为提高可见光在降解染料废水过程中的利用率,以珍珠岩为载体,制备了负载型介孔TiO2催化剂.分析了焙烧时间和负载次数对催化剂降解亚甲基蓝性能的影响及其动力学规律,并用SEM扫描电镜进行了形貌表征.研究结果表明:焙烧时间超过1.5 h时,催化剂活性随焙烧时间的增加而降低,在最佳焙烧时间1.5 h的条件下,可见光对亚甲基蓝的降解率达71.59%;多次负载有利于催化剂活性的提高,其中负载3次的降解效果最佳珍珠岩呈现出疏松多孔结构,珍珠岩负载1次的二氧化钛较少;负载3次的较多,分布比较均匀;负载5次的二氧化钛较集中,但不及负载3次的多.所制备的催化剂降解亚甲基蓝反应都符合一级或准一级动力学规律,其中焙烧时间为1.5 h及负载次数为3次时的一级反应速率常数分别达到最高.
In order to improve the utilization rate of the visible light in the degradation of dye wastewater,the light expanded perlite(EP) was selected as the carrier for preparation of the mesoporous TiO2.The effects of the roasting time and load times on the degradation of methylene blue were examined.The kinetics of photocatalytic degradation of methylene blue was studied.The morphology was characterized by SEM techniques.The results showed that the activity of catalyst decreased with the increase of the roasting time which was over 1.5 h.Under visible light irradiation for 4 h,71.59% of methylene blue was removed over mesoporous TiO2/EP rosasted for 1.5 h.Repeated load was beneficial to improve the catalyst activity.The degradation of methylene blue were the optimisticest with loading 3 times.The EP showed a porous structure.Loading one time showed less TiO2on the EP.Loading 3 times showed more TiO2 relatively uniform distributed.The TiO2 was more concentrated with loading 5 times than 3 times.The photodegradation profiles of the methylene blue at different roasting time and load times were fit to the first or pseudo-order kinetics equations,in which the apparent reaction rate constants reached the highest level with rosasting 1.5 h and loading 3 times respectively.