Design of Hybrid Materials for Gas Separations Using Molecular Simulation

摘要提案编号：CTS-9984621主要研究者：大卫M.学校：Texas A& M UniversityTitle：利用分子模拟设计用于气体分离的杂化材料由于经济和环境的驱动力，一类新兴的气体分离，其中必须从轻气流中去除较高分子量的稀物质，变得越来越重要。实例包括从空气中去除挥发性有机化合物和从天然气中去除较高分子量烷烃。 本项目研究了一种新的混合膜，用于这种分离。 该膜是介孔（5纳米）陶瓷的表面衍生的有机低聚物具有所需的化学功能。 这些膜的一个非常有用的方面是，自由体积和表面化学可以独立地修改;前者的量与沉积了多少低聚物链有关，而后者由所选低聚物的化学决定。 这两个量都可以变化，以获得特定分离的最佳特性。 除了实验合成和测试，分子模拟被用作推进这些杂化膜工程的主要工具，并为材料设计提供了一种手段。膜过程通常为传统的气体分离过程提供有利的经济替代方案。 工艺经济学要求用于这种分离的膜必须对较大的、更稀的组分具有选择性;这种类型的选择性与大多数膜分离中利用的通常的“筛分”行为相反。这项工作探讨了一种新型膜的合成和评价，这种膜是通过用有机链对多孔陶瓷材料的表面进行化学改性而形成的。 这种处理创造了一个对较大有机化合物友好的环境，并增强了它们从气流中的去除。这种分离策略预计在实践中会产生经济和操作优势。

ABSTRACTProposal Number: CTS-9984621Principal Investigator: David M. FordInstitution: Texas A&M UniversityTitle: Design of Hybrid Materials for Gas Separations Using Molecular SimulationAn emerging class of gas separations, where a dilute species of higher molecular weight must be removed from a light gas stream, is becoming increasingly important due to economic and environmental driving forces. Examples include the removal of volatile organic compounds from air and the removal of higher molecular weight alkanes from natural gas. This project examines a novel hybrid membrane for such separations. The membranes are mesoporous (5 nanometer) ceramics that are surface-derivatized with organic oligomers having desired chemical functionalities. A very useful aspect of these membranes is that free volume and surface chemistry can be modified independently; the former quantity is related to how many oligomer chains are deposited, while the latter is dictated by the chemistry of the chosen oligomer. Both quantities can be varied to obtain optimal characteristics for a particular separation. In addition to experimental synthesis and testing, molecular simulation is being used as a primary tool for advancing the engineering of these hybrid membranes and providing a means for materials design. Membrane processes often provide favorable economic alternatives to traditional gas-separation processes. Process economics dictate that membranes for such separations must be selective for the larger, more dilute components; this type of selectivity is the opposite of the usual "sieving" behavior exploited in most membrane separations. This work explores the synthesis and evaluation of a novel type of membrane created by chemically modifying the surfaces of porous ceramic materials with organic chains. Such treatment creates an environment that is friendly to larger organic compounds and enhances their removal from the gas stream. Such a separation strategy is expected to yield economic and operational advantages in practice.