Chemiluminescence-assisted study on a peracetic acid-based advanced oxidation process activated with cobalt phosphide

In recent years, the elimination of organic pollutants using advanced oxidation processes (AOPs) based on peracetic acid (PAA) has drawn increasing attention due to the high oxidative potential and low byproducts. However, to explore more efficient and stable PAA-based AOPs, there is still great room for study on the activation of PAA and degradation mechanism in the reaction process. In this study, a new PAA-based AOP activated by metal-organic framework-derived cobalt phosphide (CoP) and accompanied by chemiluminescence (CL) behaviour was explored. The CoP/PAA system could efficiently degrade 99.98% of RhB (20 mg L^-1 ) within 5 min at pH 7 compared with the conventional Co₃ O₄ /PAA system (merely 17.29%), and the degradation process was matched well with the pseudo-first-order kinetic, and the kinetic constants was ~23.7 times higher than that of Co₃ O₄ (0.546 min^-1 for CoP vs. 0.023 min^-1 for Co₃ O₄ ). In the CoP/PAA/RhB process, the CL intensity was related to the concentration of ¹ O₂ , O₂ ^•- and acetyl peroxyl radicals [CH₃ C(O)OO• and CH₃ C(O)O•]. Therefore, CL analysis, combined with quenching tests and electron paramagnetic resonance analysis, was used to study the degradation mechanism in detail, and ¹ O₂ was confirmed as the dominant contributor for the dye degradation.