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Computational Design of Ultraselective Desalination Membranes using Molecular Simulations and Path Sampling Techniques

使用分子模拟和路径采样技术的超选择性脱盐膜的计算设计

基本信息

批准号：
2024473
负责人：
Amir Haji-Akbari
金额：
$ 33.24万
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：
2021-01-01 至 2023-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2024473&HistoricalAwards=false
关键词：
Computational Design Ultraselective Desalination Membranes

项目摘要

Semipermeable membranes selectively impede the passage of undesirable molecules and ions in a fluid, while allowing the desirable molecules to pass through the membrane. This type of technology is key to many applications as well as natural processes. For instance, membranes that are only water permeable and reject most other ions and molecules are used in water desalination. Similarly, biological cells feature membranes capable of modulating the passage of small molecules and ions into and out of the cell. On a molecular level, a membrane’s selectivity is dictated by its nanostructure, i.e., the geometry, topology, and chemistry of its constituent nanopores. However, there is much yet to learn about how a membrane's structure is fundamentally related to its selectivity for certain ions and molecules. On one hand, existing experimental techniques lack the necessary spatiotemporal resolution to characterize membrane structure and to probe isolated solute (the molecule or ion) passage events. On the other hand, conventional molecular simulation techniques can provide information about events at the correct length-scale, but the average time it takes to observe an undesirable solute passing through a highly selective membrane is beyond the reach of standard molecular simulation methods. These factors limit our ability to understand important natural processes (such as biological membrane transport and solute transport in porous media) and hamper efforts to rationally design ultraselective membranes for desalination and gas and chemical separation applications.The goal of this proposal is to conduct a systematic investigation of the structure-selectivity relationship in nanoporous membranes using molecular dynamics simulations and advanced path sampling techniques. The investigator recently developed a novel path sampling algorithm that makes it possible to accurately and efficiently estimate arbitrarily long solute transport timescales under operationally realistic conditions. The algorithm is also capable of reconstructing an accurate and statistically representative picture of the solute transport mechanism. This approach will be used to probe the kinetics and molecular mechanisms of pressure-driven solute transport through nanoporous membranes with well-defined geometries and chemistries. The project focuses on membranes used in desalination applications, but the developed computational tools can be universally applied to other membrane-based separation processes. The research plan sets out first to develop new computational tools and methods for studying solute transport through membranes. Subsequently, the investigator will conduct a set of hypothesis-based calculations that address important fundamental questions about the structure-selectivity relationship in membranes and hindered transport under nanoscale confinement. To this end, both simple model carbon-based membranes with well-defined structures and chemistries and synthetic membranes such as zeolites and metal-organic frameworks will be examined. Collaboration with experimental groups at Yale complements the modeling efforts, as membranes with well-defined structures will be synthesized and performance in membrane-based desalination will be assessed.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.

半透膜选择性地阻止流体中不受欢迎的分子和离子通过，同时允许所需的分子通过膜。这种类型的技术对许多应用以及自然过程都是关键。例如，只有透水性的膜才能阻挡大多数其他离子和分子，这种膜可用于海水淡化。类似地，生物细胞具有能够调节小分子和离子进出细胞的通道的膜。在分子水平上，膜的选择性取决于其纳米结构，即其组成纳米孔的几何、拓扑和化学。然而，关于膜的结构如何从根本上与其对某些离子和分子的选择性有关，还需要了解很多。一方面，现有的实验技术缺乏必要的时空分辨率来表征膜结构和探测孤立的溶质(分子或离子)通过事件。另一方面，传统的分子模拟技术可以在正确的长度尺度上提供事件的信息，但观察到不希望的溶质通过高选择性膜所需的平均时间超出了标准分子模拟方法的范围。这些因素限制了我们理解重要的自然过程(如生物膜在多孔介质中的传输和溶质传输)的能力，并阻碍了合理设计用于海水淡化和气体和化学分离应用的超选择性膜的努力。本提议的目标是利用分子动力学模拟和先进的路径采样技术对纳米孔膜中的结构-选择性关系进行系统的研究。研究人员最近开发了一种新的路径采样算法，使得在实际操作条件下准确和有效地估计任意长的溶质运移时间尺度成为可能。该算法还能够重建准确的、具有统计代表性的溶质运移机制的图像。这种方法将被用来探索压力驱动的溶质通过具有明确几何和化学结构的纳米孔膜的动力学和分子机制。该项目的重点是用于海水淡化应用的膜，但开发的计算工具可以普遍应用于其他基于膜的分离过程。该研究计划首先开发新的计算工具和方法，以研究溶质通过膜的传输。随后，研究人员将进行一系列基于假设的计算，以解决关于膜中结构-选择性关系和纳米尺度限制下的受阻传输的重要基本问题。为此，我们将考察具有明确结构和化学性质的简单碳基模型膜，以及沸石和金属有机骨架等合成膜。与耶鲁大学实验小组的合作是对建模工作的补充，因为将合成具有明确结构的膜，并将评估基于膜的海水淡化的性能。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。