Preparation of TiO2/porous glass-H with the coupling of photocatalysis oxidation–adsorption system in the initial position and its desulfurization performance on model fuel

Abstract

TiO₂/porous glass-H as composite catalysts were synthesized hydrothermally in the presence of H₂O₂ using porous glass microspheres as carriers. The photocatalytic-adsorptive desulfurization of model fuel by composite catalysts was investigated under UV irradiation. The structure and morphology of the composite catalysts were characterized via scanning electron microscopy (SEM), N₂ adsorption, X-ray diffraction (XRD) and ultraviolet-visible spectroscopy (UV-vis). The results showed that TiO₂/porous glass-H exhibited a significantly enhanced photocatalytic-adsorption desulfurization performance due to its enhanced surface area, highly enhanced light absorption, and reduced recombination of photogenerated electron pairs compared with TiO₂/porous glass synthesized in the absence of H₂O₂. The optimized TiO₂ loading was 20% and the reaction temperature was 303.15 K, which could achieve almost 100% sulfur removal when 0.1 g catalyst was applied to a sulfide concentration of 300 mg L⁻¹. Based on the kinetic fitting of the obtained data, it was found that the rate-controlling step of sulfide adsorption on the catalyst was a molecular diffusion process and the adsorption intensity and adsorption capacity of the composite catalyst were significantly improved compared with the porous glass-H in the adsorption thermodynamic curve, and ΔS, ΔH and ΔG of the adsorption process were calculated. In addition, TiO₂/porous glass-H could be regenerated via simple heat treatment, exhibiting similar efficiency as the original TiO₂/porous glass-H after three regeneration cycles.