Superior bensulfuron-methyl degradation performance of sphercial magnetic Co3O4@C-500/peroxymonosulfate system by enhancing singlet oxygen generation: The effect of oxygen vacancies

Singlet oxygen (1O2) could enhance the organic pollutant degradation ability due to its high selective oxidation of electrophilic compounds. Magnetic Co3O4 spheres embedded in carbon oxides (Co3O4@C-500) with oxygen vacancies were designed and synthesized by hydrothermal method and heat treating, which enhanced electronic transfer and contributed to the generation of 1O2, improving the organic pollutants degradation performance. 1O2 was produced by the reaction between oxygen vacancies and dissolved oxygen mainly, accompanying by oxygen vacancies activating PMS alone for small portion. Co3O4@C-500/PMS system could be applied in a wide pH range for the efficient removal of bensulfuron methyl (BSM). Co3O4@C-500 was magnetic and could be collected by a magnet and rapidly separated from degradation solution, displaying strong stability and good reusability. Possible degradation mechanism of BSM were explored in detail. The BSM degradation intermediates were identified by High Performance Liquid Chromatography-Time of Flight-Mass Spectrometry (HPLC-TOF-MS2) and the degradation pathways were proposed. This study shed light on the 1O2 generation mechanism of catalyst containing oxygen vacancies and gave a guide to the design and preparation of highly efficient multifunctional catalysts.