Fundamental Studies of Novel SiC Nanoporous Materials for Separation Applications

点击翻译按钮获取中文摘要

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).0854427TsotsisThis NSF award by the Chemical and Biological Separations program supports work by Professors Theodore Tsotsis and Muhammad Sahimi at the University of Southern California to systematically investigate and further improve the technique of pre-ceramic polymer pyrolysis to produce nanoporous SiC membranes and films, which are both cost-efficient and industrially viable.In this project we propose the study of SiC membranes which show the potential to overcome some of the difficulties other membranes face, which have proven unstable in the presence of O2 and steam at temperatures higher than 300C; these are the conditions typically encountered in reactive separations for H2 production, and in fuel-cell applications. SiC is a promising material that has high fracture toughness, good thermal shock resistance, and is capable of withstanding high temperatures and corrosive environments. Our current research with these materials focuses on the preparation of appropriate SiC membrane supports, and the deposition on these substrates of thin nanoporous films by the pyrolysis of pre-ceramic polymeric precursors. Our preliminary studies have shown that using new types of PCS materials leads to the preparation of hydrogen-permselective membranes. However, significant progress must still be made before these SiC membranes become appropriate for practical applications. In this project we will, therefore, systematically investigate and further improve the technique of pre-ceramic polymer pyrolysis to produce nanoporous SiC membranes and films, which are both cost-efficient and industrially viable. Our 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. We 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, in that it will provide them with the opportunity 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. Our plan is to recruit qualified undergraduates as summer interns, and potentially as incoming graduate students. We plan to disseminate the results of our work through peer reviewed publications, presentations at technical meetings, and by makings all reports available on the Web. We will also take advantage of the ever evolving undergraduate curriculum program at USC, which emphasizes vertically- and horizontally-integrated degree projects consisting of emphasis-specific experimental/laboratory modules associated with each core Chemical Engineering course. The PI?s 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.