Synthesis of OMS-2/graphite nanocomposites with enhanced activity for pollutants degradation in the presence of peroxymonosulfate.

The octahedral molecular sieve manganese oxide (OMS-2) and graphite (Gt) composites (OMS-2/Gt) were prepared by a facile refluxing approach. The structure and morphology of the obtained materials were systematically investigated. The results reveal that OMS-2 nanofibers are uniformly dispersed on the surface of Gt, and the ratio of Mn3+ species in OMS-2 increases lineally with the increase of Gt dosage. The catalytic activity of OMS-2/Gt was evaluated by the degradation of Acid Orange 7 (AO7) in the presence of peroxymonosulfate (PMS). It is found that the OMS-2/Gt composites show enhanced catalytic performance with the degradation rate lineally correlated with the content of OMS-2 in the catalyst, and even with the ratio of Mn3+/Mn4+. XPS and radical scavenger experiments further indicated that the oxidation of Mn3+ by PMS system occurs in the system with the formation of hydroxyl radicals contributed to the dye degradation. The catalysts also exhibit good stability and reusability during consecutive cycles. Thus, the environmental friendly OMS-2/Gt composites with low cost, facile synthesis process and high efficiency are very promising catalysts for PMS activation and pollutants degradation.