采用共沉淀法制备n( Zn)( Cr)为2的ZnCr水滑石,采用X射线粉末衍射仪( XRD)、紫外-可见漫反射光谱仪( UV-Vis)等方法对催化剂的结构和性质进行表征.通过可见光下对甲基橙的催化降解表征催化剂的活性.结果表明:制备的样品具有水滑石的结构,对可见光具有吸收性能. ZnCr水滑石具有良好的催化降解甲基橙性能,适宜的降解条件是甲基橙初始质量浓度不超过80 mg/L,催化剂用量为1 g/L,此条件下光照180 min后甲基橙的降解率达到了93. 58 %.动力学研究表明:该催化降解过程在甲基橙质量浓度低(≤20 mg/L)的条件下符合1级反应动力学模型,而在甲基橙质量浓度高(≥40 mg/L)的条件下符合0. 5级反应动力学模型.%ZnCr Layered double hydroxides with n(Zn)(Cr) molar ratio of 2 was synthesized by the coprecipitation method. The photocatalyst was characterized by powder X-ray diffraction( XRD) and ul-traviolet-visible absorption spectroscopy ( UV-Vis ) . The photocatalyst was evaluated by photocatalytic degradation of methyl orange under visible-light irradiation. The results showed that the prepared sample had a layered double hydroxides structure and visible-light absorption ability. ZnCr layered double hydrox-ides had better performance in degradation of methyl orange. The suitable condition for degradation was the concentration of methyl orange was not more than 80 mg/L,and the amount of photocatalyst was 1. 0 g/L. The methyl orange degradation of 93. 58 % could be obtained after the irradiation of 180 min at the above condition. The kinetic results indicated that the degradation process followed first-order kinetics at lower methyl orange concentration(≤20 mg/L) ,and half order kinetics at higher methyl orange concen-tration(≥40 mg/L) .
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