One-pot solvothermal synthesis of BiOI/Bi₂WO₆/MXene composites for efficient photocatalytic degradation of ranitidine

BiOI/Bi 2 WO 6 /MXene composite was successfully synthesized via a solvothermal method, confirmed by XPS/XRD. • Optimal composite degraded 89.3% ranitidine and mineralized 56.0% in 2 h. • EPR analysis indicated that superoxide radicals (•O₂ − ) dominate the degradation process. Ranitidine, a widely used acid-suppressing drug, can undergo nitrosation in aquatic environments to generate N -nitrosodimethylamine (NDMA), a potent carcinogen that poses a serious threat to aquatic ecosystems. To address its persistence against natural degradation, a ternary BiOI/Bi₂WO₆/MXene composite was fabricated via a one-pot solvothermal synthesis. Heterojunction construction effectively broadened its visible-light harvesting capacity. Characterizations by SEM, TEM, XRD, and UV–Vis DRS confirmed the successful formation of the heterojunction with markedly enhanced visible-light absorption. Combined with band structure analysis and radical trapping experiments, a Z -scheme charge transfer mechanism was proposed. Visible-light photocatalytic tests showed that the optimal sample exhibits a high degradation efficiency of 89.3% for RAN, with a 47% relative enhancement compared with pristine BiOI. Radical identification revealed that superoxide radicals (·O₂ − ) were the dominant reactive species. The synergistic effect between the electron-conductive MXene and the interfacial heterojunction accelerated photogenerated carrier separation and ·O₂ − production. Moreover, the composite retained 72.35% of its degradation efficiency after three cycles, demonstrating good stability. This work provides a novel material design strategy for visible-light-driven ranitidine degradation and offers a theoretical basis for mitigating NDMA formation risks.