Porter Cassandra J, Werber Jay R, Zhong Mingjiang, Wilson Corey J, Elimelech Menachem
Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States.
Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States.
ACS Nano. 2020 Sep 22;14(9):10894-10916. doi: 10.1021/acsnano.0c05753. Epub 2020 Sep 11.
Transmembrane protein channels, including ion channels and aquaporins that are responsible for fast and selective transport of water, have inspired membrane scientists to exploit and mimic their performance in membrane technologies. These biomimetic membranes comprise discrete nanochannels aligned within amphiphilic matrices on a robust support. While biological components have been used directly, extensive work has also been conducted to produce stable synthetic mimics of protein channels and lipid bilayers. However, the experimental performance of biomimetic membranes remains far below that of biological membranes. In this review, we critically assess the status and potential of biomimetic desalination membranes. We first review channel chemistries and their transport behavior, identifying key characteristics to optimize water permeability and salt rejection. We compare various channel types within an industrial context, considering transport performance, processability, and stability. Through a re-examination of previous vesicular stopped-flow studies, we demonstrate that incorrect permeability equations result in an overestimation of the water permeability of nanochannels. We find in particular that the most optimized aquaporin-bearing bilayer had a pure water permeability of 2.1 L m h bar, which is comparable to that of current state-of-the-art polymeric desalination membranes. Through a quantitative assessment of biomimetic membrane formats, we analytically show that formats incorporating intact vesicles offer minimal benefit, whereas planar biomimetic selective layers could allow for dramatically improved salt rejections. We then show that the persistence of nanoscale defects explains observed subpar performance. We conclude with a discussion on optimal strategies for minimizing these defects, which could enable breakthrough performance.
跨膜蛋白通道，包括负责水的快速和选择性运输的离子通道和水通道蛋白，启发了膜科学家在膜技术中利用并模仿它们的性能。这些仿生膜由排列在坚固支撑体上的两亲性基质中的离散纳米通道组成。虽然生物成分已被直接使用，但人们也进行了大量工作来制备蛋白质通道和脂质双层的稳定合成模拟物。然而，仿生膜的实验性能仍远低于生物膜。在本综述中，我们批判性地评估了仿生脱盐膜的现状和潜力。我们首先回顾通道化学及其传输行为，确定优化水渗透性和盐截留率的关键特性。我们在工业背景下比较了各种通道类型，考虑了传输性能、可加工性和稳定性。通过重新审视以前的囊泡停流研究，我们证明不正确的渗透性方程会导致对纳米通道水渗透性的高估。我们特别发现，最优化的含 aquaporin 的双层膜的纯水渗透率为 2.1 L m h bar，这与当前最先进的聚合物脱盐膜相当。通过对仿生膜形式的定量评估，我们分析表明，包含完整囊泡的形式益处最小，而平面仿生选择性层可以显著提高盐截留率。然后我们表明，纳米级缺陷的持续存在解释了观察到的不佳性能。我们最后讨论了最小化这些缺陷的最佳策略，这可能实现突破性性能。
