Construction of CuBi2O4/MnO2 composite as Z-scheme photoactivator of peroxymonosulfate for degradation of antibiotics

In this study, CuBi2O4/MnO2 composite was successfully prepared by a two-step hydrothermal method and served as a low-cost and non-toxic catalyst for photo-Fenton reaction. Meanwhile, several refractory pollutants including ceftiofur (CEF), tetracycline (TC) and lomefloxacin (LOM) could be efficiently eliminated within 40 min. Particularly, the influence of experimental parameters towards CEF degradation were systematically studied in detailed. 93.6% of CEF was decomposed over 40 min with 0.4 g.L-1 PMS and 0.3 g.L-1 CuBi2O4/MnO2 at pH 11. After this, active species scavenging experiments were conducted and the results exhibited that sulfate radicals, hydroxyl radicals, holes and superoxide radicals participated in the degradation of CEF. Besides, CuBi2O4/MnO2 composite possessed high stability and reusability based on continuous cycle experiments. Moreover, based on the analysis of HPLC/MS, three possible degradation pathways of CEF were put forward and the degradation mechanism of CEF was elucidated.