Unveiling reaction mechanisms of copper-based catalysts for peroxymonosulfate activation in Fenton-like reactions for sustainable water decontamination

Peroxymonosulfate (PMS) based Fenton-like reaction have attracted wide concerns for remediation of wastewater, but the temperature regulation for catalysts effectivity remains unclear.Here, the copper-based nanomaterials were synthesized by regulating the copper valence under different calcination temperature and it was also used as a Fenton-like catalyst to activate PMS for the degradation of oxytetracycline (OTC). The results showed that Cu 2 O/Cu-450 catalysts exhibited the best catalytic performance in activating PMS to degrade OTC, with a removal rate of over 95% within 16 min. Various characterization techniques revealed that the crystal structure and surface properties of the materials were significantly affected by the calcination temperature. Quenching experiments and electron paramagnetic resonance results indicated that the main reactive oxygen species in the system were singlet oxygen and superoxide radicals. The Cu 2 O/Cu-450-PMS system showed strong tolerance to changing pH range (4-10) and water environments and this reaction system also possessed high degradation efficiency towards to oxytetracycline, tetracycline, methyl orange, phenol, and ciprofloxacin. The OTC degradation followed pseudo-first-order kinetics, Cu 2 O/Cu-450 with a rate constant of 0.193 min -1 , which was 3.06 and 2.57 times higher than those of CuO-250 and Cu-650. The analysis of toxicity estimation software tool showed that the toxicity of OTC and its degradation intermediates was significantly reduced. This study provides a high-effective and feasible method for effectively removing OTC from polluted water.