中文摘要：

硅藻土是一种天然生物成因的SiO2．采用硅藻土做载体，用溶胶一凝胶法制备TiO2／硅藻土复合光催化剂，TiO2呈薄膜状负载在硅藻土上，部分团聚成颗粒状．在紫外光条件下负载TiO2硅藻土对亚甲基蓝具有良好的光催化降解性能，36h后对亚甲基蓝的脱除率为90％，48h达到98％，降解效果好．纯硅藻土48h后对亚甲基蓝的脱除率仅为35％左右．负载TiO2硅藻土对亚甲基蓝的光降解性能受TiO2的同质多像结构影响．随着锐钛矿含量增加，负载TiO2硅藻土的光降解性能增强．但是，当温度进一步升高，TiO2由锐钛矿型转化为金红石型，负载TiO2硅藻土的光降解性能随之降低．添加H2O2明显提高亚甲基蓝溶液的降解效果．

英文摘要：

TiO2-mounted diatomite photocatalysts were prepared by a sobgel method with diatomite support, a kind of natural biological diatomaceous silica earth. SEM observation shows that TiO2 is well mounted on the surface of diatomite as films and some particles. TiO2-mounted diatomite decomposes efficiently methylene blue （MB） under UV irradiation. Within 36h irradiation, about 90% MB is decomposed by TiO2/diatomite photocatalyst. After 48h irradiation, MB is decomposed almost completely （about 98%）. However only 35% MB is decomposed by pure diatomite after 48h irradiation. With the increasing heat-treatment temperatures, the photocatalytic activity of the TiO2/diatomite is increased with the formed anatase type of TiO2 increasing, but decreased with rutile type of TiO2 formed at 700℃ and 900℃. Adding H202 in MB solution can improve the efficiency of the TiO2- mounted diatomite photocatalysts greatly.