Optimized Cu2O-{100} facet for generation of different reactive oxidative species via peroxymonosulfate activation at specific pH values to efficient acetaminophen removal

Activation of peroxymonosulfate (PMS) to degrade persistent organic contaminants has received increasing attention in wastewater purification. In this study, Cu2O catalysts with different exposed crystal facets were prepared, characterized, and evaluated for acetaminophen (ACE) degradation through PMS activation. The experimental results showed that cubic Cu2O with {100} facets exhibited remarkable activity on ACE removal by PMS activation in wide pH range of 3–11. DFT calculations indicated that Cu2O-{100} displayed higher electron transfer efficiency and PMS adsorption ability, further improving PMS activation. The radicals quenching experiments and electron paramagnetic resonance (EPR) results illustrated that singlet oxygen (1O2) was dominant reactive oxidative species (ROSs) during oxidation reactions and the relevant generation pathways were distinctly elucidated. Finally, the possible PMS activation mechanisms were discussed for ACE degradation in a wide pH range. This study will provide new insights to disclose PMS-based advanced oxidation processes (AOPs), and offer a new approach for wastewater purification by non-radical reactions.