NSF-BSF: Selective Transport of Divalent Cations through Polymeric Membranes Using Host-Guest Chemistry

NSF-BSF：利用主客体化学选择性通过聚合物膜传输二价阳离子

• 批准号: 2110138
• 负责人: Menachem Elimelech
• 金额: $ 41.32万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2110138&HistoricalAwards=false
• 关键词: NSF; BSF; Selective; Transport; Divalent

Producing drinking water from unconventional water sources, such as seawater, brackish water, and municipal wastewater effluent, is crucial for alleviating global water scarcity. Polymeric membranes, such as thin-film composite reverse osmosis (RO) membranes, have been at the forefront of water purification and desalination processes since their advent in the early 1980s. While RO systems are energy efficient and consume only ~25% more than the practical minimum theoretical energy of desalination, RO membranes are susceptible to inorganic scaling caused by scale-forming ions such as sulfate and divalent calcium, magnesium, or barium. Source waters that have high concentrations of these ions and/or require high recovery rates, such as in inland desalination, have an exceptionally high propensity to produce inorganic scale on membranes. Inorganic scaling is known to drastically lower membrane water flux, limit membrane lifetime, increase treatment costs, and increase the energy consumption of membrane processes. Economic and environmental effects of membrane scaling have led to various mitigation approaches, including adjusting solution pH and adding polymeric antiscalants to block crystal growth sites. However, the primary limitation of established techniques is they require the addition of chemicals, such as polymers or strong acids/bases, that are environmentally unfriendly and costly. In collaboration with researchers at Ben-Gurion University, this project will address the imminent need for an alternative, chemical-free method to selectively remove scale-forming ions to mitigate scaling on RO membrane surfaces and improve the economics of desalination processes.The overall goal of the research is to translate selectivity mechanisms of biological channels into polymeric membranes for the purpose of selectively removing scale-forming species in a continuous electrodialysis process. The investigators hypothesize that molecular binding sites that can selectively remove water shells from ions (as seen in some biological channels) will enable highly specific adsorption and transport through membranes. To test this hypothesis, a selective membrane will be created by modifying the surface of conventional membranes with polymers comprising pendant groups with a high chemical affinity for target ions (Task 1). These functional groups are expected to yield unprecedented selectivity because they provide favorable host-guest complexes to selectively remove water shells of target ions (Task 2). This functional prototype will then be used to elucidate selectivity mechanisms for membranes with host-guest chemistry (Task 3), as well as to assess the relationship between the structural properties of those membranes and their selective transport (Task 4). Finally, the insights from Tasks 1-4 will be used to develop a homogenous membrane (Task 5), which will then be tested in electrodialysis for selective removal of scale-forming ions (Task 6). The specific objectives of the project include: (i) investigating the role of ion affinity to chemically tailored polymers in achieving selective transport, (ii) assessing how intrinsic membrane structural properties affect solute transport and selectivity, and (iii) fabricating robust membranes to reduce scaling potential using electrodialysis. The outcome of the project will be a new membrane technology capable of removing scale-forming ions prior to desalination to mitigate scaling on RO membranes. This technology would be the first continuous approach for separating divalent ions from monovalent ions without requiring periodic use of chemicals, overcoming the limitations of existing approaches. This study will also advance the fundamental understanding of selective transport processes by applying transition-state theory to describe solute transport phenomena in terms of entropy and enthalpy. These insights, along with design principles established from this study, will be relevant for separations of other solutes as well, which may later find application in reclaiming valuable resources or removing contaminants of concern from water. This research is jointly funded by NSF and The US-Israel Binational Science foundation through the special submission opportunity NSF 20-094.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.

从非常规的水源产生饮用水，例如海水，咸水和市政废水，对于减轻全球水稀缺至关重要。自1980年代初出现以来，聚合物膜，例如薄膜复合逆渗透（RO）膜，一直处于水纯化和脱盐过程的最前沿。虽然RO系统具有节能性，并且仅比实际的最低理论能量高出约25％，但RO膜易受尺度形成离子（如硫酸盐和除多钙，镁，镁或钡）引起的无机缩放尺度。具有高浓度的这些离子和/或需要高回收率的源水（例如内陆海水淡化）具有极高的倾向，可以在膜上产生无机尺度。已知无机缩放会大大降低膜水通量，限制膜寿命，增加治疗成本并增加膜过程的能源消耗。膜缩放的经济和环境影响导致了各种缓解方法，包括调整溶液pH值和添加聚合物抗混蛋以阻止晶体生长位点。但是，已建立技术的主要局限性是它们需要添加化学物质，例如聚合物或强酸/碱，这些化学物质在环境上是不友好和昂贵的。该项目与本古里翁大学的研究人员合作，将解决一种替代性，无化学物质的方法的需求，以选择性地去除尺度形成的离子，以减轻Ro膜表面上的扩展，并改善脱水过程的经济性。该研究的总体目标是，研究的整体方法是对量表进行量表的量表，以使量表进行量表，以使量表进行量表，从而选择性地衡量量表的量表，以选择一定的量表，以使一定的量表范围用于一定的量表。 过程。研究者假设可以选择性地从离子中去除水壳的分子结合位点（如在某些生物学通道中所见）将使高度特异性的吸附和通过膜传输。为了检验这一假设，将通过与包含对靶离子具有高化学亲和力的吊坠基团的传统膜表面来修饰常规膜的表面来产生选择性膜（任务1）。这些官能团有望产生前所未有的选择性，因为它们提供了有利的宿主 - 阵阵复合物来选择性地去除目标离子的水壳（任务2）。然后，该功能原型将用于阐明具有宿主环化学的膜的选择性机制（任务3），并评估这些膜的结构特性与其选择性传输之间的关系（任务4）。最后，任务1-4的见解将用于开发均匀的膜（任务5），然后将其在电透析中进行测试，以选择性去除尺度形成离子（任务6）。该项目的具体目标包括：（i）研究离子与化学定制聚合物在实现选择性传输中的作用，（ii）评估内在的膜结构特性如何影响溶质传输和选择性，以及（iii）制造强大的膜以使用电溶性使用电势来减少缩放势。该项目的结果将是一种新的膜技术，能够在脱盐之前去除尺度形成离子以减轻对RO膜的缩放。该技术将是将二价离子与单价离子分离而不需要定期使用化学物质的第一种连续方法，从而克服了现有方法的局限性。这项研究还将通过应用过渡状态理论来描述溶质运输现象，以熵和焓来描述溶质传输现象，从而提高对选择性运输过程的基本理解。这些见解以及本研究确定的设计原则也将与其他溶质的分离有关，后来可能会在收回宝贵的资源或从水中消除关注的污染物中的应用。这项研究是由NSF和美国 - 以色列双性科学基金会通过特别提交机会NSF共同资助的。20-094。该奖项反映了NSF的法定任务，并被认为是通过基金会的智力优点和更广泛影响的审查标准通过评估来通过评估来支持的。

项目成果

Prospects of metal recovery from wastewater and brine

• DOI: 10.1038/s44221-022-00006-z
• 发表时间: 2023-01-01
• 期刊: Nat. Water
• 作者: DuChanois, R.M.;Cooper, N.J.;Elimelech, M.
• 通讯作者: Elimelech, M.