Catalytic oxidation performance and ion-exchange of Ti-MWW zeolite membrane with dual organic template agents and potassium carbonate
Catalytic oxidation performance and ion-exchange of Ti-MWW zeolite membrane with dual organic template agents and potassium carbonate
复制标题
双有机模板剂和碳酸钾Ti-MWW沸石膜的催化氧化性能及离子交换性能
DOI：
10.1016/j.jcat.2022.12.022
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发表时间：
2022
影响因子：
7.3
通讯作者：
Hidetoshi Kita
中科院分区：
文献类型：
--
作者：
Yuan Liang;Shaoxiang Xu;Meihua Zhu;Jiamin Jiang;Jiao Zhang;Guobin Zhou;Na Hu;Xiangshu Chen;Hidetoshi Kita
以双有机模板剂和碳酸钾为模板剂，采用二次水热合成法，在不含硼酸的情况下，制备了管状Ti-MWW沸石膜。用TMAdaOH和HMI有机模板剂稳定了12MR笼和10MR分子筛的拓扑结构，K+离子是制备双层TiMWW沸石膜的关键矿化剂。此外，离子交换可以显著提高Ti-MWW沸石膜对苯酚与H_2O_2羟基化反应的催化性能，考察了铵盐、离子交换时间和温度对膜的微观结构和催化性能的影响。用0.5M(NH4)2SO4溶液在60℃下离子交换24小时，可使上层网状结构的Ti-MWW沸石层溶解和脱除，而位于莫来石载体上的Ti-MWW沸石层则保持不变。另一方面，离子交换可以促进六配位骨架钛物种向骨架内四配位钛物种的转变，部分钛分子筛的K+离子被NH4+离子取代。在50℃下，离子交换钛分子筛膜的总通量和苯酚转化率分别为14.89g·m−·h−1和36.49%。
In the absence of boric acid, the tubular Ti-MWW zeolite membranes are prepared with dual organic template agents and potassium carbonate by secondary hydrothermal synthesis. 12MR cage and 10 MR of the MWW zeolite topology structure is stabilized by TMAdaOH and HMI organic template agents, K+cations is a critical mineralization agent for preparing Ti-MWW zeolite membrane with bi-layer Ti-MWW zeolites layer in this work. Besides, ion-exchange could greatly improve the catalytic performance of the Ti-MWW zeolite membrane for phenol hydroxylation with H2O2, influences of ammonium salt, ion-exchange time and temperature on the micro-structure and catalytic performance are investigated. The upper network-like Ti-MWW zeolite layer could be dissolved and removed by ion-exchange with 0.5 M (NH4)2SO4solution at 60 °C for 24 h, and the “lying” Ti-MWW zeolites layer is kept on the mullite support. On the other hand, ion-exchange could promote the transformation of hexacoordinated extra-framework titanium species to tetracoordinated state in the framework, part of K+cations of Ti-MWW zeolites are replaced with NH4+cations. Total flux and phenol conversion of the ion-exchanged Ti-MWW zeolite membrane are 14.89 kg·m−2·h−1and 36.49 % for phenol hydroxylation by H2O2at 50 °C.