Heterogeneous Photocatalytic Oxidation Removal of Gaseous Benzene over TiO_2/ACF Composite Prepared by Improved Sol-Gel Method

TiO2/ACF composite was prepared by improved sol-gel method using Ti(OBu)4 as titanium source.TiO2 precursor was loaded on activated carbon fiber(ACF) by dip-coating method.X-ray diffraction(XRD),scanning electron microscopy(SEM) and N2(77K) adsorption were used to characterize the obtained composite.High concentration gaseous benzene in a static-mode photocatalytic reactor was used as model compound for photocatalytic activity test.Gas chromatograph-mass spectrum(GC-MS) was used for intermediates identification.The results show that TiO2 can form perfect thin film on ACF surface.With the increase of dip-coating times,surface area of TiO2/ACF decrease,thickness of TiO2 film increase,then split and even fall off.Complete anatase can be formed for the sample calcinated at 400℃ and phase transformation of anatase to rutile occurrs at 700℃.The crystal size of TiO2 decrease with the increase of calcination temperature.The sample of TiO2/ACF-400-2 calcinated at 400℃ and dip-coated twice exhibits the highest activity for benzene removal.Intermediate analysis result reveals that no toxic of phenol and quinine compound is detected.