Facile synthesis of Cu-doped manganese oxide octahedral molecular sieve for efficient degradation of sulfamethoxazole via peroxymonosulfate activation

Recently, peroxymonosulfate-based advanced oxidation processes have turned out to be the one of most efficient approaches for the elimination of toxic and refractory organic pollutants from sewage. Because the electron withdrawing group SO4− was easily activated to release reactive species, including sulfate radical (·SO4−), hydroxyl radical (·OH), superoxide radicals (·O2-) and singlet oxygen (1O2), all of which could induce the degradation of organic contaminant. In this work, we had synthesized a variety of M-OMS-2 nanorods (M=Co, Ni, Cu or Fe), by doping of Co2+, Ni2+, Cu2+ or Fe3+ into manganese oxide octahedral molecular sieve (OMS-2), as high-efficiency nano-catalysts for efficient removal of sulfamethoxazole via peroxymonosulfate (PMS) activation. The comparison of catalytic performance of M-OMS-2 in sulfamethoxazole elimination via PMS activization exhibited that the order of sulfamethoxazole removal rate as follow: Cu-OMS-2 (96.4%) > Co-OMS-2 (88.0%) > Ni-OMS-2 (87.2 %) > Fe-OMS-2 (35.0%) > OMS-2 (33.5%). Then, the kinetics and structure-activity relationship of M-OMS-2 nanorods in the elimination of sulfamethoxazole were investigated. The feasible mechanism of sulfamethoxazole degradation via Cu-OMS-2/PMS system was further investigated by quenching experiment, HR-MS and EPR. In addition, we found that sulfamethoxazole degradation efficiency was obviously boosted in both sea water and tap water, demonstrating the great potential application of Cu-OMS-2/PMS system in the real sewage treatment.