Application of Single Crystal Membrane (SCM) Technique for Investigation of Binary Diffusivities in Zeolites

CTS-9725256 O.talu Shah/克利夫兰州立大学首席研究员发展的单晶膜方法将用于研究二元体系的输运性质。同时，将致力于分子模拟，以加强对分子尺度现象的理解。所有工业应用最终都需要多组分平衡和扩散系数数据。因此，有必要开发从纯组分数据预测多组分平衡和扩散系数的方法。实验测量和计算机模拟对于开发可靠的预测模型是必不可少的。所选择的二元体系将是几种正构烷烃的混合物，它们的纯组分在硅沸石中的吸附平衡和扩散已经得到了很好的表征。将测量三种不同模式的二元扩散系数：1)共扩散，2)反扩散，以及3)只有膜结构才可能的新的层析模式。在另一组单独的实验中，将测量选定系统的二元平衡，以实现对扩散数据的准确解释。分子模拟将把现有的模拟技术扩展到一种新的稳态非平衡方法。这一方法将比以前更密切地补充实验测量，同时产生一种更有效的方法来得出准确的统计数据。这些发现将通过结合分子模拟和新颖的实验来解决困扰沸石研究进展的一些基本争议，从而填补目前对微孔中热力学和传输的理解的实质性空白。***

ABSTRACT CTS-9725256 O. Talu Shah/Cleveland State U. The single crystal membrane (SCM) method, developed by the principal investigator, will be applied to investigate transport properties of binary systems. In parallel, substantial effort will be devoted to molecular simulations to enhance the understanding of molecular scale phenomena. All industrial applications ultimately require multicomponent equilibrium and diffusivity data. It is therefore necessary to develop methods of predicting multicomponent equilibria and diffusivities from pure component data. Experimental measurements and computer simulations are essential to develop reliable prediction models. The binary systems chosen will be several mixtures of n-alkanes whose pure component adsorption equilibria and diffusion in silicalite have been well-characterized. Binary diffusivities will be measured for three different modes: 1) co-diffusion, 2) counter-diffusion, and 3) a novel chromatographic mode which is only possible with a membrane configuration. In a separate set of experiments, binary equilibria of chosen systems will be measured to enable accurate interpretation of diffusion data. Molecular simulations will be performed to extend the available simulation techniques to a novel steady-state non-equilibrium method. This approach will complement the experimental measurements more closely than has been previously possible and simultaneously lead to a more efficient method of deriving accurate statistics. The findings will fill substantial voids in the present understanding of thermodynamics and transport in micropores by combining molecular simulations and novel experiments to resolve a number of fundamental controversies that have plagued progress in the study of zeolites. ***