Immobilisation of TiO2 films on activated carbon fibres by a hydrothermal method for photocatalytic degradation of toluene

To improve the degradation efficiency of TiO2 for low concentrations of volatile organic compounds, TiO2 loaded on activated carbon fibres (ACF) was prepared by an impregnation-hydrothermal method. The crystal structure, surface area, dispersion, optical absorption properties, and chemical composition of the TiO2/ACF composite materials were characterised by X-ray diffraction, Brunauer-Emmett-Teller analysis, scanning electron microscopy, ultraviolet-visible absorption spectroscopy, and X-ray photoelectron spectroscopy. The influence of the hydrothermal temperature, illumination time, space velocity, and light intensity on the photocatalytic activities of the TiO2/ACF composite materials was investigated with toluene as a model pollutant. The results showed that the phase of TiO2 was anatase, which was dispersed as a thin film on the ACF surface. The crystallinity, dispersion, UV absorption, and hydroxyl group content of TiO2 increased with an increase of hydrothermal temperature, whereas the photocatalytic activity of TiO2/ACF was maximised when the hydrothermal temperature was 180 degrees C. Increases in illumination time, space velocity, and light intensity were beneficial for regeneration of the composite materials. However, the energy efficiency decreased with increased light intensity. The degradation efficiency of toluene reached 40% with reaction conditions of illumination time: 3 h, space velocity: 1400 h(-1), and light intensity: 32 W. This degradation efficiency decreased 3.3% after recycling five times.