Catalytic degradation of polyethylene terephthalate microplastics by Co-N/C@CeO2 composite in thermal-assisted activation PMS system: Process mechanism and toxicological analysis

In this work, a Co-N/C@CeO 2 composite material was successfully synthesized via hydrothermal, in-situ growth, calcination methods and applied in a thermal-assisted activation peroxymonosulfate (PMS) system for efficient degradation of polyethylene terephthalate microplastics (PET MPs). The effects of various parameters, including catalysts, reaction temperature, H 2 O 2 , PMS dosages and catalyst loading, on the degradation efficiency of PET MPs were systematically investigated. Characterization techniques, including mass spectral (MS) analysis, in-situ Fourier transform infrared (in-situ FT-IR) and electron paramagnetic resonance (ESR), revealed that PET MPs adsorbed on the surface were rapidly degraded under the action of hydroxyl radical (•OH) and sulfate radical (SO 4 •− ). In the presence of a small amount of H 2 O 2 and the synergistic effect, the Co-N/C@CeO 2 composite material successfully achieved a 92.3% degradation rate of PET MPs in the thermal-assisted activation PMS system. DFT calculations indicated that the Co-N/C@CeO 2 composite material exhibited relatively lower adsorption energy and higher activation capacity for HSO 5 − molecules. In addition, toxicity assessment results showed that the degradation intermediates had generally lower toxicity. This study not only provides valuable insights for the construction of high-activity Co-N/C and CeO 2 composite materials but offers technical and theoretical guidance for the effective degradation of PET MPs in the environment.