2020 — 2023 |
Seo, Dongjin |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Collaborative Research: Selective Flow Through Membrane Pores With in Situ Change of Wettability @ Brigham Young University
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.
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