NSF/DMR-BSF: Understanding transport in biomimetic carbon nanotube porin membranes for water treatment and osmotic energy harvesting

非技术：虽然世界上大多数地方都是由水组成的，但人类消费的水在使用之前几乎总是需要某种形式的净化。鉴于不断增长的全球需求，获得清洁水是一个世界性的问题，需要新的技术来满足需求，同时降低成本。由于海洋仍然是唯一真正取之不尽、用之不竭的水源，反渗透海水淡化仍将是美国及其他地区可持续水解决方案的重要组成部分。此外，在淡水资源稀缺的地方，如以色列、中东或美国西部，海水淡化成为一个关键组成部分。虽然海水淡化解决方案在市场上已经存在了50多年，但大多数商业反渗透海水淡化装置仍然依赖于数十年前的膜技术，这种技术很可能在几年前就达到了其有用的极限。在这项美国和以色列的联合项目中，研究人员将开发一种新型膜，通过让水分子通过直径不到人类头发百万分之一的非常小的碳纳米管，高效、快速地去除水中的盐。纳米管不仅很小，而且非常有效，比任何其他已知的孔传递水的速度都要快。拟议中的研究还将采用一种完全不同的方法，模仿最好的膜生物膜(活细胞的外膜)的结构，并应对现有的用于净水的细胞膜进行重大改进。这项调查的一个重要部分将涉及向本科生和K-12年级的学生宣传水技术的重要性，培训美国和以色列的研究生掌握最先进的仿生技术，并开发一个美国-以色列联合暑期学校，学生可以在其中向水净化研究的全球领先者学习。技术：这个合作项目汇集了两个总部设在美国的生物材料/纳米孔小组(Noy，Wanunu)和一个以色列膜科学小组(Freger)，将开发一个强大的仿生膜平台，模拟细胞膜的分级组织，并利用碳纳米管多孔材料的高效和选择性传输。具体地说，将设计和制造包含嵌入在可渗透膜支撑物上的薄基质层中的碳纳米管孔蛋白(CNTP)的膜。这些成分模拟细胞膜的三个主要结构元素：(I)膜孔通道，(Ii)脂双层，和(Iii)细胞骨架。这项研究将在整体和单孔尺度上表征水和离子在这些膜中的传输，主要集中在纳米孔限制实现有效和选择性传输的物理原理。这项研究还将使用化学修饰来改变碳纳米管孔蛋白的选择性。这些膜应该能够增强反渗透(RO)水净化和使用反向电渗析(RED)的渗透发电的膜性能。它们还将允许我们探索现代膜科学中的基本问题，如水传输和离子排斥的物理学，纳米孔中限制的作用，固定电荷的影响，以及浓差极化施加的限制。最后，该项目的外展工作将使我们能够突出基础研究和颠覆性技术进步对确保未来清洁水供应的重要性。这将通过a)创建一个美国-以色列联合暑期班，重点是新的水技术和与水相关的科学基础，b)培训美国研究生和本科生在全球范围内进行水研究。

Non-Technical: While most of the world is made up of water, water for human consumption nearly always requires some form of purification before use. Given the ever-increasing global demand, access to clean water is a world-wide problem that requires novel technologies to keep up with demand at reduced costs. Since the ocean remains the only truly inexhaustible water source, reverse osmosis seawater desalination will remain a vital component of a sustainable water solution in the US and beyond. Moreover, in places with scarce freshwater resources, such as Israel, Middle East, or Western US, desalination becomes a critical component. While desalination solutions have been on the market for more than 50 years, most of commercial reverse osmosis desalination installations still rely on decades-old membrane technology that has likely reached its useful limit years ago. In this joint US/Israel project, the investigators will develop a new kind of membrane that efficiently and quickly removes salt from water by passing water molecules through very small carbon nanotubes with diameters less than one-millionth of a human hair. Nanotubes are not only small, but also extraordinarily efficient, passing water faster than any other known pore. The propose studies also will take a radically-different approach that imitates the structure of the best membrane biological membrane 'the outer membrane of a live cell' and should deliver significant improvements over existing cell membranes for water purification. A vital part of this investigation will involve educational outreach to undergraduate and K-12 students on the importance of water technologies, training US and Israeli graduate students in the state of the art biomimetic technologies, and developing a joint US-Israel summer school in which the students can learn from global leaders in water purification research.Technical: This collaborative project, which brings together two US-based biomaterials/nanopores groups (Noy, Wanunu) and an Israeli membrane science group (Freger), will develop a robust biomimetic membrane platform that mimics hierarchical organization of a cell membrane and exploits highly-efficient and selective transport in carbon nanotube porins. Specifically, membranes that comprise carbon nanotube porins (CNTPs) embedded in a thin matrix layer resting on a permeable membrane support will be designed and fabricated. These components mimic the three main structural elements of a cell membrane: (i) membrane pore channels, (ii) lipid bilayer, and (iii) cytoskeleton. This study will characterize water and ion transport in these membranes on ensemble and single-pore scales, focusing mainly on the physical principles by which nanopore confinement enables efficient and selective transport. This research will also use chemical modification to alter selectivity of the carbon nanotube porins. These membranes should enable enhanced membrane performance for reverse osmosis (RO) water purification and osmotic power generation using reverse electrodialysis (RED). They will also allow us to explore fundamental questions in modern membrane science, such as the physics of water transport and ion exclusion, the role of confinement in nanopores, effects of fixed charges, and limitations imposed by concentration polarization. Finally, outreach efforts in this project will allow us to highlight the importance of basic research and disruptive technological advances for ensuring future availability of clean water. This will be achieved through a) creation of a joint US-Israel summer school that would be focused on new water technologies and fundamentals of water-related science, b) training US graduate and undergraduate students about water research in the global context.