STTR Phase I: COF-based Membrane for Refrigeration

这项小型企业技术转让（STTR）第一阶段项目的广泛影响将来自于纳米多孔膜过滤技术的成功开发，该技术可以实现气相和液相的低能耗、低成本和快速分子分离。提出的技术是开发用于分离液体或气体样品到其组分的膜的新材料。虽然目前项目的主要重点是一种新型制冷系统，但其核心技术具有广泛的潜在应用，包括农业和饮用水源的海水淡化、血液透析、工业液-液分离、空气中的二氧化碳去除和空气中的氧气分离。这个STTR一期项目的智力优势是推进了一种基于共价有机框架（COF）的二维（2D）分子筛，以实现一种使用水和吸热盐的新型制冷系统。闭式循环制冷系统需要纳米多孔膜将使用过的冷却剂再生成两种流（水和盐水），以便随后的重新组合再次提供冷却效果。在低压下高通量和高截留水合NH4阳离子是操作成功的关键。该项目将探索二胺与二碳腈在COF中的缩合反应，研究NH基的氢取代如何优化对NH4(H2O)4离子的排斥，并研究电荷在二维COF中的排斥机制。基准包括在2 L/m2/hr的通量下至少60%的NH4(H2O)4离子截留和最终COF的经济有效合成。该项目的具体目标是：1)使用COF前形成路径探索至少11种变化，2)使用COF后形成路径创建至少4种孔隙变化，3)使用COF/AAO膜生成并分析渗透和保留样品。由此产生的纳米多孔COF及其相关的合理设计过程不仅将使所提出的制冷应用成为可能，而且将为未来膜的应用提供指导。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 broader impact of this Small Business Technology Transfer (STTR) Phase I project would come from the successful development of a nano-porous membrane-based filtration technology enabling lower-energy, low-cost, and rapid molecular separations in gas and liquid phases. The proposed technology is to develop new materials for membranes used to separate liquid or gas samples into their components. Although the primary focus of the current project is a new type of refrigeration system, the core technology has a wide range of potential applications including desalination of agricultural and potable water sources, blood dialysis, industrial liquid-liquid separations, CO2 removal from air, and separation of oxygen from air. The intellectual merit of this STTR Phase I projct is to advance a 2-dimensional (2D) molecular sieve, based on a Covalent Organic Framework (COF), to enable a new type of refrigeration system using water and endothermic salts. The closed-cycle refrigeration system requires a nano-porous membrane to regenerate the used coolant into two streams (water and brine) so that a subsequent recombination will again provide a cooling effect. High flux and high rejection of hydrated NH4 cations at low pressures are critical to successful operation. The project will explore the condensation of diamines with dicarbonitriles in COF formation, study how hydrogen substitution in NH groups can optimize rejection of NH4(H2O)4 ions, and investigate how charge works as a rejection mechanism in 2D COFs. Benchmarks include at least 60% rejection of NH4(H2O)4 ions at a flux of 2 L/m2/hr and a cost-effective synthesis of the final COF. The specific goals of the project are to: 1) explore at least 11 variations using a pre-COF formation route, 2) create at least 4 pore variations using a post-COF formation route, and 3) produce and analyze permeate and retentate samples using COF/AAO membranes. The resulting nanoporous COF and its associated rational design process will not only enable the proposed refrigeration application, but will also serve as a guide for future membrane applications.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.