Efficiently activate peroxymonosulfate by Fe3O4@MoS2 for rapid degradation of sulfonamides

Abstract

By coating with MoS2 on the surface of Fe3O4 nanoparticles, a series of Fe3O4@MoS2-X catalysts were successfully synthesized to activate peroxymonosulfate (PMS) for sulfonamides (SA) degradation. Owing to the highly active Mo(IV) could efficiently improve the Fe(II)/Fe(III) cycle, the activity of the heterogeneous reaction was significantly enhanced. Compared with Fe3O4/PMS system, the degradation efficiency of SA in Fe3O4@MoS2-3/PMS system was improved by 4 times and the degradation kinetic rate was improved by 86 times. In addition to SA, Fe3O4@MoS2-3/PMS system also showed high efficiency in treating other representative emerging pollutants (phenols, endocrine disrupting chemicals, drugs or antibiotics). Fe3O4@MoS2-3/PMS is a system in which Fe3O4 and MoS2 are both active components. The main active free radical in Fe3O4@MoS2-3/PMS system is SO4•-, the generation of HO• may be suppressed after coating MoS2. Meanwhile, exposed Mo(IV) on the surface of MoS2 participates in the reduction of Fe(III) and further promotes the reaction rate. Furthermore, Mo(VI) participates in the generation of non-radical 1O2 which is also an important reactive oxygen species in the system. Fe3O4@MoS2-3 could be applied in a wide initial pH range (3.0 ~ 9.0). Anions (Cl-, NO3− and SO42−) and natural organic matter (humic acid, HA) had little effect on the degradation efficiencies of Fe3O4@MoS2-3. This study provides theoretical and experimental basis for the development and utilization of Fenton-like reaction catalysts.