Oxygen-enriched vacancy Co2MnO4 spinel catalyst activated peroxymonosulfate for degradation of phenol: Non-radical dominated reaction pathway

Spinel is a desirable catalyst for active peroxymonosulfate (PMS) to degrade organic pollutants in complex water matrix. In this study, spinel-type Co2MnO4 catalyst were successfully synthesized and employed as an efficient PMS activator for the degradation of phenol in water (up to 100 % within 45 min, degradation rate constant (k) is 0.076 min−1) at initial PH of 6.3. The excellent catalytic activity of Co2MnO4/PMS system was found to be attributed to its unique porous structure, oxygen vacancies and the synergistic effect of Co and Mn. Sulfate radicals (SO4−) and singlet oxygen (1O2) all contributed to phenol degradation, and 1O2, a non-radical pathway mainly provided by oxygen vacancies of Co2MnO4, is the dominant reactive species in the activation system. The Co2MnO4/PMS system had good resistance to the common inorganic anions (Cl−, HPO42−, HCO3− and NO3−) and exhibited great reusability due to the strong Co/Mn interaction. Finally, the phenol degradation mechanism in Co2MnO4/PMS system was also proposed based on the detected intermediates by GC–MS. Overall, the system composed of oxygen-enriched vacancy Co2MnO4 spinel catalyst and PMS has good degradation efficiency and is suitable for the remediation of organic pollutants in wastewater.