Collaborative Research: Modified Reverse Osmosis Membranes for Forward and Pressure Retarded Osmosis

合作研究：用于正向和压力延迟渗透的改良反渗透膜

• 批准号: 1160098
• 负责人: Jeffrey McCutcheon
• 金额: $ 23.44万
• 依托单位: University of Connecticut
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1160098&HistoricalAwards=false
• 关键词: Collaborative; Research; Modified; Reverse; Osmosis

McCutcheon/Freeman1160098/110069This NSF award by the Chemical and Biological Separations program supports work by Professors Jeffrey McCutcheon and Benny Freeman to develop a new method for chemically modifying commercial reverse osmosis membranes for use in forward osmosis and pressure retarded osmosis applications. Forward osmosis (FO) and pressure retarded osmosis (PRO) are sibling technologies that fall under the broader distinction of engineered osmosis (EO). This platform relies on osmotic flow induced by concentration differences across a membrane to purify water, dewater solutions and generate electricity. FO has recently been considered for seawater desalination, wastewater reuse, and food processing and is considered a low cost alternative to reverse osmosis (RO) and evaporative approaches. PRO has been considered for harvesting osmotic potential at river deltas and within "osmotic engine" systems to generate electricity with a hydroturbine.Any EO technology requires a tailored membrane that not only is highly selective, but also exhibits properties that promote osmotic flow. Today's commercial desalting membranes are designed specifically for reverse osmosis. These membranes exhibit excellent selectivity and permeability, but also employ thick porous support layers. These layers provide little resistance to hydraulic flow in RO. However, they dramatically impact mass transfer in forward osmosis, causing what is commonly referred to as internal concentration polarization. Early work has shown that RO membranes have very poor flux performance when evaluated in FO or PRO. A significant amount of this resistance is caused by poor wetting of the support layers, which are comprised of hydrophobic polymers.This work will demonstrate that a chemical modification of reverse osmosis membrane support layers with polydopamine and its analogs will enhance osmotic flux by increasing the hydrophilicity of the support layers. Once hydrophilized, the layers will saturate, thereby providing the necessary continuity of the water phase to reduce mass transfer resistances. Early work has already shown that in some cases, water flux can be increased by a factor of 10 or more when compared to an unmodified membrane. This solution may provide an alternative to building new membranes using techniques that may be difficult to scale or will require years of development to achieve similar performance to today's RO membranes.In a world of ever increasing demand for scarce water and energy resources, new technology platforms, like EO, offer new possibilities. Desalination and power production using EO will be enabled through the development of new, tailored membranes. However, if we are able to use existing membrane technology with a simple modification, we do not need to develop an entirely new membrane platform. In fact, the proposed modification method is scalable and therefore easily implemented into existing membrane productions lines. Membrane manufacturers are more likely to implement changes to their production scheme if it doesn't require rebuilding their entire manufacturing infrastructure. Furthermore, this investigation will represent the first time that modification of a RO membrane support layer has been considered to increase flux performance.To achieve our goals, a better understanding of how the coating occurs within a porous material (the RO membrane support layer) will be necessary. The University of Connecticut will evaluate the coating procedure to maximize performance improvements while the University of Texas will develop analog chemistries to polydopamine that may be more appropriate for deposition within a porous structure. Ultimately, we will develop an understanding of how chemistry and modification technique impact osmotic flux performance across modified RO membranes.According to the National Academy of Engineering, one of the Grand Challenges for Engineering is providing access to clean water for mankind. The development of emerging water treatment technologies like forward osmosis could reinvigorate interest in desalination and wastewater reuse due to its promised benefits of low cost. As such, both PIs will use this work to stimulate interest in water within their educational and outreach programs. At the University of Texas, Professor Freeman will provide research opportunities for high school students and teachers, giving invaluable experience to help promote engineering education in Texas high schools. At the University of Connecticut, Professor McCutcheon will be an active participant in Universitas 21, an organization that promotes undergraduate research across disciplines and oceans. Twenty three member universities provide programming for undergraduates to present their research, and UCONN is one of two American university participants. Professor McCutcheon will help develop programming for a summer school to be held at UCONN as well as mentor the UCONN undergraduates who plan on attending the annual conference and other meetings. The PIs will collaborate in establishing an REU exchange program, called UCONNect2Texas, which will involve undergraduate students from each school visiting the other for a period of 10 weeks during the summer.

