Preparation of Z-Scheme BiVO₄/g-C₃N₄/PANI Heterojunction and Its Photocatalytic Degradation of Enrofloxacin

This study presents the synthesis and evaluation of a BiVO4/g-C3N4/PANI ternary heterojunction photocatalyst for the degradation of enrofloxacin (ENR) under visible light irradiation. The results demonstrate that the BiVO4/g-C3N4/PANI (10%) composite achieved a 91% removal efficiency of ENR within 120 min, following first-order kinetic behavior. Moreover, the photocatalyst exhibited stable degradation performance and maintained structural integrity after five consecutive cycles. The photocatalyst was characterized by XRD, SEM, TEM, FT-IR, XPS, and UV–vis DRS. The enhanced photocatalytic performance is attributed to the Z-scheme charge transfer mechanism facilitated by PANI, which enhances the separation of photogenerated carriers and reduces their recombination rate. Radical scavenging experiments and ESR spectroscopy confirmed that superoxide radicals (•O2–) and hydroxyl radicals (•OH) play dominant roles in the degradation process. Additionally, 15 degradation products of ENR were identified, and four major degradation pathways were proposed. The findings provide a theoretical basis for the application of this ternary heterojunction in environmental remediation and highlight its potential for efficient degradation of antibiotics.