NiFe2O4@MoS2 heterojunction induces the changes of PMS activation mode in PMS/Vis system for the directed generation of 1O2

Abstract

Peroxymonosulfate-based advanced oxidation is a promising approach for water treatment, but how to simply achieve the efficient PMS activation is still a great challenge. In this study, NiFe₂O₄@MoS₂ heterojunction was synthesized via hydrothermal method to achieve rapid degradation of sulfadiazine (SDZ) in the synergistic PMS/Visible light photocatalysis system (PMS/Vis). Almost complete elimination of sulfadiazine (SDZ) can be accomplished in 8 min (k_obs of 0.4038 min⁻¹), and forming a synergistic SDZ degradation mechanism including a predominant non-radical pathway (¹O₂) and complementary radical pathway (⋅O₂^–). The special heterojunction structure of NiFe₂O₄@MoS₂ could induce the directional separation of photogenerated carriers under visible light. Unlike the conventional transition metal-activated PMS process, the photogenerated electron-hole pairs of NiFe₂O₄@MoS₂ could serve as ceaseless PMS activator for ROS generation. The photocatalytic-assisted PMS system (PMS/Vis system) simultaneously solves the problems of variable metal cycling and ion solubilization in the traditional transition metal-activated PMS process, and enhances the material stability. LC-MS analysis identifies products and degradation pathways during SDZ reactions. Ecotoxicity assessment and total organic carbon results confirmed the degradation and mineralization of SDZ. This study shed light on the understanding of innovative heterostructured photocatalysts for enhanced PMS oxidation processes.