Fundamental Water and Ion Transport Properties in Polymers for Membrane Applications

膜应用聚合物的基本水和离子传输特性

• 批准号: 1160128
• 负责人: Benny Freeman
• 金额: $ 30.74万
• 依托单位: University of Texas at Austin
• 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: 2012-05-15 至 2017-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1160128&HistoricalAwards=false
• 关键词: Fundamental; Water; Ion; Transport; Properties

Intellectual Merit: According to the National Academy of Engineering, one of the ?Grand Challenges for Engineering? is providing access to clean water for mankind.1 The development of energy-efficient methods to provide adequate access to clean water for a variety of agricultural, industrial and municipal applications is an urgent and critical problem in many parts of the world. Polymer membranes play a central role in water purification today, and because they are often more energy-efficient than conventional technologies, their role in water purification is increasing. A key challenge in purifying water from brackish or seawater sources is removal of ions (i.e., desalination). While reverse osmosis (RO) membranes are widely used for desalination, there are a plethora of other membrane-based techniques (e.g., forward osmosis, electrodialysis, reverse electrodialysis, and membrane-assisted capacitive deionization) that could contribute significantly to water purification and power generation in the future. However, much remains unknown about even basic relationships between polymer structure and ion and water transport properties, and such information is critical for rationally tailoring new membranes for such applications. Therefore, the experimental research project will investigate fundamental water and salt transport properties in a variety of polymers to develop structure-property relationships to assist in designing and optimizing next generation polymer membranes for water/ion separations. For desalination membrane materials, one objective of the proposed program will be to understand how polymer structures can be optimized to simultaneously increase water permeability while maintaining or decreasing salt permeability. The project will consider a variety of materials to span a wide polymer structure spectrum. The influence of polymer charge, backbone rigidity, cross-linking, and morphology/polymer architecture (e.g., block copolymers) on water and ion transport properties will be studied. The investigators will also characterize the impact of mono-/divalent ion concentration on water and ion transport properties. Results from these studies will provide fundamental structure/property relations to guide the rational tailoring of polymers for desalination or other applications, such as those mentioned above. When possible, experimental results will be compared with existing models. In this regard, available models, such as free volume theory (for water and ion diffusion properties) and Donnan equilibrium (for ion partitioning), will be used in data analysis/interpretation to construct and validate a systematic, fundamental framework for organizing experimental data into structure/property correlations that can be used to guide selection of next-generation structures with more favorable property profiles for a given application. The proposed research program is well suited for developing fundamental knowledge and understanding through systematic hypothesis-driven studies. Broader Impacts: The proposed study will include STEM education programs for pre-K through undergraduate students, and students from underrepresented groups will be encouraged to participate in these opportunities. For example, The investigators will organize separations modules to be presented at Science Sundays at the Austin Children?s Museum, which reaches a broad spectrum of children, including many children of Hispanic origin. They will also partner with the Texas School for the Deaf to bring hearing-impaired high school students to their laboratories for after-school and summer research experiences. All students engaging in the proposed research program or the outreach programs will gain critical research skills while formulating, conducting, and analyzing data from hypothesis-driven experiments. Results will be published in the peer-reviewed and, when appropriate, patent literature so that the knowledge gained during the proposed program will be available to guide and educate future researchers. We would also present the work at scientific conferences. Society-at-large will benefit because improved fundamental understanding of relationships between polymer structure and water/ion transport properties will enable more rapid development of improved polymers for desalination and other membrane-based processes involving water and ion transport. In desalination, such membranes could provide populations in water-stressed regions with critically needed water while reducing the energy and environmental cost of desalination.

智力优势：根据美国国家工程院的说法，是世界上最好的？工程的巨大挑战？1在世界许多地区，开发节能方法，为各种农业、工业和市政应用提供充分的清洁用水，是一个紧迫和关键的问题。聚合物膜在当今的水净化中发挥着核心作用，并且由于它们通常比传统技术更节能，因此它们在水净化中的作用正在增加。从微咸或海水来源净化水的关键挑战是去除离子（即，脱盐）。虽然反渗透（RO）膜广泛用于脱盐，但存在过多的其他基于膜的技术（例如，正向渗透、电渗析、反向电渗析和膜辅助电容去离子），其可在未来显著地有助于水净化和发电。然而，仍然有很多未知的，甚至是基本的聚合物结构和离子和水的传输性能之间的关系，这些信息是至关重要的，合理定制新的膜，这样的应用。因此，该实验研究项目将研究各种聚合物的基本水和盐传输特性，以开发结构-性能关系，以帮助设计和优化下一代水/离子分离聚合物膜。对于脱盐膜材料，拟议计划的一个目标是了解如何优化聚合物结构，以同时提高水渗透性，同时保持或降低盐渗透性。该项目将考虑各种材料，以跨越广泛的聚合物结构谱。聚合物电荷、主链刚性、交联和形态/聚合物结构（例如，嵌段共聚物）对水和离子传输性能的影响。研究人员还将表征一价/二价离子浓度对水和离子传输特性的影响。这些研究的结果将提供基本的结构/性能关系，以指导用于脱盐或其他应用的聚合物的合理定制，例如上述那些。在可能的情况下，将实验结果与现有模型进行比较。在这方面，可用的模型，如自由体积理论（水和离子扩散特性）和唐南平衡（离子分配），将用于数据分析/解释，以构建和验证一个系统的，基本的框架，组织实验数据到结构/性能的相关性，可用于指导下一代结构的选择与更有利的属性配置文件为给定的应用程序。拟议的研究计划非常适合通过系统的假设驱动的研究发展基础知识和理解。更广泛的影响：拟议的研究将包括针对学前班到本科生的STEM教育计划，并鼓励来自代表性不足群体的学生参与这些机会。例如，调查人员将组织分离单元在科学星期日在奥斯汀儿童？博物馆，它触及广泛的儿童，包括许多西班牙裔儿童。他们还将与德克萨斯州聋人学校合作，将听力受损的高中生带到他们的实验室进行课后和夏季研究体验。所有参与拟议的研究计划或外展计划的学生将获得关键的研究技能，同时制定，进行和分析来自假设驱动的实验数据。研究结果将发表在同行评议的专利文献中，以便在拟议的计划中获得的知识可用于指导和教育未来的研究人员。我们还将在科学会议上介绍这项工作。整个社会都将受益，因为对聚合物结构和水/离子传输特性之间关系的基本理解的提高将使用于脱盐和其他涉及水和离子传输的膜基工艺的改进聚合物的开发更加迅速。在脱盐方面，这种膜可以为缺水地区的人口提供急需的水，同时减少脱盐的能源和环境成本。