TiO2/膨润土光催化降解有机污染物

用溶胶-凝胶法制备了一系列TiO2/膨润土光催化剂(不同负载量和不同焙烧温度), 以罗丹明B(RhB)为模型化合物, 通过测定染料吸光度和体系化学需氧量(COD)变化, 来研究它们在紫外光照射下降解有机污染物的性能. 评价结果表明, 负载量为50%和焙烧温度为400 ℃的催化剂Ti400样品降解RhB活性较好, 虽然其矿化活性略小于P25(光照4 h P25的COD变化为99.7%, 400 ℃焙烧的TiO2/膨润土催化剂Ti400的COD变化为97.0%), 但是TiO2/膨润土催化剂更易于回收再利用. 用Ti400做催化剂降解RhB, 连续循环使用7次, 其催化活性基本不变. 用XRD、BET和紫外可见漫反射(UV-Vis DRS)等方法对这些催化剂进行了表征. 表征结果表明催化剂比表面积大有利于催化活性的提高.

Photocatalytic Degradation of Organic Pollutants on TiO2/Bentonite

A series of TiO2/bentonite catalysts (with different loadings and calcined at different temperatures) were prepared by sol-gel method. The prepared catalysts were employed to photocatalytically degrade organic dye Rhodamine B (RhB) under UV irradiation. The capabilities to degrade organic pollutants were studied by detecting the change of their absorbance and chemical oxygen demand (COD) under UV light irradiation. The results showed that they had a better catalytic reactivity when the loading was 50% and calcination temperature was 400 ℃ (Ti400). Their minerialization activity was slightly less than P25, when UV light irradiation time was 4 h, COD changes of P25 and TiO2/bentonite calcinated at 400 ℃ were 99.7% and 97.0%, respectively. But they were easier to be reused. Ti400 catalyst was employed to degrade RhB, and its photocatalytic activity was kept almost the same after recycling 7 times. The catalysts were further characterized by XRD, BET, and UV-Vis DRS. The experimental results showed that they would have a better activity when their BET surface area was larger.