二维材料气体分离膜的设计制备、结构调控及传递机理研究

In recent 5 years, atom-thick two-dimensional materials show great potential in development of high-performance separation membranes. Two-dimensional-material-membranes (2DMMs) have achieved numerous progresses in liquid separation, while only a few in gas separation, mainly due to the weakness in constructing and controlling the sub-nanometer transport channels, yet understanding the transport mechanism. Therefore, this proposal presents the fundamental study of rational preparation, structure controlling and transport mechanism of 2DMMs. Typical 2D materials are rationally synthesized as the building blocks, and new preparation methods are proposed to fabricate 2DMMs with various structures and functional groups. External force fields are introduced to regulate the nanosheet assembly for building sub-nano pore structures, meanwhile molecular modifications are applied to finely tune the pore size and functionalities, so as to obtain high-performance 2DMs with fast and selective transport channels for gas separation. A theoretical design and preparation framework is proposed for the 2DMs. Gas sorption and permeation measurements, atomic-scale characterizations such as positron annihilation and small-angel X-ray scattering techniques, as well as molecular simulations for theoretical calculation are combined to obtain the characteristics of 2DMs pore structure and gas transport, thereby establishing the gas transport model for 2DMs. It’s believed that the implementation of this project will provide useful insights and techniques for developing new 2DMs for gas separation.

近五年来，原子层厚度的二维材料在高性能分离膜领域显现出巨大潜力与应用价值。二维材料膜在液体分离的研究取得了突出进展，然而在气体分离仍处于摸索阶段，缺乏亚纳米尺寸孔道的构筑与调控策略，分离机理模糊不清。为此，本项目拟开展二维材料气体分离膜的设计制备、结构调控及传递机理的基础研究。项目拟从可控制备二维材料作为构筑单元出发，研究不同结构与基团性质的二维材料膜的制备新方法；引入外部力场诱导二维材料组装构筑有序的亚纳米孔道结构，通过分子修饰精密调控孔道尺寸与基团性质，发展具有快速选择性传递通道的高性能二维材料气体分离膜，初步建立二维材料气体分离膜的设计与制备理论框架。结合气体分子吸附、渗透行为，正电子湮灭、小角X射线散射等原子尺度表征，及分子模拟理论计算，抽提二维材料膜的孔道结构与气体传质特性参数，构建二维材料气体分离膜的传质理论模型。项目实施将为二维材料气体分离膜的发展提供理论与技术参考。

近年来多种二维材料，如石墨烯类材料、过渡金属碳化物（MXene）、金属有机框架化合物（MOF）纳米片，被认为是新一代高性能膜材料。目前，以石墨烯为代表的二维材料膜研究集中在水处理领域，然而二维材料膜在气体分离的研究却相对甚少。本项目针对发展用于气体分离的二维材料膜所面临的瓶颈问题，以合成尺寸与结构完整的氧化石墨烯与MOF纳米片为典型二维构筑单元，设计制备不同结构的二维材料膜，系统研究二维材料及其膜的设计与制备，二维材料膜的亚纳米孔道构筑方法与结构调控，并深入研究其气体分离机理。.课题组成员四年内积极探索了二维材料，包括石墨烯、MXene、MOF等膜的制备方法。研究了分离膜微结构和层间通道的精密调控方法，揭示了二维材料的成膜机理及膜内传质和分离机理，二维材料膜的构筑及其在气体分离方面的应用。在研期间项目负责人在AIChE Journal, Nature Materials, Nature Communications, Angewandte Chemie International Edition, Advanced Functional Materials, Journal of Membrane Science等国际顶级期刊和化工、材料主流期刊上发表SCI收录论文39篇。申请中国发明专利5项，其中2项已获授权。在国内外重要学术会议上作邀请报告19次。本项目在设计思路、制备方法、传质机理及其在气体分离中应用等方面取得的研究结果，为二维材料膜的制备与应用提供了理论与技术指导，同时为二维材料在其它相关膜领域的研究开辟了新思路。