Effects of operating parameters on photocatalytic degradation of methylene blue or phenol on supported titanium-based catalysts

Photocatalytic decompositions of both methylene blue and phenol in aqueous solutions were conducted separately on titanium-based catalysts. The catalysts were prepared using impregnation method on different supports (SiO₂, Al₂O₃ or ZSM-5) and titanium precursors (TiO₂ or TiCl₄). They were tested in visible light or UV irradiations of different wavelengths (254 and 365 nm). The physico-chemical characteristics of the catalysts were obtained using BET, XRD, FTIR and TGA. The supports surface areas and porosities showed insignificant decreased after impregnation with the active components. The diffraction patterns showed strong peaks that are assigned to titania anatase phase and weaker peak that indicated low concentration of rutile phase. Irrespective of the support, FTIR showed broad peaks of Ti-O-Ti linkages in TiO₂ particles. The catalysts were found to be active in decomposition of either methylene blue or phenol from aqueous solutions. For both methylene blue and phenol, the removal trend is TiO₂/SiO₂<TiO₂/Al₂O3<<TiO₂/ZSM-5.