Revealing the importance of non-radical mechanisms in the degradation of sulfamethazine by Lewis acid-etched Co@MXene-activated peroxyacetic acid

The activation of peracetic acid (PAA) based advanced oxidation processes (AOPs) has emerged as a research hotspot in eliminating organic pollutants. Here, Co@MXene etched with a Lewis acid was employed to activate PAA for the treatment of sulfamethazine (SMT) polluted water. The technology had efficient degradation performance for SMT, achieving 82.1% degradation within 8 minutes. Reactive species competition experiments, chemical probe experiments and electron spin resonance (ESR) analyses were used to confirm the important role of the non-radical pathway. Density functional theory calculations were conducted, revealing that the activation of PAA led to the generation of acetyl peroxyl radicals with an activation energy barrier, and particularly highlighting the significant contribution of high-valent metals to the degradation of SMT. Electrochemical tests showed that PAA formed a substable complex with Co@MXene to directly degrade SMT. The overall pathway was proposed and the activation status of PAA in surface water was assessed. Ultimately, the aggregate results from this study highlight the impressive activation mechanisms of PAA to further deepen the understanding of PAA-based AOPs. Co@MXene activation of peracetic acid and degradation of sulfamethazine via two major pathways: non-radical activation and organic radical activation.