Coupling Bi₂MoO₆ with persulfate for photocatalytic oxidation of tetracycline hydrochloride under visible light

In this study, Bi₂MoO₆ nanosheets were fabricated by a facile hydrothermal method. The physicochemical properties and morphology of the as-prepared Bi₂MoO₆ nanosheets were characterized by XRD, XPS, DRS and FESEM technologies. Photocatalytic results indicated that the Vis/Bi₂MoO₆/PS system was much more efficient than Vis/Bi₂MoO₆ and Vis/PS individual binary systems in TC-HCl degradation. The effects of catalyst dosage (0–0.8 g/L), initial TC-HCl concentration (20–120 ppm), PS concentration (0–10 g/L), initial solution pH (2–10) and coexisting anions (Cl⁻, NO₃⁻, SO₄²⁻) on the TC-HCl removal efficiency were studied. Recycle experiments proved that the catalyst exhibited excellent stability and reusability in degrading TC-HCl molecules through activation of PS. In addition, trapping experiments revealed that SO₄^·− and h⁺ were the dominant radicals during degradation process. Finally, the possible mechanism for degrading TC-HCl in the Vis/Bi₂MoO₆/PS system was proposed.