Activation of peroxymonosulfate with MgO/Co3O4 catalyst for efficient decomposition of Lomefloxacin: activation mechanism, degradation pathway, and toxicity assessment

Abstract

To improve the degradation efficiency of PMS-advanced oxidation system, in this paper, a MgO/Co3O4 composite catalyst was prepared by Co3O4 modification on MgO surface through simple hydrothermal process and subsequent calcination. Then, advanced oxidation system of MgO/Co3O4 activated peroxymonosulfate (PMS) was established to degrade Lomefloxacin (LMF). The identification results of active substances showed that, •OH and SO4•−, •OH and 1O2 produced in MgO/Co3O4/PMS system contributed greatly to the degradation of LMF, and ∙O2−also played a certain role, but it was not as good as the first three active substances. Oxygen vacancies and hydroxyl groups on the surface of MgO/Co3O4 accelerate the electron transfer between Co2+ and Co3+, thus improving the cycle efficiency of Co3+/Co2+. Consequently, degradation rate of Lomefloxacin reached 97.88% in 30 min using MgO/Co3O4 +PMS system. Especially, MgO/Co3O4 shows good stability, and no significant change was observed in its catalytic performance during 6 consecutive cycles, which proved that MgO/Co3O4 showed good practical application value.