Xu Yin, Liu Tingjiao, Li Yang, Liu Yun, Ge Fei
Department of Environment, College of Environment and Resources, Xiangtan University, Xiangtan 411105, China.
Materials (Basel). 2018 Nov 27;11(12):2390. doi: 10.3390/ma11122390.
The nanostructure of ZnAl-layered double hydroxide (ZnAl-LDH) was designed to promote the catalytic performance of Mo-based ZnAl-LDH (Mo/ZnAl-LDH) catalysts, in a catalytic wet air oxidation (CWAO) process, under room temperature and pressure, in degradation of dye wastewater. Four most commonly used preparation methods, traditional precipitation (TP), hydrothermal synthesis (HS), sol-gel (SG), and urea co-precipitation (UC) were employed to prepare the ZnAl-LDH. The resulting Mo/ZnAl-LDH samples were contrasted through surface area, crystal structure, chemical state, and morphology. The degradation of cationic orchid X-BL, under room temperature and pressure, was developed to determine the catalytic activity of these Mo/ZnAl-LDH samples. The results showed that the nanostructure of ZnAl-LDH, prepared by HS, enhanced the adhesion of the catalytic active component, thus Mo/ZnAl-LDH had the highest catalytic activity of 84.2% color removal efficiency and 73.9% total organic carbon removal efficiency. Specific Mo species, such as Na₂Mo₂O₇, Mo dispersion, and O ions were proved to be related with catalytic performance. These findings preliminarily clarified that LDHs preparation methods make a difference in the performance of Mo/LDHs.
设计了锌铝层状双氢氧化物（ZnAl-LDH）的纳米结构，以提高钼基ZnAl-LDH（Mo/ZnAl-LDH）催化剂在催化湿式空气氧化（CWAO）过程中，在室温和常压下对染料废水的降解催化性能。采用四种最常用的制备方法，即传统沉淀法（TP）、水热合成法（HS）、溶胶-凝胶法（SG）和尿素共沉淀法（UC）来制备ZnAl-LDH。通过比表面积、晶体结构、化学状态和形态对所得的Mo/ZnAl-LDH样品进行对比。在室温和常压下，开展了阳离子桃红X-BL的降解实验，以测定这些Mo/ZnAl-LDH样品的催化活性。结果表明，通过水热合成法制备的ZnAl-LDH纳米结构增强了催化活性组分的附着力，因此Mo/ZnAl-LDH具有最高的催化活性，脱色效率达84.2%，总有机碳去除效率达73.9%。特定的钼物种，如Na₂Mo₂O₇、Mo分散度和O离子被证明与催化性能有关。这些发现初步阐明了LDHs的制备方法对Mo/LDHs的性能有影响。
