CdS/沸石分子筛复合光催化剂的制备及光催化性能

Preparation and Photocatalytic Properties of CdS/Zeolite Composite Photocatalysts

以煤矸石为原料,经Na_2CO_3碱熔活化和水热合成获得了沸石分子筛;利用Cd2+对沸石分子筛进行离子交换并通过沉淀过程制得了CdS/沸石分子筛复合粉体。采用X射线粉末衍射(XRD)和扫描电子显微镜(SEM)对所得样品进行表征,并以模拟太阳光为光源,罗丹明B(Rh B)为目标降解物,对其光催化活性进行了研究。结果显示:沸石分子筛上负载的CdS的晶相为立方相,制得的CdS/沸石分子筛复合粉体具有较好的光催化活性,且三次循环利用后仍具有较好的催化活性,在模拟太阳光辐照下,CdS/zeolite(0.5 M)复合粉体重复利用3次后,处理260 min对Rh B的降解率仍可达91.3%。所得粉体对Rh B的光催化过程符合一级动力学方程式,光催化过程中,Rh B紫外可见光谱的蓝移现象揭示所得CdS/沸石分子筛可通过脱乙基-共轭显色基团断裂途径降解Rh B。

The zeolite was synthesized by hydrothermal method after alkali fusion with coal gangue as raw material. CdS/zeolite composite powder was prepared by a precipitation process after ion exchange of Cd-（2＋） into the zeolite. The as-prepared sample was characterized by XRD and SEM. The photocatalytic activity of the as-prepared sample was evaluated by degradation of Rhodamine B（Rh B） under simulated sunlight condition. The results show that the crystal phase of the CdS coating zeolite is cubic phase structure. The CdS/zeolite composite powder exhibits an appreciable photocatalytic activity,and the powder still possesses high catalytic activity after being reused for three times. After the CdS/zeolite（0. 5 M） composite powder was reused for 3 times,the photocatalytic degradation of Rh B was still about 91.3% in 260 min under theirradiation of simulated sunlight. Photodegradation of Rh B by the as-prepared satisfied the first order kinetic equations. Blue shifts of Rh B ultraviolet-visible spectrum indicated its degradation through ethyl removal and conjugated groups break pathway.