Collaborative Research: Enabling rational design of MOF-polymer mixed matrix membranes for liquid separations through understanding of microscale and macroscale properties

汽油、塑料、洗衣液、许多药品和化妆品都是从有机液体中提取的。有机液体本质上是原油的液体部分。原油中的分子是一种复杂的混合物，必须先将其分离，然后才能转化为有用的消费品。今天，分离混合物需要将有机液体煮沸和蒸馏。煮沸液体需要大量的能量输入，其成本最终转嫁给消费者。考虑到从有机液体中提取的大量消费产品，这种分离利用了相当大的一部分（约10%）的国家总能源消耗。有机液体的替代、低成本和低能耗分离的发展将使国家在减少能源消耗的同时继续或提高其生活水平。为了实现这一目标，人们对使用固体质量分离剂来分离有机液体而不是蒸馏混合物越来越感兴趣。质量分离剂的一个这样的例子是膜，它作为一个筛子来分离混合物的成分。与宏观筛子不同，膜包含具有特定化学功能的纳米级孔隙。分子通过孔隙，以不同的方式与化学功能相互作用，导致不同类型分子的分离。为了分离可以溶解许多物质的有机液体，膜必须具有化学坚固性。本研究项目将结合传统和先进的表征技术来跟踪有机分子通过膜的运动，以促进分离有机液体的质量分离剂的合理设计。该研究项目将试图了解有机液体在聚合物、金属-有机框架（mof）和由这两种成分组成的混合基质膜中的传输、结构和吸附特性的变化。扩散将使用传统的分子通量输运测量以及脉冲场梯度核磁共振波谱来确定。为了评估亚微米空间分辨率的扩散，将使用高磁场梯度和高静态磁场。将建立一个分析模型，将微观和宏观的扩散系数、输运性质、吸附和结构性质联系起来。该模型的目标是开发用于有机液体分离的基于mof的混合基质膜的设计原则。这项工作的教育和推广方面将利用现有的项目，引入动画和教育演示，并让学生参与与膜分离相关的定义明确的工程项目。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。

Gasoline, plastics, laundry detergent, many pharmaceuticals, and cosmetics are all derived from organic liquids. Organic liquids are essentially the liquid fraction of crude oil. The molecules in crude oil are a complex mixture, that must first be separated before they can be converted to useful consumer products. Today, separation of the mixture requires the organic liquids be boiled and distilled. Boiling the liquid requires a large energy input, the cost of which is ultimately passed on to the consumer. Given the vast consumption of consumer products derived from organic liquids, this separation utilizes a sizable fraction (about 10%) of the nation's total energy consumption. The development of alternative, low-cost and low-energy separations of organic liquids will allow the nation to continue, or improve upon, its standard of living while reducing energy consumption. To achieve this goal, there is growing interest in using solid mass separating agents to separate organic liquids, rather than distilling the mixture. One such example of a mass separating agent is a membrane, which acts as a sieve to separate the components of the mixture. Unlike a macroscopic sieve, a membrane contains nanometer-sized pores with specific chemical functionalities. Molecules pass through the pores and interact with the chemical functionalities in different manners, leading to a separation of different types of molecules. To separate organic liquids, which can dissolve many materials, the membrane must be chemically robust. This research project will couple traditional and advanced characterization techniques to track the movement of the organic molecules through membranes, in order to advance the rational design of mass separating agents that separate organic liquids. This research project will seek to understand changes of the transport, structural, and sorption properties of organic liquids in polymers, metal-organic frameworks (MOFs), and mixed-matrix membranes consisting of both of these components. Diffusion will be determined using both traditional transport measurements of molecular flux, as well as pulsed field gradient nuclear magnetic resonance spectroscopy. To evaluate diffusion with sub-micrometer spatial resolution, high magnetic field gradients and a high static magnetic field will be used. An analytical model will be developed to link microscopic and macroscopic diffusivities, transport properties, sorption, and structural properties. The goal of this model will be to develop design principles for MOF-based mixed-matrix membranes for organic liquid separations. Educational and outreach aspects of the work will leverage existing programs, introduce animations and educational demonstrations, and offer students participation in well-defined engineering projects related to membrane separations.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.