Efficient peroxymonosulfate activation by CoOOH immobilized on porous graphitized carbon toward volatile organic compounds degradation: Radical and non-radical pathways

Wet scrubbing coupled with an advanced oxidation process (AOPs) holds significant potential for the removal of volatile organic compounds (VOCs). In this study, novel CoOOH nanosheets anchored on the surface of porous graphitized carbon (PGC) were synthesized as an efficient peroxymonosulfate (PMS) activator for the degradation of toluene. The experimental results demonstrated that supporting CoOOH nanosheets onto the PGC surface not only improved the aggregation state of CoOOH, increased the specific surface area of the catalyst, and synergized the components to enhance VOCs degradation, but also improved the catalyst's stability. Under optimal conditions, the toluene removal efficiency of the CoOOH/PGC catalyst remained as high as 89 % after 500 min. Quenching experiments and electron spin resonance (ESR) experiments confirmed the participation of multiple active species in the toluene degradation process, with singlet oxygen (¹O₂) and superoxide radicals (O₂^•-) identified as the principal active species in the CoOOH/PGC-PMS system. Furthermore, the degradation pathway of toluene was reasonably hypothesized based on density functional theory (DFT) calculations and gas chromatography-mass spectrometry (GC-MS) analysis. This work provides new insights into the enhanced effect of PGC within the CoOOH/PMS system and presents a high-performance solution for the wet scrubbing-coupled advanced oxidation organic waste gas treatment process.