Selective sulfite activation based on a non-radical reaction pathway with dominant 1O2 generation triggered by oxygen vacancies-enriched CuCo2O4 for efficient degradation of Ciprofloxacin

In general, sulfite activation systems follow a radical generation pathway and non-radical pathways are rare. Different from previous sulfite activation through reactive oxygen species (ROS) pathways, CuCo 2 O 4 -O v rich in oxygen vacancies prepared by simple NaBH 4 treatment can removal ciprofloxacin (CIP) by singlet oxygen ( 1 O 2 ) non-radical pathway and its dominant role proved by the quenching experiments, showing outstanding catalytic performance over a wide pH range. In addition, 1 O 2 has been identified to originate from: SO 5 •- , SO 4 •- , and O 2 •- . The interaction of the presence of O v on the sulfite activation of CuCo 2 O 4 was investigated through a density functional theory (DFT) calculation, electrochemical analysis and XPS. The results indicate that O v can regulate the charge distribution, facilitating electron transfer between the catalyst and sulfite, and enhancing the adsorption and activation of sulfite. Notably, the selectivity of 1 O 2 generation is influenced by O v . The possible degradation pathways of CuCo 2 O 4 -O v were analyzed using liquid chromatography-mass spectrometry (LC-MS), and the toxicity of CIP and its intermediates was assessed using ECOSAR software. Finally, experiments confirmed that CuCo 2 O 4 -O v exhibits good universality and reusability. It is the synergistic activation of sulfite and degradation CIP by singlet oxygen non-free radical pathway by CuCo 2 O 4 catalyst and oxygen vacancy that will provide a new perspective for the activation of sulfite and has good reference value.