EAGER: LbL Polymer Thin Films for Reaction-Assisted Acid Gas Removal

EAGER：用于反应辅助酸性气体去除的 LbL 聚合物薄膜

• 批准号: 1202447
• 负责人: Benjamin Wilhite
• 金额: $ 10万
• 依托单位: Texas A&M Engineering Experiment Station
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-03-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1202447&HistoricalAwards=false
• 关键词: EAGER; LbL; Polymer; Thin; Films

1202447-WilhiteSingle composite membrane for reaction-assisted separations. Hydrogen, which can be produced via catalytic reforming of virtually any hydrocarbon resource, has emerged as a promising global energy currency. However, no elegant solution for mitigating the undesired by-products of hydrogen production (e.g., CO, CO2) currently exists- thus, presenting a grand challenge. We propose to simultaneously purify H2, destroy CO and isolate CO2 using a single composite membrane comprised of a layer-by-layer (LbL) assembled polymeric thin film for selective removal of CO2 and an inorganic catalytic membrane for converting CO to CO2 via water-gas-shift reaction. The resulting composite catalytic-permselective membranes represent a unique and transformative approach to hydrogen purification by integrating layer-by-layer assembly techniques for constructing permselective polymer films with washcoating methods to construct catalytic films to achieve reaction-assisted gas separations in a single composite membrane. Proton-exchange membrane fuel cells (PEMFCs), which use hydrogen as a fuel, are a leading candidate for next-generation power systems, owing to their durability, portability and/or scalability. However, by-products from hydrogen production such as CO can poison the PEMFC and dramatically limit lifetime and performance; CO2, another by-product, dilutes the hydrogen stream and must be removed prior to endpoint usage. Current strategies for reducing CO-levels involve coupling of the equilibrium-limited water-gas-shift catalysts (WGS) with palladium-based hydrogen-permselective membranes. Because of palladium's cost and low hydrogen permeability, replacing palladium with alternative materials is viewed as a grand challenge in realizing cost-effective high-purity hydrogen. In the proposed work the LbL membranes may compete with or even surpass palladium. Recent work in reverseselective polymeric membranes indicates that select polymers (i.e., poly(ethylene oxide) (PEO) and poly(allylamine) (PAH)) are very cost-effective at separating CO2 from H2. The proposed LbL thin films containing PAH, coupled with WGS catalyst to destroy CO, may potentially produce high-purity, high-pressure hydrogen from hydrogen reformate streams containing undesired by-products at low cost. This exploratory grant will explore the use of LbL membranes for permselective gas separation, their compatibility with reforming chemistries and with catalytic thin-film deposition techniques, with the ultimate goal of demonstrating a prototype composite catalytic-permselective membrane capable of permselective CO2 removal from reformate mixtures at typical (100 - 180C) reaction temperatures. The proposed research is high-risk, as all three central hypotheses are untested to-date. Gas transfer in LbL assemblies is relatively unexplored, partly because there is little crossover in the fields of LbL assembly and gas separations. The compatibility of LbL deposition techniques with catalytic washcoating methods has not been explored in the literature to-date. Lastly, the durability and performance of LbL thin films have not been investigated under reaction environments or at elevated temperatures. Scientific results regarding each of these hypotheses are of substantial intellectual value to the separations community. Validation of the proposed coupling of catalytic and LbL polymeric films in a composite catalytic-permselective membrane will enable the rigorous development of an innovative approach to realizing low-cost, highly selective gas separation membranes. For the specific case of a water-gas-shift catalytic layer enhancing the permselectivity of a CO2-selective LbL film, recent theoretical predictions by Wilhite indicate that H2-CO permselectivities in excess of 250:1 (comparable to Pd films) may be achieved at roughly 1/100th the cost. By itself, this achievement could transform the field of hydrogen purification membranes. Planned outreach activities include mentoring of undergraduate researchers through the Department of Chemical Engineering's REU program and Engineering Scholars program. The PIs will also host an international research internship through the International Scholars Program at TAMU. Summer research opportunities will also be available to K-12 teachers through the College of Engineering's RET program.

1202447-Wilhite用于反应辅助分离的单复合膜。氢气可以通过几乎任何碳氢化合物资源的催化重整来生产，已成为一种有前途的全球能源货币。 然而，目前尚不存在缓解氢气生产中不需要的副产品（例如CO、CO2）的优雅解决方案，因此，这是一个巨大的挑战。我们建议使用单一复合膜同时纯化 H2、破坏 CO 和分离 CO2，该复合膜由用于选择性去除 CO2 的逐层 (LbL) 组装聚合物薄膜和用于通过水将 CO 转化为 CO2 的无机催化膜组成。气体变换反应。由此产生的复合催化选择性渗透膜代表了一种独特的、革命性的氢气纯化方法，通过集成逐层组装技术构建选择性渗透聚合物薄膜，并通过洗涂方法构建催化薄膜，从而在单个复合膜中实现反应辅助气体分离。使用氢作为燃料的质子交换膜燃料电池（PEMFC）因其耐用性、便携性和/或可扩展性而成为下一代电力系统的主要候选者。然而，制氢过程中产生的副产品（例如 CO）可能会毒害 PEMFC，并极大地限制其使用寿命和性能；另一种副产品二氧化碳会稀释氢气流，必须在端点使用前去除。目前降低二氧化碳含量的策略包括将平衡限制水煤气变换催化剂 (WGS) 与钯基氢选择性渗透膜相结合。由于钯的成本和氢渗透性低，用替代材料替代钯被视为实现具有成本效益的高纯度氢的巨大挑战。在拟议的工作中，LbL 膜可能会与钯膜竞争甚至超越。反向选择性聚合物膜的最新研究表明，精选聚合物（即聚环氧乙烷 (PEO) 和聚（烯丙胺）(PAH)）在分离 CO2 和 H2 方面非常经济高效。所提出的含有 PAH 的 LbL 薄膜，与 WGS 催化剂相结合以破坏 CO，有可能以低成本从含有不需要的副产物的氢重整物流中生产高纯度、高压氢气。该探索性资助将探索 LbL 膜在选择性渗透气体分离中的用途、其与重整化学和催化薄膜沉积技术的兼容性，最终目标是展示能够从重整混合物中选择性渗透二氧化碳的原型复合催化选择性渗透膜在典型的（100 - 180°C）反应温度下。拟议的研究具有高风险，因为迄今为止所有三个中心假设都未经检验。 LbL 组件中的气体传输相对尚未被探索，部分原因是 LbL 组件和气体分离领域几乎没有交叉。迄今为止，文献中尚未探讨 LbL 沉积技术与催化修补基面涂层方法的兼容性。最后，LbL 薄膜的耐久性和性能尚未在反应环境或高温下进行研究。关于这些假设的科学结果对于分离界来说都具有重大的知识价值。对复合催化选择性渗透膜中催化和 LbL 聚合物膜耦合的验证将有助于严格开发创新方法，以实现低成本、高选择性气体分离膜。对于水煤气变换催化层增强 CO2 选择性 LbL 薄膜选择性渗透性的具体情况，Wilhite 最近的理论预测表明，可以实现超过 250:1（与 Pd 薄膜相比）的 H2-CO 选择性渗透性成本约为其 1/100。就其本身而言，这一成就可能会改变氢纯化膜领域。计划的外展活动包括通过化学工程系的 REU 计划和工程学者计划对本科生研究人员进行指导。 PI 还将通过 TAMU 的国际学者计划举办国际研究实习。通过工程学院的 RET 项目，K-12 教师还将获得暑期研究机会。