Collaborative Research: Selective Flow through Membrane Pores with in situ Change of Wettability

合作研究：通过膜孔的选择性流动与润湿性的原位变化

• 批准号: 2012632
• 负责人: Seokjhin Kim
• 金额: $ 21.75万
• 依托单位: Oklahoma State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2012632&HistoricalAwards=false
• 关键词: Collaborative; Research; Selective; Flow; through

The goal of this project is to separate oil and water using special membranes (filters with very small pores/passages) that change how each fluid behaves at the membrane surface by applying an electric potential. The efficiency of the oil-water separation depends on the interaction of each of these components with the membrane. For example, a hydrophilic, or water-loving, membrane lets water through but rejects oil. However, the oil eventually plugs the pores, preventing additional water from moving through the membrane. This problem could be resolved if the membrane could be temporarily switched to be oleophilic, or oil-loving, to let the oil through. This switchable functionality would be especially helpful when the oil phase is valuable, such as in crude oil production where oil-water mixtures are abundant, or in the dairy industry where both the oil and water phases are valuable. Unfortunately, the ability to change membrane properties during operation is very difficult to achieve. This project will accomplish this goal by changing the surface properties of the membranes with molecules that change their orientation with electricity. First, molecules that respond to electricity and result in the desired change in hydrophilicity or oleophilicity will be identified. As an intermediate goal for this project, a membrane capable of controlling the flow of water will be developed by coating water-controlling molecules onto the membrane surface. The same will be done for oil by coating with oil-controlling molecules. Eventually, by coating both oil- and water-controlling molecules, the flow of oil and water will be controlled to separate oil-water mixtures on demand. The switchable membranes will be of societal benefit through their application in wastewater treatment, energy-efficient fuel production, dairy processes, and many others. In addition, the project will directly involve undergraduate and graduate students in impactful, transformative research. The investigators and students will, in turn, participate in rural STEM K-12 outreach programs working to develop the next generation of scientists and engineers capable of solving the problems of tomorrow. Membranes are a preferred technology for efficient oil-water separation given factors such as energy efficiency, relatively low material costs, and their demulsifying function. Membranes appear in a variety of forms constructed from different polymers or inorganic materials with added moieties that control hydrophilicity and/or oleophilicity of the membrane surfaces. However, once the surface properties of membranes are set to permeate water, they cannot be changed to permeate the oil that eventually clogs the pores. Devising a way to switch membrane functionality to and from oil- or water-permeating will mitigate fouling issues and enable collection of the oil phase. Such membrane technology would benefit many industrial applications, including enhanced oil recovery with low-salinity water flooding or the dairy industry where the oil phase is valuable. Therefore, the investigators propose a new way to selectively control water and oil flow through the membrane in situ; wettability of oil and water will be controlled through interactions with adsorbed surface molecules that change conformation with applied electric potentials. Wettability is one of the factors that control liquid flow through pores, along with the geometry and hydraulic head. Membranes that can selectively permeate only one phase at a time from oil-water mixtures will be achieved as follows: (1) First, the surface molecules that produce large changes in the contact angle of water and oil with electricity (“controlling molecules”) will be identified. The optimal hydraulic pressure and geometry with the given changes will be calculated and fabricated. (2) Next, one membrane with the optimal geometry coated with the water-controlling molecules will be prepared. The same will be prepared for oils. The separation performance of the membranes as well as the durability of surface molecules will be characterized. (3) The final project objective is to develop a membrane with "control valves" coated with two controlling molecules that modulate the wettability of oil and water simultaneously. This hybridized surface will be characterized, and membrane performance and durability will be assessed. The success of this project will enable a new approach to liquid-liquid separation and enhance the educational experiences of the undergraduate and graduate students conducting the research.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.

该项目的目标是使用特殊的膜（带有非常小的孔/通道的过滤器）通过施加电势来改变每种流体在膜表面的行为，从而分离油和水。油水分离的效率取决于这些成分与膜的相互作用。例如，亲水或亲水的膜允许水通过，但拒绝油。然而，油最终会堵塞毛孔，阻止额外的水通过膜。这个问题可以解决，如果膜可以暂时切换为亲油，或亲油，让油通过。这种可切换的功能在油相有价值的情况下尤其有用，例如在油水混合物丰富的原油生产中，或者在油和水相都有价值的乳制品行业。不幸的是，在操作过程中改变膜性质的能力是很难实现的。这个项目将通过用分子改变膜的表面特性来实现这一目标，这些分子可以用电改变膜的取向。首先，对电作出反应并导致亲水性或亲油性期望变化的分子将被确定。作为该项目的中间目标，将通过在膜表面涂覆控水分子来开发一种能够控制水流动的膜。在油上涂上控制油的分子也是同样的方法。最终，通过涂覆控制油和水的分子，油和水的流动将被控制，以根据需要分离油水混合物。可切换膜将通过其在废水处理、节能燃料生产、乳制品加工和许多其他方面的应用而具有社会效益。此外，该项目将直接涉及本科生和研究生在有影响力的，变革性的研究。反过来，研究人员和学生将参加农村STEM K-12外展项目，致力于培养有能力解决未来问题的下一代科学家和工程师。考虑到能源效率、相对较低的材料成本和破乳功能等因素，膜是高效油水分离的首选技术。膜以各种形式出现，由不同的聚合物或无机材料构成，并添加了控制膜表面亲水性和/或亲油性的部分。然而，一旦膜的表面特性被设定为渗透水，它们就不能被改变以渗透最终堵塞毛孔的油。设计一种将膜功能切换为油渗透或水渗透的方法，将减轻污染问题，并使油相的收集成为可能。这种膜技术将有利于许多工业应用，包括通过低矿化度水驱提高石油采收率，或油相有价值的乳制品行业。因此，研究人员提出了一种新的方法来选择性地控制水和油通过膜的流动；油和水的润湿性将通过与被吸附的表面分子的相互作用来控制，这些分子会随着施加的电位而改变构象。润湿性是控制液体流过孔隙的因素之一，还有几何形状和水头。一次只能选择性地从油水混合物中渗透一个相的膜将通过以下方式实现：(1)首先，将确定使水和油与电的接触角发生大变化的表面分子（“控制分子”）。在给定的变化条件下，计算并制造出最优的液压压力和几何形状。(2)下一步，将制备一种具有最佳几何形状的膜，并涂覆控水分子。油也是如此。膜的分离性能以及表面分子的耐久性将被表征。(3)最终的项目目标是开发一种带有“控制阀”的膜，上面涂有两个控制分子，可以同时调节油和水的润湿性。这种杂交表面将被表征，膜的性能和耐久性将被评估。该项目的成功将为液液分离提供一种新的方法，并提高进行该研究的本科生和研究生的教育经验。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。