Preparation of TiO₂@ZIF-8 for the removal of As(III) in water

To remove As(III) in water, the composite material of TiO₂@ZIF-8 was prepared by a sol-gel method with zeolitic imidazolate framework-8 (ZIF-8) as the matrix. The structure of TiO₂@ZIF-8 was characterized with scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The results indicated that the best loading efficiency of TiO₂ on ZIF-8 occurred when it was calcined at 300 °C for 3 h. This material was used to remove As(III) from aqueous solution, and the effect of the initial concentration of As(III), pH, and the illumination condition on the removal of As(III) was investigated. The results showed that the removal rate of As(III) was as high as 100% under a pH of 4–7, an initial As(III) concentration of less than 2 mg/L, and UV-light irradiation for 2 h. The repeated experiments were also performed for the investigation of the stability of TiO₂@ZIF-8.