Abstract: For treatment of antibiotic wastewater, the combined effect of semiconductor photocatalysis and sulfate radical (SO^-₄·)-based advanced oxidation processes is considered as a potential solution. Herein, 3D bismuth molybdate (Bi₂MoO₆) microspheres were prepared via a facile solvothermal method and applied to activate peroxymonosulfate (PMS) for tetracycline hydrochloride (TC) elimination under visible light irradiation. The morphology, crystal lattice structure, optical performance, and other properties of the Bi₂MoO₆ sample were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). The result show that the 3D Bi₂MoO₆ microspheres with a size of ~1.5 mm are composed of Bi₂MoO₆ nanosheets with a thickness of ~20 nm. Bi₂MoO₆ microspheres exhibite high adsorption capacity and significantly photocatalytic performance for the degradation of TC under visible light illumination. Meanwhile, the addition of PMS enhances the ability of Bi₂MoO₆ microspheres for the degradation of TC under visible light illumination. The effects of catalyst dosage, PMS concentration, co-existing ions, such as chloride (Cl^-), carbonate (CO^2-₃) and nitrate (NO^-₃), and humic acids (HA) on the degradation of TC by Bi₂MoO₆ activated PMS under visible light irradiation were investigated through static experiments. Radical trapping tests suggeste that hydroxyl radical (·OH), sulfate radical (SO^-₄·), peroxy radical (O^-₂·), and hole (h⁺) all play a important role in the degradation of TC. Finally, the detailed photocatalytic mechanism was also proposed.

Key words: Bi₂MoO₆, tetracycline hydrochloride, visible light irradiation, peroxymonosulfate, catalysis, degradation, radical