Novel double Z-scheme g-C₃N₅/BiFeO₃/ZnIn₂S₄ heterojunction system with enhanced visible-light-induced photo-Fenton activity towards sulfamethoxazole degradation

In this study, a novel double Z-scheme g-C₃N₅/BiFeO₃/ZnIn₂S₄ (CBZ) heterojunction nanocomposite was synthesized using a simple wet chemical process. The crystal structure, morphology, optical, and chemical compositional behaviors of the prepared nanocomposite were characterized using various techniques. The Vis/H₂O₂/CBZ-40% system could remove 97% sulfamethoxazole (SMX) pollutant for 60 min. The significantly enriched performance was attributed to the greater Fe²⁺/Fe³⁺ conversion efficiency by decomposing H₂O₂, and the synergistic coupling of the CBZ-40% in ternary heterojunction provided a better charge transfer pathway for the initiation of photo-Fenton reactions. In addition, the trapping experiments and electron spin resonance analysis identified active reactive oxygen species such as ^•OH, ^•O₂⁻, and ¹O₂. The possible degradation mechanism of SMX and their intermediate products were proposed based on the above experimental analysis. Moreover, this results showed the suitability of using Vis/H₂O₂/CBZ-40% system, providing excellent reusability and an admissible platform for wastewater remediation via double Z-scheme heterojunction.