Activation of peracetic acid with cobalt anchored on 2D sandwich-like MXenes (Co@MXenes) for organic contaminant degradation: High efficiency and contribution of acetylperoxyl radicals

[Display omitted] •Anchoring cobalt on sandwich-like 2D MXene shows synergistic effect on PAA activation.•Highly efficient degradation of 2,4-DCP is observed at neutral condition.•Ti3C2Tx MXene substrate accelerates recycling of ≡ Co(III)/≡ Co(II).•Acetylperoxyl radical is primarily responsible for contaminant degradation.•The Co@MXenes/PAA process was unaffected by water matrices. A novel Co@MXenes catalyst with unique structure was prepared through randomly anchoring cobalt on 2D sandwich-like MXenes to activate peracetic acid (PAA) for water decontamination. Compared to the conventional Co3O4 nanomaterial, the Co@MXenes catalyst exhibits superior performance for PAA activation under neutral condition. In-depth investigation revealed that the Ti3C2Tx MXene substrate triggered the ≡ Co(III)/≡ Co(II) cycle, which greatly enhanced the activation of PAA. The XPS and ICP techniques further demonstrated that Co@MXenes was highly stable with extremely low cobalt ion leaching and hence a superior reusability was obtained. Moreover, acetylperoxyl radical (CH3CO3) was identified as the primary radical species responsible for organic micropollutants degradation, exhibiting high selectivity towards contaminants containing electron-rich groups. The novel technology exhibited a high tolerance of Cl− and good performance in real wastewater treatment. This work provides a promising effective catalyst for PAA activation and will facilitate PAA application in wastewater decontamination.