TiO_2/ACF复合材料的Sol-Gel法制备及其对苯的去除性能

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

以钛酸四丁酯为钛源,采用改进溶胶-凝胶法合成TiO2前驱体;采用浸渍-提拉法将TiO2前驱体负载在活性炭纤维(ACF)表面制得TiO2/ACF复合材料.采用X射线衍射(XRD)、扫描电镜(SEM)、低温液氮吸附等对TiO2/ACF复合材料晶相结构、表面结构等进行了表征.在静态自制光催化反应装置中紫外光照射条件下,以高浓度(2926.5mg/m3)气态苯考察TiO2/ACF对气相有机污染物的去除性能,以气相色谱-质谱(GC-MS)检测中间产物种类与分布.结果表明:TiO2于ACF表面形成完整薄层,随负载次数增加,TiO2/ACF比表面积下降;TiO2薄层变厚、开裂,甚至脱落.400℃煅烧时TiO2已完全转变为锐钛矿相,随煅烧温度升高,锐钛矿型TiO2晶粒尺寸变大,至700℃时开始有金红石相生成.负载2次,400℃煅烧TiO2/ACF复合材料TiO2/ACF-400-2表现出最高活性.TiO2/ACF对苯的去除过程中未检测到毒性较大的酚、醌类中间产物.

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 mode/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 transforma- tion 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 caleinated 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.