effectively generate 1 O 2 and selectively degrade EROCs.