Eu2O3/Co3O4 nanosheets for levofloxacin removal via peroxymonosulfate activation: Performance, mechanism and degradation pathway

In this study, Eu2O3/Co3O4 nanosheets (NSs) were successfully synthesized and employed to degrade levofloxacin (LVX) via peroxymonosulfate (PMS) activation. Owing to the enhanced transfer efficiency of Co2+/Co3+ and more adsorbed oxygen, the obtained Eu2O3/Co3O4 NSs displayed better catalytic performance for PMS activation toward LVX degradation than pure Co3O4. The Eu2O3/Co3O4 NSs can remove 97.93% of LVX only in 6 min via activating PMS, with a reaction rate constant (0.2346 min−1) , which was 2.3 folds of single Co3O4 NSs (0.1003 min−1). Besides, Eu2O3/Co3O4 exhibited good catalytic performance in presence of different inorganic anions, satisfactory stability and reusability. Singlet oxygen (1O2), hydroxyl radical (•OH), sulfate radical (SO4•−) and superoxide radical (•O2−) contributed to LVX degradation and 1O2 played the most key role. In addition, based on the ROSs and LVX degradation intermediates, the possible mechanism and degradation pathways of LVX were further cleared in detail. This work can provide a reference for the eco-friendly and facile preparation strategy of efficient and stable catalysts for rapid and efficient removal of recalcitrant pollutants.