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-用于反应辅助分离的单一复合膜。氢气可以通过催化重整几乎任何碳氢化合物资源来生产，已经成为一种有前途的全球能源货币。 然而，没有用于减少氢气生产的不期望的副产物（例如，CO，CO2）目前存在-因此，提出了巨大的挑战。我们建议同时净化H2，破坏CO和隔离CO2使用一个单一的复合膜由一个层由层（LbL）组装的聚合物薄膜选择性去除CO2和无机催化膜通过水煤气变换反应将CO转化为CO2。所得到的复合催化-选择性渗透膜代表了一种独特的和变革性的氢气纯化方法，该方法通过将用于构建选择性渗透聚合物膜的逐层组装技术与洗涂方法相结合来构建催化膜，以在单个复合膜中实现反应辅助的气体分离。质子交换膜燃料电池（PEMFC）使用氢作为燃料，由于其耐用性，便携性和/或可扩展性，是下一代电力系统的主要候选者。然而，来自氢气生产的副产物（如CO）会使PEMFC中毒，并极大地限制寿命和性能;另一种副产物CO2会稀释氢气流，必须在终点使用之前去除。目前降低CO水平的策略涉及平衡限制的水煤气变换催化剂（WGS）与钯基氢选择性渗透膜的偶联。由于钯的成本和低的氢渗透性，用替代材料代替钯被视为实现具有成本效益的高纯氢的巨大挑战。在所提出的工作中，LbL膜可以与钯竞争甚至超过钯。最近在反向选择性聚合物膜中的工作表明，选择聚合物（即，聚（环氧乙烷）（PEO）和聚（烯丙基胺）（PAH））在从H2中分离CO2方面是非常成本有效的。所提出的含有PAH的LbL薄膜，与WGS催化剂结合以破坏CO，可以潜在地以低成本从含有不期望的副产物的氢重整产物流生产高纯度、高压氢。这项探索性资助将探索LbL膜用于选择性渗透气体分离的用途，其与重整化学和催化薄膜沉积技术的兼容性，最终目标是展示一种原型复合催化选择性渗透膜，该膜能够在典型的（100 - 180 ℃）反应温度下从重整混合物中选择性渗透CO2。拟议的研究是高风险的，因为所有三个中心假设都未经测试。LbL组件中的气体传输相对未被探索，部分原因是在LbL组件和气体分离领域中几乎没有交叉。LbL沉积技术与催化修补基面涂覆方法的相容性迄今尚未在文献中探索。最后，LbL薄膜的耐久性和性能尚未在反应环境下或在高温下进行研究。关于这些假设中的每一个的科学结果对分离社区都具有实质性的知识价值。在复合催化选择性渗透膜中催化和LbL聚合物膜的拟议耦合的验证将使得能够严格开发实现低成本、高选择性气体分离膜的创新方法。对于水煤气变换催化层增强CO2选择性LbL膜的选择渗透性的特定情况，Wilhite最近的理论预测表明，可以以大约1/100的成本实现超过250：1的H2-CO选择渗透性（与Pd膜相当）。这一成就本身就可以改变氢气纯化膜领域。计划的推广活动包括通过化学工程系的REU计划和工程学者计划指导本科研究人员。PI还将通过TAMU的国际学者计划举办国际研究实习。暑期研究机会也将通过工程学院的RET计划提供给K-12教师。