CAREER: Charge Delocalization: A New Tool for Controlling Ionic Selectivity and Conductivity of Ion-Exchange Membranes

职业：电荷离域：控制离子交换膜的离子选择性和电导率的新工具

• 批准号: 2237122
• 负责人: Jovan Kamcev
• 金额: $ 54.97万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-01 至 2028-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2237122&HistoricalAwards=false
• 关键词: CAREER; Charge; Delocalization; New; Tool

Management of highly impaired waters (i.e., waters that contain high concentrations of salts and other dissolved solutes) is critical for applications such as water desalination and hydraulic fracturing. The difficulty of brine management hinders the growth of such applications, which ultimately affects the water and energy security of our Nation. Electrodialysis, a membrane-based technology that uses charged polymer membranes and electricity to separate ions, removing them from water, has been proposed for treating highly impaired waters. However, this technology is energy intensive and inefficient because the membrane performance significantly deteriorates when contacted by highly impaired waters. In this study, the connection between the chemical identity of the charged groups on the polymer backbone and the membrane performance will be systematically investigated. The development of such structure/property relationships will guide the design of membranes with improved transport properties when contacted by highly impaired waters. To enhance the involvement of low socioeconomic status students in STEM, a comprehensive summer research program for high school students will be developed. The program will involve hands-on laboratory work, a short course on membrane science, and dissemination of the results to a broad and diverse audience via outreach programs developed via a collaboration with the University of Michigan Museum of Natural History.Ion-exchange membranes (IEMs) that are used for treating highly impaired waters via electrodialysis contain low amounts of water. There is evidence of ion pairing in such materials, which ultimately decreases the charge density of the membrane and worsens both the ionic conductivity and selectivity. Increasing the charge delocalization of the fixed charge groups is hypothesized to enhance both the ionic conductivity and selectivity of low water content IEMs by weakening electrostatic interactions between the fixed charges and mobile ions. This hypothesis will be systematically tested via a combined experimental and modeling study on the influence of charge delocalization on transport properties of IEMs. The majority of IEMs for aqueous ion separations utilize sulfonate anions or trimethylammonium cations as the charged groups attached to the polymer backbone, so the proposed project will open up a new direction of study on IEMs for aqueous ion separations. Due to the fundamental nature of the proposed study, the knowledge generated will have broad implications for other technologies that use IEMs in low dielectric environments (e.g., energy conversion and storage devices).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.

高度受损水域（即含有高浓度盐和其他溶解溶质的水域）的管理对于海水淡化和水力压裂等应用至关重要。盐水管理的困难阻碍了此类应用的增长，最终影响了我们国家的水和能源安全。电渗析是一种基于膜的技术，利用带电聚合物膜和电力来分离离子，将其从水中去除，已被提议用于处理严重受损的水体。然而，该技术能源密集且效率低下，因为当与高度受损的水接触时，膜性能会显着恶化。在这项研究中，将系统地研究聚合物主链上带电基团的化学特性与膜性能之间的联系。这种结构/性能关系的发展将指导膜的设计，当与严重受损的水接触时，其传输性能得到改善。为了提高社会经济地位较低的学生参与 STEM，将为高中生制定综合性暑期研究计划。该计划将包括实验室实践工作、膜科学短期课程，以及通过与密歇根大学自然历史博物馆合作开发的推广计划向广泛和多样化的受众传播结果。离子交换膜（用于通过电渗析处理严重受损水体的 IEM 含有少量水。有证据表明此类材料中存在离子配对，这最终会降低膜的电荷密度并恶化离子电导率和选择性。假设增加固定电荷基团的电荷离域，可以通过削弱固定电荷和移动离子之间的静电相互作用来增强低含水量 IEM 的离子电导率和选择性。该假设将通过实验和建模相结合的研究来系统地检验，研究电荷离域对 IEM 输运特性的影响。大多数用于水性离子分离的IEM利用磺酸根阴离子或三甲基铵阳离子作为附着在聚合物主链上的带电基团，因此该项目将为水性离子分离的IEM开辟新的研究方向。由于拟议研究的基本性质，所产生的知识将对在低介电环境中使用 IEM 的其他技术（例如能量转换和存储设备）产生广泛的影响。该奖项反映了 NSF 的法定使命，并被认为值得支持通过使用基金会的智力优点和更广泛的影响审查标准进行评估。