Directional Separation of Highly Reductive Electrons to the Reactive Center in a Magnetic S-Scheme ZnFe2O4/A-MoS2 Heterojunction for Enhanced Peroxymonosulfate Activation toward Pharmaceuticals and Personal Care Product Removal

Promotedseparation of highly reactive electrons to ZnFe2O4 reactive center was achieved in S-scheme ZnFe2O4/A-MoS2, enhancing PMS activationfor PPCP degradation. Pharmaceuticals and personal care products (PPCPs) areubiquitousin sewage, adversely affecting ecosystems and human health. In thisstudy, an S-scheme magnetic ZnFe2O4/ammoniatedMoS(2) (ZnFe2O4/A-MoS2)heterojunction as a visible-light-driven PMS activator for PPCP degradationwas developed. ZnFe2O4/A-MoS2 achievesimproved photocatalytic activity because the construction of S-schemeheterojunction promotes the separation of the highly reductive photogeneratedelectrons. The optimized photocatalyst (10%-ZnFe2O4/A-MoS2, 0.2 g/L) achieved 100% removal of 2 ppmcarbamazepine (CBZ) within 2.5 min at a PMS dosage of 0.5 mM (initialpH 7.0). Mechanistic investigation revealed that the separated electronsto the ZnFe2O4 reactive center of the heterojunctionfacilitated PMS activation and generated SO4 (center dot-) as the dominant reactive species for CBZ degradation. The systemexhibited excellent practicability in various samples of actual sewage,where most sewage components negatively impacted CBZ degradation.Further, the chloride ions in high-salinity sewage could be activatedto generate additional reactive chlorine species for PPCP degradation.The heterojunction possesses outstanding reusability and stabilityin treating various water conditions. This work provides mechanisticand practical perspectives in developing novel S-type heterojunctionsfor recalcitrant pollutant treatment.