Immobilization of TiO₂ films on activated carbon fiber and their photocatalytic degradation properties for dye compounds with different molecular size

A series of TiO₂/ACF samples were prepared by sol-gel-adsorption method and were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and nitrogen adsorption. SEM showed that calcined temperature had an important influence on final structure morphologies of TiO₂ films. XRD analysis implied that all samples presented anatase structure, carbon surfaces located under TiO₂ film could influence the crystalline degree of TiO₂. Nitrogen adsorption measurement indicated that some pores located in activated carbon fiber (ACF) were covered by TiO₂ film. Photocatalytic degradations of methyl orange solution and acid fuchsine solution showed that dye compounds could be removed rapidly from water by TiO₂/ACF samples because of dual functions: absorption of ACF and photocatalytic degradation of TiO₂ film, and there was a matched relation between pore diameter of immobilized sample and molecular size of dye compound.