SEM/TEM Study of Zeolite Crystallization

本研究项目旨在了解分子筛沸石在水热体系中的结晶机理。在沸石合成中利用种子技术可以得到更大的颗粒，正如预期和期望的那样，但成功的程度有限，并且种子晶体本身转化为具有相当不规则形态的多晶团块。这个正在进行的项目继续沸石合成研究，以调查种子沸石结晶系统的影响，并研究对种子晶体本身的影响。虽然已经获得了初步繁殖发生在有籽硅石合成系统中的间接证据，但正在尝试通过显微技术实际观察这些情况。也有人试图证明一些沸石系统的这些表面结合的初始繁殖核保留在种子晶体表面并产生上述多晶质量。尝试用扫描电镜和透射电镜对这些初始繁殖核进行检查。不同的生长环境对种子晶体本身的影响的研究是通过这些技术和选定的区域衍射技术完成的。在结晶过程中使用后期试剂添加技术生长的晶体也进行了研究。最后，对沸石晶体析出物NaA沸石和“硅石”进行了研究。这些晶体在传感器和膜分离中有潜在的应用。

This research program deals with understanding of the mechanisms of crystallization of molecular sieve zeolite in hydrothermal systems. Taking advantage of seeding techniques in zeolite syntheses results in somewhat larger particles, as expected and desired, but the degree of success has been limited, and the seed crystals themselves are converted into polycrystalline masses with quite irregular morphology. This ongoing project continues the zeolite synthesis research to investigate the effects of seeding zeolite crystallization systems, and to study the effects on the seed crystals themselves. While circumstantial evidence that initial breeding occurs in the seeded silicalite synthesis system has been obtained, an attempt to actually observe these by microscopic techniques is being made. An attempt is also being made to demonstrate for several zeolite systems that some of these surface-bound initial bred nuclei remain on the seed crystal surface and generate the polycrystalline masses noted above. Examination of these initial bred nuclei by scanning and transmission electron microscope is attempted. An investigation of the effects that different growth environments have on the seed crystals themselves is done by these techniques and by selected area diffraction techniques. Crystals grown using the technique of late reagent addition during a crystallization also are investigated. Lastly, zeolite crystal precipitate zeolite NaA and "Silicalite" are investigated. The crystals have potential applications in sensors and in membrane separations.