Enhanced non-radical degradation of organic pollutants by peroxymonosulfate activation with Zr-Mn composite oxide

Non-radical activation of peroxymonosulfate (PMS) with MnOX can degrade organic pollutants more selectively. However, improving the performance of MnOX is still a challenge. In this work, a series of Zr-Mn composite oxides were synthesized by a hydrothermal method and characterized by various techniques. Their performance for PMS activation was studied using phenol and ofloxacin as the target pollutants. The characterization results show that the introduction of Zr into MnOX increased the oxygen mobility, while the surface area and surface oxygen content of the composite oxides decreased with increasing the content of Mn. The combination of Zr-Mn led to a synergistic effect for PMS activation and the sample (ZM2) with the Zr:Mn ratio of 1:1 exhibited the highest activity. This can be attributed to its high oxygen mobility, suggesting that the manipulation of oxygen mobility should be an effective strategy for improving the performance of PMS catalyst. Singlet oxygen was found to be the reactive species for pollutants degradation, and this process was barely affected by coexisting substances due to the non-radical mechanism. Moreover, ZM2 exhibited good stability and reusability, suggesting its potential application in wastewater treatment.