Nanosized Co-Fe spinel quantum dots anchored on activated carbon for enhanced VOCs mineralization via PMS-based AOPs coupled with wet scrubber

In this study, we have developed a liquid-phase wet washing process based on PMS advanced oxidation for the effective removal of toluene. Our approach involved synthesizing a high surface area composite catalyst (CFQ/AC) through a one-step process, in which 0 D CoFe2O4 was deposited onto low-cost activated carbon, endowing it with abundant surface-active sites that facilitate continuous PMS activation. The Co(Ⅲ)/Fe(Ⅲ) generated by the reaction captures electrons from the PMS, thus achieving Co(Ⅱ)/Fe(Ⅱ) regeneration and realizing two complete redox cycles of Co(Ⅲ)/Co(Ⅱ) and Fe(Ⅲ)/Fe(Ⅱ). During the liquid-phase catalytic reaction process, the CFQ/AC/PMS system consistently achieved a stable removal efficiency of over 96% within 2 h, with a selectivity of more than 80% for CO2, indicating high mineralization capability. Furthermore, based on the detection and analysis of GC–MS, there were few gaseous intermediates in the tail gas, leading to a significant reduction in secondary air pollution. By conducting electrochemical analysis and in-situ Raman spectroscopy, the transition metal valence changed and the combination of PMS with CFQ/AC formed charge transfer intermediates that led to toluene degradation. This mechanism utilized a cost-effective carbon-based composite catalyst, making it a practical and accessible solution for environmental applications.