关键词: 混合基质膜, 气体分离, 界面改性, 金属有机框架材料

Abstract:

Gas membrane separation technology is extremely common in the chemical industry. Compared with traditional gas separation technology, it has advantages such as a small footprint, low energy consumption, simple operation, energy conservation and environmental protection, and thus has a wide range of application prospects. Membrane materials, as the core of gas membrane separation technology, have been widely studied. Among them, the mixed matrix membranes (MMM) based on metal-organic frameworks (MOF) have high permeability and selectivity, making them a promising gas separation membrane material. There are various types of MOF materials with adjustable pore structure and surface modifiability. However, there are differences in properties between MOF particles and polymers, poor compatibility and uneven dispersion, leading to interface defects such as particle aggregation, polymer chain segment stiffness and particle pore blockage in MMM, which in turn affect the gas separation performance and mechanical properties of the membrane. This article summarized four methods to improve the compatibility of MOF-based MMM based on different modification principles, namely functionalization of MOF, encapsulation of MOF, modification of polymer and post-treatment of MMM. Based on the examples of researchers, the types of polymers and MOF used in the preparation of MMM, the target gas, the mechanism of modification methods and the modification objectives were explained. Comparing the permeability, selectivity and mechanical properties of MMM before and after modification, the separation effect achieved after interface modification was demonstrated. Finally, the existing modification methods were discussed and the development space for existing interface optimization methods was proposed, such as considering the characteristics of the molecules themselves, temperature and aging conditions, and using predictive models to pre-screen polymer filler combinations. In the future, it should be focused on the industrial application scenarios of MMM to increase the load capacity, maximize the advantages of porous MOF, enhance the mechanical and aging resistance of membranes, and promote the further commercial development of MMM.

Key words: mixed matrix membrane, gas separation, interface modification, metal-organic frame materials