Novel SiC Nanoporous Materials for Separation Applications

用于分离应用的新型碳化硅纳米多孔材料

• 批准号: 0553349
• 负责人: Muhammad Sahimi
• 金额: $ 25万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0553349&HistoricalAwards=false
• 关键词: Novel; SiC; Nanoporous; Materials; Separation

Abstract: Nanoporous carbon molecular sieve membranes (CMSM) have been the focus of much previous research for separation of mixtures. Though CMSM exhibit improved properties over polymeric membranes, they are themselves unstable in the presence of O2 and steam at temperatures higher than 300 oC; these are the conditions typically encountered in reactive separations for H2 production, and in fuel-cell applications. Other inorganic membranes, like ceramic (e.g., alumina, silica, and zeolite) and metal (Pd, Ag, and their alloys) have, so far, also proven unstable, in these high-temperature applications, particularly in the presence of steam and CO. In this project we propose the study of SiC membranes that show the potential to overcome some of these difficulties. SiC is a promising material that has high fracture toughness, good thermal shock resistance, and is capable of withstanding high temperatures and corrosive environments. The preparation of SiC nanoporous membranes involves two key steps. First, the preparation of appropriate SiC supports, and second the deposition on these supports of crack- and pinhole-free, thin nanoporous SiC films. Previous research focused on the preparation of appropriate macro and mesoporous SiC membrane supports. In this project, the University of Southern California will deposit thin nanoporous films on these substrates by the pyrolysis of pre-ceramic polymeric precursors. As with the CMSM, the researchers emphasis will be on understanding the factors determining the ability of these SiC materials to separate gas mixtures, based on differences in molecular mobility and molecule-pore surface interactions. Research will proceed along two paths: (1) the preparation and characterization of SiC membranes, and the computational modeling of their molecular structure; and (2) the measurement and simultaneous computer simulation of sorption and transport of mixtures through these membranes. Coupling experiments and simulations will facilitate efforts to relate the membrane's molecular structure with its transport properties, and separation efficacy. This, in turn, will enable progress toward the long-term goal of first-principle molecular engineering and design of improved materials for adsorption and separation. This research project will provide a valuable educational experience and training for the graduate and undergraduate students involved, by training them to prepare and characterize a novel class of new materials, and to learn a host of state-of-the-art computational and experimental techniques. The urban setting of USC affords the opportunity to work with a variety of 2-4 year colleges in the area. The researchers will recruit qualified undergraduates as summer interns, and potentially as incoming graduate students. The experimental results will be disseminated through peer-reviewed publications, presentations at technical meetings, and by makings all reports available on the Web. The PIs envision integrating research findings and aspects of their work as the degree projects in the Reactor Analysis, Transport Phenomena, and Separation courses. The proposed novel SiC membranes show good potential for reactive applications for the production of hydrogen and for fuel-cell applications. In addition to focusing attention on an important class of materials, this project will also generate fundamental insight, which will impact the knowledge-base of the broader field of transport and reaction in nanoporous media, and is likely to catalyze new thinking and rapid new advances in the area.

摘要：纳米多孔碳分子筛膜（CMSM）一直是混合物分离的许多先前研究的重点。 尽管CMSM在聚合膜上表现出改善的性能，但它们本身在O2存在下不稳定，并且在高于300 OC的温度下蒸汽；这些是H2生产的反应性分离和燃料电池应用中通常遇到的条件。到目前为止，在这些高温应用中，尤其是在蒸汽和co中，在这个项目的存在下，我们建议其他无机膜，例如陶瓷（例如氧化铝，二氧化硅和沸石）和金属（PD，AG及其合金），在这些高温应用中也证明了不稳定的证明是不稳定的，尤其是在蒸汽和co中。在这个项目的存在下，我们建议我们在Sicmmmbranes的研究中表现出了一些困难，以克服某些困难。 SIC是一种有前途的材料，具有高断裂韧性，良好的热冲击性，并且能够承受高温和腐蚀性环境。 SIC纳米方膜的制备涉及两个关键步骤。首先，制备适当的SIC支持，其次是对这些裂纹和无针孔的薄纳米多孔SIC膜的支撑的沉积。先前的研究重点是制备适当的宏观和中孔SIC膜的支持。在这个项目中，南加州大学将通过陶瓷前聚合物前体的热解将薄纳米多孔膜放在这些底物上。与CMSM一样，根据分子迁移率和分子孔表面相互作用的差异，研究人员将重点在于理解这些SIC材料分离气体混合物的能力的因素。研究将沿着两条路径进行：（1）SIC膜的制备和表征，以及其分子结构的计算建模； （2）对混合物通过这些膜进行吸附和转运的测量和计算机模拟。耦合实验和模拟将有助于将膜的分子结构与其传输特性和分离功效联系起来。反过来，这将使朝着长期目标的前进目标朝着第一原理工程和改进的材料设计以吸附和分离的设计。该研究项目将为参与研究生和本科生提供宝贵的教育经验和培训，培训他们准备和描述新型新材料，并学习许多最先进的计算和实验技术。 USC的城市环境为该地区的各种2 - 4年的大学提供了机会。研究人员将招募有资格的大学生作为暑期实习生，并有可能为即将到来的研究生。实验结果将通过同行评审的出版物，技术会议上的演示以及网络上所有可用的报告来传播。 PIS设想将研究结果和工作的各个方面整合为反应堆分析，运输现象和分离课程中的学位项目。拟议的新型SIC膜显示出用于生产氢和燃料电池应用的反应性应用的良好潜力。除了将注意力集中在重要的材料上外，该项目还将产生基本的见解，这将影响纳米媒体中更广泛的运输和反应领域的知识基础，并可能会催化该地区的新思维和快速的新进步。