Morphology-Controlled Carbon Molecular Sieve Membranes for Gas Separation

能源行业，包括石油和天然气设施、石化生产和发电，产生废气流。这些气流是高温、高压的，可能含有有毒化学物质。在气体能够安全地释放到大气中之前，必须有选择地将化学上相似的小分子从气流中移除，以满足政府的监管标准。传统的气体分离技术，如低温蒸馏和吸收，是能源密集型的，因此增加了操作成本和进一步的环境负担。基于膜的分离是一种具有竞争力的替代气体分离技术，但那些用于工业气体服务的技术将受益于能够在更高温度下使用的性能改进。该项目将建立一种受控的膜制造工艺，以克服在气体分离中工业使用膜所面临的主要限制，包括控制内部孔网络和材料老化的能力。该制备方法将聚合物前驱体和多孔液体结合在一起，形成对目标分子具有高选择性(偏好)和良好机械性能的“混合基质”膜。所加入的材料显着提高了膜在更高温度下工作的能力，使其与能量密集型分离方法相比更具竞争力。该项目的成果预计将广泛适用于许多类型的气体分离过程，并可能刺激空气污染控制新技术的发展。通过研究项目为本科生和研究生提供教育机会。首席调查员还将利用密苏里科技大学现有的项目，与K-12教育工作者和高中生接触，开展提高公众科学素养的活动。本项目将系统地研究最近开发的氟化共聚酰亚胺(FCP)平台的结构/性能关系，该平台具有优异的气体分离性能。本研究的目的是为了更好地了解聚合物前驱体的微观结构与所合成的碳分子筛膜的物理老化和气体分离性能之间的基本关系。这种FCP材料和相关混合物具有很高的热稳定性和化学稳定性，使其适合在高温或恶劣的化学环境中进行分离，如天然气加工或烯烃/烷烃分离。在这个项目中，研究人员将通过共价键将聚合物前驱体的主干结构与多孔有机笼子(POC)纳米颗粒结合在一起，合成一系列FCP及相关材料。我们将探索主链结构的修饰和聚合物前驱体掺杂POCs对膜的形态、自由体积、过渡层、物理老化和气体分离性能的影响，其目的是建立这些新型膜的基本结构/性能/性能关系。将描述纯气体的气体溶解度、扩散率和渗透率随温度和压力的变化情况。类似地，将评估生成的FCP和衍生的基于POC的CMS膜上的混合气体渗透性能，以应用于天然气或烯烃/烷烃分离。该项目将提供本科和研究生教育机会，并与密苏里科技大学现有的项目相结合，研究人员将为K-12教育工作者和高中外展活动创建课堂模块。产品将通过YouTube和调查者研究网站向公众分发。该奖项反映了NSF的法定使命，并已通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Energy industries, including oil and gas facilities, petrochemical production, and electric power generation, produce exhaust gas streams. These gas streams are hot, high-pressure, and can contain noxious chemicals. Before the gas can be safely released to the atmosphere, small, chemically similar molecules must be selectively removed from the stream to meet government regulatory standards. Conventional gas separation technologies such as cryogenic distillation and absorption are energy-intensive and, thus, add to operational cost and further burden the environment. Membrane-based separations are a competitive alternative gas separation technology, but those used in industrial gas service stand to benefit from performance improvements that enable use at higher temperatures. This project will establish a controlled membrane fabrication process that overcomes the primary limitations facing industrial use of membranes in gas separations, including the ability to control the internal network of pores and how the material ages. The fabrication process incorporates polymer precursors and porous liquids to form a "mixed matrix" membrane with high selectivity (preference) for a target molecule and good mechanical properties. The incorporated materials significantly increase the ability of the membranes to operate at higher temperatures making them more competitive with the energy-intensive separation methods. The results of this project are expected to be broadly applicable to many types of gas separation processes and may spur the development of new technologies for air pollution control. Educational opportunities will be provided to undergraduate students and graduate students through research projects. The principal investigator will also leverage existing programs at Missouri University of Science and Technology to engage with K-12 educators and high school students in activities that enhance public science literacy. This project will systematically investigate structure/property relationships in a recently developed platform of fluorinated copolyimides (FCPs), which exhibit outstanding gas separation performance. The objective of this study is to develop a better understanding of the fundamental relationships between the microstructure of the polymer precursor and physical aging and gas separation performance of the resultant carbon molecular sieve (CMS) membrane. Such FCP materials and related blends have high thermal and chemical stability, making them suitable candidates for separations at high temperatures or in harsh chemical environments, such as natural gas processing or olefin/paraffin separation. In this project, the investigator will synthesize a family of FCPs and related materials integrating the polymer precursor’s backbone structure with porous organic cage (POC) nanoparticles via covalent bonding. The effects of backbone structure modification and polymer precursor doping with POCs on morphology, free volume, transition layer, physical aging, and gas separation properties will be explored; the objective of which is to develop fundamental structure/property/performance relationships for these novel membranes. Gas solubility, diffusivity, and permeability as a function of temperature and pressure for pure gases will be characterized. Similarly, mixed gas permeation properties over the resulting FCP and derived POC-based CMS membranes will be assessed for application in natural gas or olefin/paraffin separations. The project will offer undergraduate and graduate education opportunities, and in conjunction with existing programs at Missouri University of Science and Technology, the investigator will create classroom modules for K-12 educators and high-school outreach events. Products will be distributed to the public through YouTube and investigator's research website.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.