Abstract:Sulfate-modified titanium dioxide-bearing blast furnace slag (STBBFS) photocatalysts were prepared by the high energy ball milling method with (NH₄)₂SO₄ and titanium dioxide-bearing blast furnace slag (TBBFS) as raw materials. X-ray photoelectron spectroscopy(XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), UV-visible diffuse reflectance absorption spectra (UV-Vis), adsorption experiment and photocatalytic degradation measurement were conducted to characterize the structure, surface status, light absorption capacity, adsorption capacity and photocatalytic activity of the obtained photocatalysts. The adsorption equilibrium was described by the Langmuir isotherm model with a maximum adsorption capacity of 8.25 mg/g of Cr(VI) ions onto the STBBFS photocatalysts. As a result, sulfation of TBBFS improved the photocatalytic activities of STBBFS_x photocatalysts. At a low calcination temperature, the photocatalytic activity of STBBFS₃₀₀ photocatalyst was markedly higher compared with TBBFS_x prepared at high calcination temperature, indicating that the photocatalytic activity of STBBFS_x photocatalyst was determined by the balanced result between adsorption capacity and perovskite content.

Key words: sulfate modification; titanium dioxide-bearing blast furnace slag; Cr(VI); adsorption capacity; photocatalytic activity