伊利石绿色合成多级孔ZSM-5沸石分子筛催化剂

Yanbian Korean Autonomous Prefecture has rich illite resources, and the development of value added zeolite products is one of the prior projects of local government. Green synthesis of industrially important ZSM-5 catalyst by using local illite as cheap raw materials are meaningful research work in the viewpoints of science and economics. In the present research, illite will be treated at high temperature, and followed by acid treatment to prepare aluminium containing active silica residue. The transformation mechanisms of crystal phase and changes in chemical compositions will be studied in order to achieve simultaneous dealumination and potassium extraction. Based on these studies, a green pretreatment approach will be suggested to obtain high silica to alumina ratio zeolite synthetic precursor from illite clay. In the present research, composite microspheres will be prepared through spray drying the mixture of synthetic precursor, nitrogen containing nature polymer (adhesive), and organic template or zeolite seeds, followed by steam assisted in situ crystallization process to synthesize highly crystalline ZSM-5. Through studying the process of in situ carbonization of polymers and in situ crystallization of hierarchical ZSM-5 will be discovered. These studies will provide a green method for controlled synthesis of hierarchical ZSM-5 catalyst. In the present research, through the studies of the acidity characterization and reactivity evaluation in toluene disproportionation reaction, the mechanism of mass diffusion in the hierarchical pores and shape selectivity in the micropores will be discovered, finally will provide a new method for the synthesis of highly active ZSM-5 catalyst by using illite clay.

延边州伊利石资源丰富，高附加值沸石分子筛的开发是本地区伊利石产业优先发展主题之一。以本地廉价伊利石为原料，进行工业催化剂ZSM-5沸石分子筛的绿色合成具有重要的科学意义和经济价值。本研究中，伊利石经高温活化和酸浸处理，制备含铝活性氧化硅伊利石渣料，探究伊利石层状晶体结构和化学组成的变化规律，实现同步脱铝和释钾，提供伊利石至高硅铝比的分子筛合成原料的绿色处理方法。本研究中，以伊利石渣料为硅铝原料，含氮天然物高分子为粘结剂，添加有机模板剂或沸石分子筛晶种，采用喷雾干燥法制备复合微球，并经蒸汽辅助原位晶化，合成高结晶度ZMS-5沸石分子筛；通过探究复合微球的原位晶化和碳化过程，揭示分子筛固相晶化和氮掺杂碳模板作用机理；通过甲苯歧化反应性能评价，揭示多级孔结构中物料扩散和微孔中择形催化机理，为伊利石粘土制备高活性ZSM-5沸石分子筛催化剂提供绿色合成方法。

本项目研究以制备"伊利石绿色合成多级孔ZSM-5沸石分子筛催化剂"为研究目的，具体包括（1）伊利石黏土的纯化、其钾、铝组分的提取、（2）伊利石基多级孔ZSM-5分子筛的绿色合成、（3）评价相关产物的在甲苯歧化反应中的催化性能与优化等内容。在本项目的研究过程中，按计划完成研究目的：首先，利用高温熔盐、高温活化-水热酸浸等工艺，成功实现了对伊利石中铝，钾元素高效率提取（提取率高于95%），并采用动力学分析了元素的溶出过程。其次，以伊利石提钾、铝元素后获得的高硅铝前驱体为原料，在外加铝源的情况下，先后采用晶种辅助-类固相蒸汽辅助技术；无溶剂、无模板合成技术，制备了具有高结晶度的亚微米ZSM-5沸石分子筛，通过对分子筛晶体的生长动力学研究，对伊利石基ZSM-5沸石分子筛的晶化过程进行了深入探究，为绿色合成沸石催化剂提供一种有效途径。最后，采用甲苯歧化反应为探针，对其催化性能进行了系统的评价，证实以伊利石基高硅前驱体合成的 ZSM-5 沸石分子筛的催化能力于工业沸石相当。本项目的研究成果将对伊利石黏土资源的高附加值利用以及工业上以黏土为原料，绿色制备沸石分子筛催化剂等方面起到一定的推进作用。