NSF-BSF: Impact of Electric- and Flow-Fields on Surfactant-Stabilized Emulsion Properties During Oil/Water Separation

从废水流中分离乳化油仍然是一个重大的工业挑战。膜过滤是少数几种可以去除乳化油滴的方法之一。然而，这些液滴的过滤由于严重的膜污染而变得复杂，其中通过膜的流体通道由于表面处的颗粒或溶液而减慢。开发一种节能的分离工艺，以最小的膜污染从水中去除乳化油，将使许多工业用户受益，包括石油和天然气生产商，食品加工商和航运业。研究人员将开发这样一种方法，使用导电超滤膜，将电荷直接传递到膜/水界面。这种电荷的应用，结合适当放置的反电极，产生影响乳化油滴的形状、行为和界面性质的电场。受影响的油滴不再有助于膜污染，允许水通过。本项目的第一个目标是了解乳化油在膜过滤过程中施加电场和流场的行为如何影响分离性能和污染。第二个目标集中在显著增加超滤膜的电导率，这将降低施加电场的能量需求。该项目的完成将开发必要的基础知识，以设计和实施压力驱动的，基于膜的，油/水分离过程，通过电改性膜表面和乳化油滴来减轻膜污染。研究团队还将通过他们的退伍军人研究经验计划为残疾退伍军人提供重要的STEM管道。他们将与加州大学洛杉矶分校的可持续教育中心合作，识别和招募寻求暑期研究实习的残疾退伍军人。这些资深学生将参加一个为期12周的暑期项目，将他们融入研究人员的实验室，并为他们提供一个进行研究生水平研究的机会，希望鼓励他们在STEM领域攻读高级学位。 本项目将探索电过滤和乳化油动力学的结合，以开发抗结垢的油/水分离工艺为目标。由于许多乳化剂带有电荷，因此预期它们将响应于外部电场，这将影响乳化油滴本身的界面性质。了解这些复杂的系统如何响应外部场（电场和流动）将有助于阐明基本的乳化特性，并有可能改善使用乳化油的多种工艺。该项目还将探索如何增加碳纳米管的导电性（使用导电聚合物，金属离子嵌入或金属沉积）影响碳纳米管/聚合物导电膜的整体表面和传输性能。最大化通过膜的导电性和传输将使得能够沿膜表面沿着有效且均匀的电荷分布，这将使得能够无污垢操作，同时降低工艺能量消耗。电场对沿沿着膜表面积聚的油滴的界面性质的影响的基础知识的发展具有改变基于膜的油/水分离过程的潜力。该项目涉及来自美国和以色列的两个团队。教授来自洛杉矶的加州大学的大卫·贾斯比和埃里克·霍克得到了化学、生物工程、环境和运输系统部门的分子分离、颗粒和多相过程项目的支持。Guy Ramon教授，来自以色列理工学院，由美国-以色列两国科学基金会。该奖项反映了NSF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 separation of emulsified oil from waste water streams remains a significant industrial challenge. Membrane filtration is one of the few methods that can remove emulsified oil drops. However, the filtration of these drops is complicated by severe membrane fouling, where fluid passage through the membrane is slowed by particles or solutions at the surface. Developing an energy-efficient separation process for removing emulsified oil from water with minimal membrane fouling would benefit many industrial users, including oil and gas producers, food processors, and the shipping industry. The investigators will develop such a process using electrically-conducting ultrafiltration membranes that deliver an electric charge directly to the membrane/water interface. The application of this charge, combined with an appropriately placed counter-electrode, generates electric fields that impact the shape, behavior, and interfacial properties of emulsified oil drops. The affected oil drops no longer contribute to membrane fouling, allowing water to pass through. The first goal of this project is to understand how emulsified oil behavior during membrane filtration with applied electric- and flow-fields influences separation performance and fouling. The second goal focuses on dramatically increasing the conductivity of the ultrafiltration membranes, which will lower the energy requirements of applying an electric field. Completion of the project will develop the fundamental knowledge necessary to design and implement a pressure-driven, membrane-based, oil/water separation process that mitigates membrane fouling by electrically modifying both the membrane surface and emulsified oil drops. The research team will also provide an important STEM pipeline for disabled military veterans through their Research Experience for Veterans Program. They will partner with the University of California, Los Angeles's Center for Accessible Education to identify and recruit disabled veterans seeking a summer research internship. These veteran students will participate in a 12-week summer program that will integrate them into the investigators' laboratories and provide them an opportunity to do graduate-level research in hopes of encouraging them to pursue an advanced degree in a STEM field. This project will explore the combination of electrofiltration and emulsified oil dynamics, with the goal of developing a fouling-resistant oil/water separation process. Since many emulsifying agents carry an electrical charge, it is expected that they will respond to an external electrical field, which will impact the interfacial properties of the emulsified oil drops themselves. Understanding how these complex systems respond to external fields (both electrical and flow) will help elucidate fundamental emulsion properties, with the potential of improving multiple processes where emulsified oils are used. The project will also explore how increasing the conductivity of a percolating network of carbon nanotubes (using conducting polymers, metal ion intercalation, or metal deposition) impacts the overall surface and transport properties of carbon nanotube/polymer electrically-conducting membranes. Maximizing conductivity and transport through the membrane will enable efficient and uniform charge distribution along the membrane surface, which will enable fouling-free operation while decreasing process energy consumption. Developing fundamental knowledge of the impact of electrical fields on the interfacial properties of oil drops accumulated along the membrane surface coupled with highly-conducting porous polymeric materials has the potential of transforming membrane-based oil/water separation processes. The project involves two teams from the U.S. and Israel. Profs. David Jassby and Eric Hoek, from the University of California, Los Angeles, are supported by the Molecular Separations and Particulate and Multiphase Processes programs in the Division of Chemical, Bioengineering, Environmental, and Transport Systems. Prof. Guy Ramon, from Technion-Israel Institute of Technology, is supported by the U.S.-Israel Binational Science Foundation.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.