冰晶模板法构筑高渗透性GO/MOF有机溶剂纳滤膜及其分离机理研究

Organic Solvent Nanofiltration (OSN) is a widely investigated membrane separation technology, which is environmentally friend and features high efficacy in the separation of mixed solvents in pharmaceutical and chemical engineering. OSN membranes with controllable mass transfer, high performance and stability represents major needs for this area of research. Graphene Oxide (GO) has been extensively studied as a novel membrane material owing to its unique confined-transfer ability as well as outstanding separation potential. Nevertheless, the nano-channel of GO membranes is susceptible to external pressure, resulting in declined permeability with time. This project proposes a strategy to prepare high performance GO/Metal-Organic Framework (GO/MOF) composite OSN membranes through the combination of ice-templating and in-situ growth of MOF, which allows the extension of interlayer spacing of GO sheets and defect fixing. Effects of membrane structure and operation condition were systematically investigated to figure out the optimal OSN membranes. Chemical modification was further applied to enhance the solvents permeability and the solutes rejection of. In this project, a synergistic design of ice-templating, in-situ growth and surface modification is proposed. It provides not only a pathway to fabricate high performance GO composite OSN membranes with controllable mass transfer channels, but also shed light on the OSN separation mechanism, which is of important value from scientific and practical perspectives.

有机溶剂纳滤（OSN）是一种广泛应用于医药、化工领域混合溶剂分离纯化的膜技术，具有绿色高效的优点。开发具有可控传质、高性能、稳定OSN膜是该领域亟需解决关键问题。氧化石墨烯膜（GO）因其独特限域促进传质能力和优异的分离潜能被广泛用于分离膜研究，但其缺陷孔通道耐压密差，渗透性易衰减。针对这一问题，本项目提出冰晶模板法，结合金属有机框架材料（MOF）在GO膜内原位生长，增加GO片层间距和支撑微观缺陷孔并创造传质通道，制备结构优化的GO/MOF杂化膜，获得高渗透性OSN性能。研究膜结构和操作条件对有机分子分离性能的影响，选择性能较优的杂化膜，通过化学修饰进一步强化有机分子传质，提高OSN膜分离性能。本项目提出了冰晶模板法-原位杂化技术-膜表面改性手段协同的设计思路，建立了制备传质可控、性能稳定GO杂化膜的新途径，研究了有机溶剂高性能膜分离机制，具有重要的理论与实际价值。

氧化石墨烯膜（GO）因其独特限域促进传质能力和优异的分离潜能被广泛用于分离膜研究，但其缺陷孔通道耐压密差，渗透性易衰减。针对这一问题，以GO为筑膜纳米基元，自下而上进行组装成膜，采用低场核磁（LF-NMR）与X射线衍射（XRD）联用，识别和分析GO膜内有序和无序堆叠结构。提出“冰晶模板-选择杂化”和“凝胶限域-交联刚化”的策略，增加GO片层间距和支撑微观缺陷孔并创造传质通道，构建了耐高压稳定的纳米和亚纳米结构联通的快速溶剂传递通道的GO基纳滤膜；根据Onsager模型提出的空间体积排斥效应，建立了GO分散液临界浓度模型，推演了GO膜内两种堆叠极限结构，并通过模型指导，进行GO膜可控组装实现CO2的高效分离。研究膜结构和操作条件膜分离性能的影响规律，阐明了高通量的传输机制。本项目研获得的GO膜结构强化路径以及可控组装构建的理论模型，为构筑高性能GO膜提供了指导，具有重要的科学意义以及应用前景。