Photocatalytic Degradation of Methyl Orange Over Y3+ Doped TiO2 Pillared Montmorillonite

Y3+ doped TiO2 pillared montmorillonite (denoted by Y-Ti-Na-MMT) was prepared by acid sol method using montmorillonite (Na-MMT) as the carriers. The catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), differential thermal analysis (TG), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectra (DRS). The results showed that Y-Ti-Na-MMT had the best layer structure, the crystal type of TiO2 nanoparticles was anatase and the introduction of Y3+ could inhibit the growth of TiO2 nanoparticles. The BET special surface area of Y-Ti-Na-MMT was 5.90 times of Na-MMT and 1.19 times of TiO2 pillared montmorillonite (Ti-Na-MMT). Compared with Ti-Na-MMT, the band gaps of Y-Ti-Na-MMT calculated from cut-off wavelength decreased from 2.9 eV to 2.5 eV, exhibiting the higher light absorption. Y-Ti-Na-MMT was tested for photocatalytic degradation of methyl orange (MO) and it was more efficient in MO removal, in comparison with Ti-Na-MMT and TiO2. The calculated pseudo-first-order constants (Kr) were in the order of Y-Ti-Na-MMT (0.0147 min(-1)) > Ti-Na-MMT (0.0074 min(-1)) > TiO2 (0.0027 min(-1)). The TOC removal rate increased to 39% for Y-Ti-Na-MMT. The reusing tests proved that Y-Ti-Na-MMT was stable, reusable and durable in degradation of MO.