SiO_2负载的TiO_2光催化剂可见光催化降解染料污染物  

Degradation of Dye Pollutants on SiO_2-Supported TiO_2 Photocatalyst under Visible Light Irradiation

作　　者：王侃[1] 陈英旭[1] 叶芬霞[2] 

机构地区：[1]浙江大学环境工程系,浙江杭州310029 [2]宁波高等专科学校化工系,浙江宁波315016

出　　处：《催化学报》2004年第12期931-936,共6页

摘　　要：采用酸催化溶胶 凝胶法制备了SiO2 负载的TiO2 光催化剂 ,考察了制备条件对负载型TiO2 光催化剂的晶相、结构、比表面积和可见光催化活性的影响 .结果表明 ,采用SiO2 为载体时 ,TiO2 以纳米颗粒的形态分散在载体表面 ,负载型TiO2 /SiO2催化剂的比表面积大、等电点低而且热稳定性能良好 .偶氮染料酸性橙 7的可见光催化降解实验结果表明 ,染料污染物在催化剂表面的吸附是影响催化剂可见光催化活性的重要因素 .与试剂TiO2 样品相比 ,负载型TiO2 /SiO2 光催化剂具有更好的光催化活性和沉降性能 .Dye pollutants discharged from textile industries are the major sources of environmental contamination. The photodegradation of dye pollutants under visible light irradiation in the presence of TiO 2 catalyst is an excellent choice for the treatment of dye pollutants because of the effective utilization of solar energy, which is free and inexhaustible. SiO 2-supported titanium dioxide catalyst, TiO 2/SiO 2, was prepared by acid-catalyzed sol-gel method and characterized by XRD, N 2 adsorption technique and point of zero charge. The photocatalytic activity was evaluated by using the photodegradation of a textile azo dye, acid orange 7 (AO7), under visible light irradiation in aqueous medium. The results of XRD and N 2 adsorption technique showed that with the increase of the calcination temperature and the TiO 2 loading of TiO 2/SiO 2 catalyst, the average crystallite size of TiO 2 increased while its BET surface area decreased. No rutile phase of TiO 2 was formed in TiO 2/SiO 2 catalyst after calcination at high temperature, indicating that the presence of silica inhibited the phase transformation of TiO 2 from anatase to rutile. The photodegradation rate of AO7 under visible light irradiation depended strongly on adsorption capacity of the catalyst, and the photocatalytic activity of 31%TiO 2/SiO 2 catalyst was much higher than that of the pure TiO 2 catalyst sample. In addition, the supported TiO 2/SiO 2 catalyst had good sedimentation ability and tended to be effective in the treatment or pre-treatment of dye pollutants in aqueous systems.

关 键 词：二氧化钛 二氧化硅 光降解 可见光 染料污染物 酸性橙7 

分 类 号：X788[环境科学与工程—环境工程]