微米级负载型TiO2催化剂在光催化-膜分离反应器中的应用

基于光催化．膜分离三相流化床反应器的结构特点及膜分离特性，以微米级MCM-41分子筛为载体，采用原位生成法制备微米级负载型TiO2催化剂。针对微米级负载型TiO2催化剂在光催化一膜分离反应器中的分布特性、悬浮特性、分离特性及膜污染特性进行研究。结果表明，曝气量一定的情况下，微米级负载型TiO2催化剂在光催化一膜分离反应器中具有良好的悬浮特性，且优于纳米TiO2。随着催化剂投加量的增加，悬浮浓度也随之增加。光催化反应器底部曝气0．3m。／h、催化剂投加量为1g／L时为宜。膜分离器中催化剂悬浮浓度明显低于光催化反应器；该微米级催化剂与纳米TiO2相比具有不粘附、不堵塞膜孔等优良特性，能够有效降低膜污染，延长分离膜使用寿命。膜底曝气为0．1m3／h时，反应器连续运行5h（未加反冲洗）后，微米级负载型TiO2催化剂和纳米TiO2对膜组件的污染程度分别为膜通量衰减率4．3％和37．4％。反应器连续运行72h，膜组件依然具有很好的分离特性。

Application of micron-scale supported TiO2 catalysts in photocatalysis-membrane reactor

Based on the structural features and membrane separation characteristics of photocatalytic-mem- brane separation reactor, we prepared the micron-scale supported TiO2 catalysts via pore-situ hydrolysis method using MCM-41 as the carrier. The distribution characteristics, suspension characteristics, separation properties and membrane fouling characteristics of the micron-TiO2 in the reactor were studied. Results showed that the sus- pension characteristics of this micron-TiO2 were better than nano-Ti02 at the same aeration rate. The suspension concentration increased with the amount of catalysts. The appropriate conditions were aeration of 0.3 m3/h and catalyst dosage of 1 g/L. The concentration of suspended catalyst in the membrane separator was significantly lower than that in the photocatalytic reactor. Compared with nano-TiO2, the micron-TiO2 won＇t clog the mem- brane pores and effectively reduce membrane fouling to extend service life of the separation membrane. With the conditions of bottom aeration of 0.1 m3/h and continuous running for 5 h without backwash, the membrane flux decay rates were 4.3% and 37.4% corresponding to the membrane module contamination evoked by micron- TiO2 and nano-TiO2,respectively. The membrane module still had good separation performance after the reactor ran for 72 h continuously.