Fabrication Of V₂O₅/TiO₂-CNTs And Its Dechlorination Application

Chlorobenezes (CBs) are typical persistent organic pollutants (POPs), which are listed in Stockholm Convention as priority chemicals for eventual elimination. So it is necessarily to carry out study on the innovative and alternative to decompose CBs in industrial waste gas.In this paper, tetrabutyl titanate as raw material was used to prepare TiO2-CNTs composite support by sol-gel method; Then using impregnation method to V2O5/TiO2-CNTscatalyst. Preparation technology was optimized to synthesis an highly active catalyst. Then the paper systematically investigated the factors of catalytic efficiency, revealed the dechlorination mechanism.The main research contents and the results are as follows:Firstly, The surface modification and purification of CNTs was studied; The major factors investigated included HNO3 and H2SO4 treatment. Characterization and surface chemical properties of CNTs are analyzed by X-ray photoelectron spectroscopy (XPS), BET and other Characterization methods.The results shows that,surface impurities are removed, the ends of CNTs port is opened, the degree of graphitization is increasing, the-COOH,-OH and other active functional group is imported after oxidation by HNO3for 6hat 120℃Secondly, The preparation optimization of TiO2-CNTs composite supporters was studied; The major factors investigated included carbon nanotube content、calcination temperature、calcination atmosphere、dying method、 surfactant。Characterization and surface chemical properties of TiO2-CNTs are analyzed by BET、XRD and other Characterization methods; The results shows that, Carbon nanotube content is 5%, calcination temperature is 450℃ can prepare specific surface area, good crystallinity CNTs-TiO2 composite carrier. The surfactant can improve dispersion of TiO2-CNTs。Based on the TiO2-CNTs, the paper focus on the synthesis technology for V2O5/TiO2-CNTs catalyst; Explore the effect of vanadium content、heat treatmen and other process conditions for V2O5/TiO2-CNTs catalytic performance。The results shows that, The optimum preparaion condition of V2O5/TiO2-CNTs contains as follows:vanadium content 5%、ir atmosphere、 calcination temperature 450℃ time 4 h。Finally the activity of V2O5/TiO2-CNTs was evaluated; The research factors contains as follows:H2O content、O2 content、SO2 content HCBconcentrations and so on. The result shows that, the conversion of hexachlorobenzene was 90% at the optimum working condition. The degradation mechanism was also be researched. The rearch shows that,90% of HCB can be conversed by appropriate conditions. And the HCB was degrated into 1,2-Benzenedicarboxylic acid; 1,2-Benzenedicarboxylic acid was converted into 2-Ethylhexanal-.1-Octyn-3-o1,4-ethyl-, at last was degrated into CO2、CO、H2O.