methanol synthesis

water oxidation

oxidation

degradation

catalytic performance

pms activation

peroxymonosulfate pms

advanced oxidation

degradation methylene

Journal of Hazardous Materials

Research interests have been recently thrust into the nonradical reactions in persulfate-based advanced oxidation processes (AOPs), whilst the underlying mechanism of the nonradical pathway remains ambiguous especially in metal-based AOPs systems. In this study, we investigated the reactivity of cuprous oxide (Cu2O) for activating peroxymonosulfate (PMS) to decompose diverse organic contaminants. Cu2O exhibited a strong catalytic dependence on the crystal morphology, and cubic Cu2O was more reactive than the octahedral and rhombic dodecahedral structures for catalytic degradation of bisphenol A with PMS. Chemical quenching tests, electron paramagnetic resonance (EPR), solvent exchange and selective oxidation experiment were corporately conducted to illustrate that Cu2O-catalyzed PMS did not produce free radicals or singlet oxygen. In contrast, a surface-confined metastable intermediate would be formed via outer-sphere interactions between PMS and Cu2O, which directly attacked the organic substrate. Such a reaction pathway is intrinsically distinct from the electron-shuttling regime in carbon (or noble metal)/persulfate systems via the conductive surface of the catalyst, and the outer-sphere interactions let the activated PMS demonstrate a higher oxidizing capacity toward organic contaminants. Therefore, this study dedicates to providing new insights into the copper-catalyzed AOPs and vital supplementary to the ongoing dialogue of the nonradical catalysis in persulfate-based oxidation.

Structure-dependent catalysis of cuprous oxides in peroxymonosulfate activation via nonradical pathway with a high oxidation capacity