MOF基混合基质气体分离膜界面作用调控研究进展

Research review in regulating interfacial interaction on MOF-based m ixed matrix membranes for gas separation

混合基质膜结合了无机填充材料和聚合物组分的双重优势,被认为是一种可同时增加渗透性和选择性的新型方法,有望解决传统聚合物膜的Trade-off效应。混合基质膜的气体分离性能主要依赖无机填充材料的分子筛分性质和高分子本身的化学结构,因此适当选择无机填充材料对于制备高性能的混合基质膜十分重要。金属有机骨架(MOF)作为一种新型多孔填料,具有比表面积大、密度小、孔隙率高和孔尺寸可调等优点,因此在气体吸附分离和气体储存等领域应用广泛,为新型混合基质膜带来良好的发展机遇。但混合基质膜的分离性能并不是简单地两相性能相加,在大多数情况下分离性能远低于材料模拟的预测理论值,造成这种非理想性的关键因素之一是MOF晶体和聚合物之间的界面缺陷,这可能导致界面非选择性空隙的形成、聚合物硬化和孔隙堵塞等界面问题,降低膜的分离性能。因此,实现MOF-聚合物基质间的界面作用调控以改善界面相容性是充分发挥MOF基混合基质膜气体分离潜力的关键。本工作综述了MOF基混合基质膜近五年关于不同类型界面作用调控的方法及策略,及其对气体分离性能的影响。最后,总结构建的界面作用对于混合基质膜性能的正面影响并提出当中存在的问题,为混合基质膜未来的发展提供指导,并激励研究人员采取更多的策略来解决目前的挑战。

Mixed matrix membranes(MMMs) have attracted substantial attention for gas separation,combining the advantages of organic polymers and inorganic fillers,which are expected to solve the Trade-off effect.Metal organic frameworks(MOF),as a kind of innovative filler,provided promising development opportunities for MMMs,thanks to high surface area and porosity,adjustable pores,and low density,etc.These unique physical and chemical properties promoted the application in gas adsorption,separation,and storage.MOF is regarded as good compatibility with the polymer matrix because the organic linkers in MOF are more similar to the organic chain of the polymer compared with traditional inorganic materials(molecular sieve or metal oxide,etc.).Gas separation performance is improved by incorporating MOF into the polymer matrix,which is expected to balance the Trade-off effect.However,the separation performance of MMMs is not simply the sum of the two phases and is far below the predicted theoretical value by the material simulation in most cases.One of the key reasons for these non-ideal morphologies resulting from poor interfacial compatibility,including the non-selective interfacial voids,polymer rigidified,and pore blockage,which reduce the separation performance of MMMs.Therefore,good interfacial compatibility plays a key role in MMMs.Constructing effective interface interactions is a feasible strategy to improve interface compatibility.Thus,in this review,a comprehensive overview of the main technical challenges in developing MOFbased MMMs and a detailed description of the interface issues are provided.And constructing different interface interactions,including hydrogen bonds,covalent bonds,coordination bonds and others,has been expounded through various methods and strategies in the last five years.Finally,it aims to summarize the positive effects on the properties of MMMs through effective and strong interface interactions,guiding the future development of MOF-based MMMs.