基于高分子/石墨烯双层结构的反选择性膜构筑与性能研究

Reverse-selective membrane (with larger molecules permeating preferentially and smaller molecules being intercepted) has been one of the research focuses in membrane field due to its remarkable advantages in energy-saving. The commonly utilized polymeric membranes for reverse-selective separation exhibit the problems of poor continuity and broad size distribution of mass transfer channels, thus largely restricting the further improvement of membrane separation performance. To address this issue, this project is proposed to construct high-performance reverse-selective membrane based on polymer/graphene bilayer structure. First, graphene membrane with continuous and uniform nanochannels is constructed and the structure manipulation methods are explored. The mass transfer behavior of permeating molecules in graphene nanochannels is investigated via synergistic manipulation of the chemical structure and physical structure of nanochannels, so that to achieve the intensification of reverse-selective mass transfer process in nanochannels. On the basis of as-constructed graphene membrane, nanoscale polymeric layer is incorporated on membrane surface to construct membrane with polymer-graphene bilayer structure. The nanochannel structure and membrane surface structure are synergistically tailored to investigate the relationships between membrane structures and confined mass transfer process in membrane, and achieve the simultaneous improvement of solution and diffusion processes in membrane. High-efficiency reverse-selective separation is realized employing alcohol/water mixture as a model system. Hopefully, the achievement of this project could offer a reference for the design and preparation of high-performance reverse-selective membrane materials.

反选择性膜（大尺寸分子优先透过，小尺寸分子被截留）由于在节能降耗等方面的显著优势已成为膜领域的研究热点。目前反选择性分离常用的高分子膜材料存在通道连续性差、尺寸分布宽等共性问题，很大程度上限制了膜应用性能的提升。为此，本项目提出基于高分子/石墨烯双层结构构筑高性能反选择性膜的新思路。拟首先构筑具有连续均一纳米通道的石墨烯膜，探索通道结构的调控方法，并基于通道化学结构与物理结构的同步调控研究渗透分子在限域通道内的传质行为，实现通道内反选择性传质过程的强化；在所构筑石墨烯膜的基础上，向膜表面引入纳米级高分子层，构筑高分子/石墨烯双层结构膜，同步调控膜内纳米通道结构及表面高分子结构，以研究膜结构与膜内限域传质过程的构效关系，实现渗透分子溶解及扩散过程的协同强化；以醇水混合溶液为代表物系，实现高效的反选择性分离。期望通过本项目的开展，为高性能反选择性膜材料的设计制备提供参考。

针对特定的分离体系及应用场合，采用反选择性膜可实现有效的节能降耗，因此反选择性膜的研究已成为膜领域的研究热点之一。目前反选择性分离常用的高分子膜材料存在通道连续性差、尺寸分布宽等共性问题，很大程度上限制了膜应用性能的提升。本项目以高性能反选择性分离膜的设计与制备为目标，基于石墨烯等材料的结构调控，在膜内构筑高效的反选择性传质通道，突破了目前高分子膜的性能瓶颈，实现了膜通量与选择性的同步提升。同时，研究了通道化学结构与物理结构的同步调控方法，协同强化了渗透分子在膜内的溶解和扩散过程，获得了反选择性纳米通道内的限域传质规律；以醇水分离（优先透醇）作为代表性的反选择性分离物系，揭示了不同渗透分子在纳米通道内的限域传质行为及其构效关系。通过本项目的实施，在Advanced Functional Materials、Journal of Membrane Science、AIChE Journal等期刊上发表SCI论文10篇，申请中国发明专利4项（其中授权1项）。课题成员积极开展国际合作与交流活动，在国内外学术会议作报告8人次，3名成员赴国外高校进行交流学习，培养博士生5名，硕士生4名。