Engineering Atomically Precise Nanochannels Using Layered 2D Sheets to Enable Chemical Separation Membranes with Exceptional Permeance and Size-Selectivity

使用分层二维片设计原子级精确的纳米通道，使化学分离膜具有卓越的渗透性和尺寸选择性

• 批准号: 1705503
• 负责人: Michael Arnold
• 金额: $ 30万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1705503&HistoricalAwards=false
• 关键词: Engineering; Atomically; Precise; Nanochannels; Using

The separation of air into its components, oxygen, nitrogen, carbon dioxide, water vapor, and other trace gases such as helium, is a billion dollar industry. Examples include: use of purified nitrogen in high performance tires and infusion into specialty coffee; use of purified oxygen for healthcare and the launch space shuttles; use of helium for balloons. Separation of any mixture requires both energy and a strategy to isolate one component. Size selective membranes provide one such strategy, allowing molecules to permeate through internal channels at rates that are dictated by their ability to fit within a membrane channel, their diffusivity, and the strength by which they interact with the surface. Decreasing this surface interaction increases permeation, which translates to an increased production rate at lower energy consumption. One candidate for frictionless transport are membrane channels comprised of carbon atoms, such as cylindrical carbon nanotubes or stacked planar graphene sheets. As weak surface interactions provide little impediment to flow, the permeation of water through carbon nanotubes has been experimentally shown to be 1000 times greater than that predicted from classical models. Yet, homogenous channels of closely packed carbon nanotubes have been difficult to synthesize in large quantities. Propped graphene sheets show more promise for large scale synthesis, but are currently derived from graphite via a highly oxidative delamination process, which imparts significant residual oxygen atoms that invalidate frictionless transport. This project will utilize a bottoms-up nonoxidative approach to create propped graphene membranes with controlled channels optimized for size selective transport of small molecules, such as oxygen, nitrogen, hydrogen, helium, and water.This project will use molecular spacers as proppants to synthesize controlled nanochannels between pristine unoxidized parallel graphene sheets. Robust chemistries will be developed for precisely fabricating nanochannels with sub-nanometer gaps that range from 2-8 Angstroms to impart size selectivity. Candidate spacer molecules include para substituted benzene derivatives, functional groups grafted via [2+2] cycloaddition, and non-covalently adsorbed planar and non-planar aromatic hydrocarbons. Both isolated bilayer channels and multilayered laminate membranes will be fabricated. The isolated channels will afford fundamental surface science measurements of structure and properties whereas the multilayered membranes will enable macroscopic measurements of transport to validate the theoretical prediction of frictionless, ultrahigh permeance transport. Microstructural characterization data, in conjunction with transport measurements, will guide design of increasingly effective membrane materials. Both graduate and undergraduate students will perform laboratory research for this project, with an effort to target underrepresented groups. The research will inform interactive lessons targeted at high school level students, accompanied by dissemination of training videos to teachers.

将空气分离成氧气、氮气、二氧化碳、水蒸气和其他微量气体(如氦)，是一个价值数十亿美元的行业。例如：在高性能轮胎和特种咖啡中使用纯氮；在医疗保健和发射航天飞机中使用纯氧；在气球上使用氦。任何混合物的分离都需要能量和分离一种组分的策略。尺寸选择膜提供了一种这样的策略，允许分子以由它们在膜通道内的适应能力、它们的扩散性以及它们与表面相互作用的强度所决定的速率通过内部通道。减少这种表面相互作用会增加渗透率，从而在较低的能源消耗下提高生产率。无摩擦传输的一个候选方案是由碳原子组成的膜通道，例如圆柱形碳纳米管或堆叠的平面石墨烯薄片。由于弱表面相互作用对流动几乎没有阻碍作用，实验表明水通过碳纳米管的渗透率比经典模型预测的要大1000倍。然而，紧密堆积的碳纳米管的均质通道很难大量合成。支撑石墨烯薄片显示出更多的大规模合成前景，但目前是通过高度氧化的分层过程从石墨中提取的，该过程提供了大量的残余氧原子，使无摩擦传输失效。该项目将利用自下而上的非氧化方法来创建具有可控通道的支撑石墨烯膜，该膜具有针对氧、氮、氢、氦和水等小分子的尺寸选择性传输而优化的可控通道。该项目将使用分子间隔物作为支撑剂来合成原始未氧化的平行石墨烯薄片之间的可控纳米通道。将开发强大的化学方法来精确地制造具有2-8埃的亚纳米间隙的纳米通道，以提供尺寸选择性。候选间隔基分子包括对位取代苯衍生物，通过[2+2]环加成反应接枝的官能团，以及非共价吸附的平面和非平面芳香烃。分离的双层通道和多层叠层膜都将被制造出来。孤立的通道将提供结构和性能的基本表面科学测量，而多层膜将使传输的宏观测量能够验证无摩擦、超高渗透传输的理论预测。微结构表征数据，结合传输测量，将指导日益有效的膜材料的设计。研究生和本科生都将为这个项目进行实验室研究，努力瞄准代表性不足的群体。这项研究将为针对高中生的互动课程提供信息，同时向教师传播培训视频。

项目成果

Invariance of Water Permeance through Size-Differentiated Graphene Oxide Laminates

• DOI: 10.1021/acsnano.8b02015
• 发表时间: 2018-08-01
• 期刊: ACS NANO
• 影响因子: 17.1
• 作者: Saraswat, Vivek;Jacobberger, Robert M.;Arnold, Michael S.
• 通讯作者: Arnold, Michael S.