Surfactant-Assisted on-Acid Interfacial Polymerization of Porous Polymer Membranes for Organic Solvent Nanofiltration

用于制造燃料和化学品的工业过程通常包括许多能源密集型分离步骤，以从输出流中回收有价值的产品。目前估计，进行这些工业分离所需的能源占国内总能源消耗的10%至15%。用基于膜的过滤过程取代传统的分离技术，如蒸馏，将减少工业能源需求，提高燃料和化学净化过程的可持续性。然而，相对较少的膜可以承受暴露于苛刻的有机溶液和高操作温度。现有的制备聚合物膜材料的方法在生产有机溶剂纳滤（OSN）应用所需的化学结构和材料性能方面的能力有限。该项目将探索一种新的策略来制造坚固的聚合物膜，可用于减少当今一些最重要和最具挑战性的工业过程中的碳足迹，包括分离苯、甲苯、乙苯和二甲苯的混合物（BTEX）和碳氢化合物分馏。该项目将提供机会，通过大学的“化学开放日”活动，与德克萨斯州大学城的社区成员分享膜过滤的科学概念。研究者还将为当地高中生组织为期四天的夏令营，在那里他们将学习膜材料的基本化学和物理。该项目的中心目标是开发一种在非水酸性界面上制造交联聚合物膜的新策略。这一目标将通过阐明表面活性剂辅助酸上界面聚合（SAAIP）反应的基本机制，以及解决在非水酸界面上制造高质量膜的技术挑战来实现。该研究计划的动机是假设在酸界面上自组装的表面活性剂可以通过静电相互作用提高界面附近的局部单体浓度，从而促进界面聚合。这一假设将通过三个研究目标进行验证：(1)通过酸度、表面张力、自组装和静电相互作用等关键因素阐明SAAIP以静电相互作用为中心的机制；(2)调整动力学并自主优化SAAIP的反应条件，以获得具有纳滤应用所需性能的无缺陷超薄膜；(3)展示了saaip在BTEX分离和石油分馏中的非常规纳滤性能。成功开发这种酸界面聚合策略将扩大界面膜合成的可用化学空间，超越目前最先进的水界面反应。因此，具有新功能，增强稳定性和OSN所需的精确分子选择性的膜材料将成为可能。该项目由化学、生物工程、环境和运输系统部门的界面工程项目和材料研究部门的聚合物项目提供支持。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The industrial processes used to manufacture fuels and chemicals often include many energy-intensive separation steps to recover valuable products from the output streams. Current estimates of the energy required to perform these industrial separations range from 10 to 15% of total domestic energy consumption. Replacing conventional separation technologies like distillation with membrane-based filtration processes will reduce industrial energy demand and improve the sustainability of fuel and chemical purification processes. However, relatively few membranes can withstand exposure to harsh organic solutions and high operating temperatures. Existing methods for fabricating polymeric membrane materials have limited ability to produce the types of chemical structures and materials properties needed for organic solvent nanofiltration (OSN) applications. This project will explore a novel strategy to fabricate robust polymer membranes that can be used to reduce the carbon footprint of some of today’s most important and challenging industrial processes, including separating mixtures of benzene, toluene, ethylbenzene, and xylenes (BTEX) and hydrocarbon fractionations. The project will provide opportunities to share the scientific concepts of membrane filtration with members of the College Station, TX, community through the university’s “Chemistry Open House” event. The investigator will also organize a four-day summer camp for regional high school students, where they will learn about the fundamental chemistry and physics of membrane materials. The central project goal is to develop a new strategy to fabricate crosslinked polymer membranes on nonaqueous acid interfaces. This goal will be achieved by elucidating the fundamental mechanism of the surfactant-assisted on-acid interfacial polymerization (SAAIP) reaction, and by addressing the technical challenges associated with fabricating high-quality membranes on nonaqueous acid interfaces. The research plan is motivated by the hypothesis that self-assembled surfactants on an acid interface can promote interfacial polymerization by enhancing local monomer concentration near the interface via electrostatic interactions. This hypothesis will be tested over three research objectives: (1) elucidating the electrostatic interaction-centered mechanism of SAAIP by varying key factors such as acidity, surface tension, self-assembly, and electrostatic interaction; (2) tailoring the kinetics and autonomously optimizing the reaction conditions for SAAIP to access defect-free, ultrathin membranes possessing the desired properties for nanofiltration applications; and (3) demonstrating the SAAIP-enabled unconventional nanofiltration performance for BTEX separation and petroleum fractionation. Successfully developing this on-acid interfacial polymerization strategy will expand the available chemical space for interfacial membrane synthesis beyond the current state-of-the-art aqueous interfacial reactions. As a result, membrane materials with new functionalities, enhanced stability, and the precise molecular selectivity required for OSN will be made possible. This project is supported by the Division of Chemical, Bioengineering, Environmental, and Transport Systems’s Interfacial Engineering program and the Division of Materials Research’s Polymers program.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.