Photocatalytic Oxidative Desulfurization of Dibenzothiophene on TiO2 Modified Bimodal Mesoporous Silica

By using the bimodal mesoporous silica(BMMS) as the carrier and butyl titanate as the titanium source, the TiO2/BMMS catalyst was prepared. The samples were characterized by XRD, XRF, N2 adsorption and desorption, FTIR, UVvis, SEM, EDS, and TEM techniques. The test results showed that TiO2 was amorphous, the TiO2/BMMS catalyst had an ordered bimodal mesoporous structure, and the chemical interaction existed between BMMS and TiO2. Since the TiO2/BMMS had a lower band gap, its photocatalytic activity was better than TiO2. Under UV irradiation a one-pot PODS system was set up, using TiO2/BMMS as the catalyst, H2O2 as the oxidant, and methanol as the solvent. The TiO2/BMMS catalyst showed better photocatalytic activity than the mono-modal mesoporous TiO2/SBA-15 catalyst, and the desulfurization rate of dibenzothiophene (DBT) over TiO2/BMMS catalyst could reach 99.2%. The TiO2/BMMS catalyst also had so good stability that the desulfurization rate of DBT did not drop apparently after 8 cycles of reusing, and could still be close to 90%.