由化学和生物分离项目授予的NSF奖支持Jeffrey McCutcheon教授和Benny Freeman教授开发一种化学修饰商业反渗透膜的新方法，用于正向渗透和压力延迟渗透应用。正向渗透（FO）和压力延迟渗透（PRO）是兄弟技术，属于工程渗透（EO）的更广泛的区别。该平台依靠由膜上的浓度差异引起的渗透流来净化水、脱水溶液和发电。FO最近被考虑用于海水淡化、废水回用和食品加工，被认为是反渗透（RO）和蒸发方法的低成本替代品。PRO已被考虑用于收集河流三角洲和“渗透发动机”系统中的渗透势，以利用水力涡轮机发电。任何EO技术都需要定制的膜，不仅具有高选择性，而且还具有促进渗透流动的特性。今天的商业脱盐膜是专门为反渗透设计的。这些膜具有优异的选择性和渗透性，但也采用厚的多孔支撑层。这些层对RO中的水力流动提供很小的阻力。然而，它们在正向渗透中显著地影响传质，造成通常所说的内部浓度极化。早期的工作表明，当在FO或PRO中进行评估时，RO膜的通量性能非常差。这种阻力的很大一部分是由由疏水聚合物组成的支撑层润湿性差引起的。这项工作将证明用聚多巴胺及其类似物对反渗透膜支持层进行化学修饰将通过增加支持层的亲水性来增强渗透通量。一旦亲水性，层将饱和，从而提供必要的水相连续性，以减少传质阻力。早期的工作已经表明，在某些情况下，与未经修饰的膜相比，水通量可以增加10倍或更多。该解决方案可能为使用难以扩展或需要多年开发才能达到与当今反渗透膜相似性能的技术构建新膜提供了一种替代方案。在一个对稀缺的水和能源需求不断增长的世界，像EO这样的新技术平台提供了新的可能性。通过开发新型定制膜，EO将用于海水淡化和发电。然而，如果我们能够利用现有的膜技术进行简单的修改，我们就不需要开发一个全新的膜平台。事实上，所提出的改性方法是可扩展的，因此很容易在现有的膜生产线上实施。如果不需要重建整个生产基础设施，膜制造商更有可能对其生产计划进行更改。此外，该研究将首次考虑对反渗透膜支撑层进行改性以提高通量性能。为了实现我们的目标，有必要更好地了解涂层如何在多孔材料（反渗透膜支撑层）中发生。康涅狄格大学将评估涂层过程，以最大限度地提高性能，而德克萨斯大学将开发聚多巴胺的模拟化学物质，这种化学物质可能更适合在多孔结构中沉积。最后，我们将了解化学和改性技术如何影响改性反渗透膜的渗透通量性能。根据美国国家工程院的说法，工程学的重大挑战之一是为人类提供清洁的水。正渗透等新兴水处理技术的发展可能会重新激发人们对海水淡化和废水再利用的兴趣，因为它有望带来低成本的好处。因此，这两个pi将利用这项工作在他们的教育和推广项目中激发对水的兴趣。在德克萨斯大学，Freeman教授将为高中学生和教师提供研究机会，为促进德克萨斯高中的工程教育提供宝贵的经验。在康涅狄格大学，麦卡琴教授将积极参与Universitas 21，这是一个促进跨学科和跨海洋本科生研究的组织。23所成员大学为本科生提供展示研究成果的项目，康涅狄格大学是两所美国大学之一。McCutcheon教授将帮助制定在康涅狄格大学举办的暑期学校的计划，并指导康涅狄格大学计划参加年度会议和其他会议的本科生。这两所大学将合作建立一个名为UCONNect2Texas的REU交流项目，该项目将让两所学校的本科生在夏季访问对方学校，为期10周。