Efficient activation of peroxymonosulfate by MnS/Fe-MOF hybrid catalyst for sulfadiazine degradation: Synergistic effects and mechanism

In this work, MnS/Fe-MOF composites were synthesized by a mild one-pot method and employed as efficient activators of peroxymonosulfate (PMS) for sulfadiazine (SDZ) removal in water. The surface morphology and structure of MnS/Fe-MOF was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, flourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. As expected, the as-prepared MnS10/Fe-MOF presented complete SDZ degradation within 30 min in the presence of 0.2 g/L catalyst and 0.6 mM PMS, which was better than those with Co2S/Fe-MOF, CoS/Fe-MOF and MoS2/Fe-MOF as well as other reported catalysts. The effects of experimental conditions, co-existing anions and humic acid on catalytic performance of MnS/Fe-MOF were also investigated. Moreover, OH, SO4−, O2− and 1O2 were evidenced to participate in the activation process using quenching experiments and electro-spin resonance spectrometer. The results of XPS analysis of MnS10/Fe-MOF before and after the reaction confirmed the synergistic effects between multivalent Mn, Fe and S species in MnS/Fe-MOF, which was beneficial for the rapid Mn+1/Mn+ (M stands for Fe and Mn) recycling. This is the first work expounding the facile synthesis method of MnS/Fe-MOF composites and its synergistic mechanism as an efficient PMS activator for the degradation of antibiotics.