锌铝水滑石对亚甲基蓝光催化降解性能

摘要

ZnAl Layered double hydroxides (Zn3Al-LDHs) with Zn/Al molar ratio of 3:1 was synthesized by the coprecipitation method. The photocatalysts were characterized by powder X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectroscopy(UV-Vis DRS) and TG-DTA. The effect of the catalyst amount, illumination time was studied on the photocatalytic degradation methylene blue. The results show that the optimum catalyst amount and the illumination time is 150～200 mg, 120 min, respectively. After 180 min irradiation, the absorption peak of methylene blue solution disappears with a degradation rate of 95% due to the breaking of the chormophoric group. In addition, the degradation kinetics can be described by the first-order kinetic function as suggested by degradation mechanism and the dynamics of the process.%采用共沉淀法制备了物质的量的比为3∶1的锌铝水滑石(Zn3Al-LDHs),并用X射线粉末衍射(XRD)、紫外-可见漫反射光谱(UV-Vis DRS)和热重-差热(TC-DTA)等技术对催化剂的结构和性质进行表征.考察了不同催化剂投入量、光照时间等因素对锌铝水滑石降解亚甲基蓝(Methylene Blue)的影响,找到了最佳的催化剂用量为150～200 mg,光照时间为120 min.在最佳实验条件下,光照180 min后亚甲基蓝的特征峰消失,发色基团破坏,其降解率达到了95％左右.此外,通过探讨光催化过程动力学及降解机理,表明该降解反应符合一级反应动力学模型.