Co3O4 coated carbon fiber activates PMS to degrade phenolic pollutants via 1O2 dominated non-radical pathway: Role of dual reaction center

Carbon fiber (CF) with a regular fiber skeleton structure was used to prepare the Co3O4@CF catalyst. The as-prepared catalyst was then applied to activate peroxymonosulfate (PMS) for the degradation of phenolic pollutants. Furthermore, the catalytic performance and degradation mechanisms are investigated in this study. The uniform dispersion of Co3O4 on the surface of the CF, as well as the presence of Co–O–R in the Co3O4@CF structure, was confirmed. Notably, 50 mg L−1 of bisphenol A (BPA) was completely degraded in the Co3O4@CF/PMS system within 20 min, under initial conditions of catalyst mass concentration at 0.2 g L−1, the PMS concentration at 10 mmol L−1, and a pH of 6.6. The total organic carbon removal rate reached 72.33 % over 90 min, indicating that the Co3O4@CF/PMS system exhibited strong mineralization capability for BPA. Furthermore, the catalyst demonstrated high efficiency in treating various types of refractory organic pollutants, showing promise for purifying coking wastewater from 3D-EEM. X-ray photoelectron spectroscopy and solid-state electron paramagnetic resonance revealed the formation of electron-poor and electron-rich centers in the Co3O4@CF structure. Density functional theory calculations further indicated that the charge density around the CF decreased, while the charge density around Co3O4 increased, resulting in the formation of these electron-poor and electron-rich centers. Electrochemical characterization using cyclic voltammetry and electrochemical impedance spectroscopy confirmed the excellent electron transfer rate of Co3O4@CF. Additionally, the reactive oxygen species dominated in the Co3O4@CF/PMS system were 1O2 and •O2−, with possible mechanisms for the 1O2 and •O2− generation during BPA degradation elucidated. Moreover, liquid chromatography-mass spectrometry results identified degradation intermediates of BPA, proposing three possible degradation pathways. [Display omitted] •Carbon fiber with regular fiber skeleton was used to prepare Co3O4@CF catalyst.•It demonstrated the excellent electron transfer rate of Co3O4@CF.•1O2 was the main reactive oxygen species in the Co3O4@CF/PMS system.•It displayed high catalytic efficiency for various types of refractory organic pollutants.•It also shown capable promising in purifying actual coking wastewater.