摘要
以多孔硅胶作载体,通过酸性溶胶法制备了TiO2/SiO2催化剂。采用X射线衍射(XRD)、热重—差热分析(TG—DTA)、扫描电镜(SEM)和BET等方法对该催化剂进行了表征。以偶氮染料酸性橙7(AO7)的可见光降解作为探针反应,研究了TiO2/SiO2的催化活性。结果表明,TiO2的平均晶粒尺寸为5.1nm,晶型为锐钛矿;TiO2/SiO2具有大的比表面积,比P-25催化剂具有更高的光催化活性和更好的沉降性能,便于回收利用。
The TiO2/SiO2 （31% TiO2 hy weight） catalyst was prepared by the acid-catalyzed sol method from the base silica gel; both were characterized by XRD, TG/DTA, SEM, and BET. The loading of TiO2 reduced the base gel＇s specific surface area （from 347 m2/g to 225 m2/g ）, with most reduction in meso pores, and its average pore size （from 9.0 nm to 6.8 nm）, while the silica base stabilized the crystalline structure of TiO2. The new catalyst was an effective adsorbent as well as a powerful catalyst. In a comparative study of adding 2 g the TiO2/SiO2 and P-25 （a commercial TiO2 ） to each of 1 L of 80 mg/L solution of AO7 （an azo dye）, adsorption on TiO2/SiO2 during the 1 h of contact in dark resulted in 41.5% reduction in AO7 vs. 15.5% reduction by adsorption on P-25; the first order reaction rate constant of the photodegradation taking place during the next 13 h of contact under visible light was 0. 278 h-1 for the TiO2/SiO2 and 0. 116 h-1 for P-25. The base silica gel was not effective as a catalyst. The pho- todegradation was initiated by the adsorption of energized AO7 molecules on the catalyst. The TiO2/SiO2 catalyst set- tled readily and was easily collected for reuse.
出处
《环境污染与防治》
CAS
CSCD
北大核心
2008年第9期46-50,共5页
Environmental Pollution & Control
基金
宁波市博士基金资助项目(No.2005A610029)
浙江省教育厅项目(No.20061645)
