MoS2 boosts the Fe2+/PMS process for carbamazepine degradation

Activation of peroxymonosulfate (PMS) by Fe2+ is a green oxidation process for degradation of organic contaminants. However, the formation of iron mud and low PMS utilization lead to the decreased oxidation efficiency. In this work, commercial MoS2 particles were used as the catalyst for boosting the Fe2+/PMS process for carbamazepine (CBZ) removal. The CBZ removal efficiency by the MoS2/Fe2+/PMS process was significantly enhanced, increasing to 6.5 times that of the Fe2+/PMS process. The Fe3+ was reduced to Fe2+ by the exposed Mo4+ on the surface of MoS2, leading to the enhanced PMS utilization rate and increased Fe2+ concentration. The relative intensity of DMPO-HO• and DMPO- SO4–• followed the order of MoS2/PMS < Fe2+/PMS < MoS2/Fe2+/PMS, also suggesting the enhanced oxidation activity with the addition of MoS2 in the process of Fe2+/PMS. The commercial MoS2 had good stability shown by the CBZ removal efficiency remaining almost unchanged during 8-time cycling use. Finally, a possible CBZ degradation pathway was proposed for helping understand the oxidation mechanism of the MoS2/Fe2+/PMS process.