Sustainable activation of peroxymonosulfate by the Mo(IV) in MoS2 for the remediation of aromatic organic pollutants

Abstract

Although MoS2 has been proved to be a very ideal cocatalyst in advanced oxidation process (AOPs), the activation process of peroxymonosulfate (PMS) is still inseparable from metal ions which inevitably brings the risk of secondary pollution and it is not conducive to large-scale industrial application. In this study, the commercial MoS2, as a durable and efficient catalyst, was used for directly activating PMS to degrade aromatic organic pollutant. The commercial MoS2/PMS catalytic system demonstrated excellent removal efficiency of phenol and the total organic carbon (TOC) residual rate reach to 25%. The degradation rate was significantly reduced if the used MoS2 was directly carried out the next cycle experiment without any post-treatment. Interestingly, the commercial MoS2 after post-treated with H2O2 can exhibit good stability and recyclability for cyclic degradation of phenol. Furthermore, the mechanism for the activation of PMS had been investigated by density functional theory (DFT) calculation. The renewable Mo4+ exposed on the surface of MoS2 was deduced as the primary active site, which realized the direct activation of PMS and avoided secondary pollution. Taking into account the reaction cost and efficient activity, the development of commercial MoS2 catalytic system is expected to be applied in industrial wastewater.