Visible-light-driven MIL-53(Fe)/BiOCl composite assisted by persulfate: Photocatalytic performance and mechanism

The novel semiconductor heterojunction of MIL-53(Fe)/BiOCl composite was first prepared through the solvothermal reaction. The prepared materials were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunner-Emmet-Teller (BET) and ultraviolet-visible diffuse reflectance spectroscopy (DRS). MIL-53(Fe)/BiOCl heterojunction is a kind of photoexcited materials and it accelerates the photoreactivity of BiOCI under the visible light irradiation. It was used to remove Rhodamine B (RhB) with the existence of persulfate (PS). The UV-vis spectrophotometer and the TOC detector show that the degradation rate and TOC removal efficiency of RhB (20 mg/L) are 99.5% and 69.4%within 30 min visible-light irradiation, respectively. Due to the proper band gap of material and the presence of electron acceptor, PS, the survival time of active radicals are increased. The active species h(+), center dot SO4- and center dot OH are found to play the important roles during the reaction system. The possible mechanism for the RhB degradation of MIL-53(Fe)/BiOCl/PS is also proposed. Furthermore, the results of the material reusability for the degradation of RhB indicate that the MIL-53(Fe)/BiOCl has a good stability and can be used in the environmental water sample treatment.