【Frontiers in HaiChuan Chemical Technology】Tianjin University achieves large-scale continuous production of “MOF-based pressure-resistant carbon dioxide separation hybrid matrix composite membranes”

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Recently, a team led by Professor Wang Zhi from the School of Chemical Engineering at Tianjin University developed a cationic polymer brush-metal-organic framework (MOF) material based on the \"pre-occupation–post-activation\" (POPA) strategy, enabling the large-scale continuous \"roll-to-roll\" production of \"MOF-based pressure-resistant carbon dioxide separation hybrid matrix membranes\" with a width of up to 1 meter. 　　The efficient separation of carbon dioxide is a key aspect in reducing emissions. Membrane-based carbon capture technology offers advantages such as low energy consumption, no solvent evaporation-related pollution, the ability to integrate the equipment in modular form, and a small footprint. In recent years, researchers at home and abroad have developed various high-performance hybrid matrix membranes, but the areas of these membranes produced are far from sufficient to meet the requirements for industrial deployment. The key bottleneck restricting its large-scale continuous manufacturing is the problem of \"non-equilibrium processing-induced filler instability\" – that is, a filler dispersion system that is stable under mild laboratory conditions becomes highly unstable during the rapid, non-equilibrium dynamic processing involved in industrial coating, thereby leading to filler agglomeration and multi-scale interfacial defects. 　　To address this challenge, the team proposed a \"pre-occupy then activate\" strategy, developing a cationic polymer brush MOF material that combines static dispersion with dynamic processing stability, and achieving original breakthroughs in three aspects. First is to innovate the concept of material design. Traditional research has been limited to static dispersion under laboratory conditions; this team proposed that fillers intended for large-scale membrane production must possess both static and dynamic stability, upgrading the design criterion from merely \"stability under static conditions\" to \"stability under dynamic conditions\". 　　Second is to develop tunnel protection strategies. To address the issue of polymer-modified pores becoming clogged, the team adopted a \"pre-occupation–post-activation\" strategy: first, protonated amino groups were used to occupy the pores, thereby guiding the grafting on the outer surface of the polymer ； Subsequent “post-activation” through deprotonation restores the activity of the amino groups and keeps the pores open, achieving a strategy of “blocking first and then unblocking,” thereby forming a polymer brush layer while ensuring efficient transport of carbon dioxide. 　　Third, establish a dual stabilization mechanism. The highly positively charged framework and surface polymer brushes work together to exert electrostatic and steric hindrance effects, ensuring stable dispersion in a static state ； The freely extendable polymer brushes form an interfacial interlocking structure with the polymer matrix through dense hydrogen bonds; during the rapid evaporation of the solvent, they adaptively resist the \"aggregation-induced force,\" thereby fundamentally solving the problem of dynamic instability. 　　On this basis, Wang Zhi’s team collaborated with enterprises to carry out technical verification on an industrial scale, and achieved large-scale, continuous, and stable production of \"MOF-based pressure-resistant carbon dioxide separation hybrid matrix membranes\" with a width of up to 1 meter, using an industrially designed \"roll-to-roll\" coating production line of their own design. The membrane produced exhibits excellent performance in applications such as natural gas decarbonization and post-combustion carbon capture. Through systematic sampling and multiple batch tests, it has demonstrated good scalability and uniformity. 　　In the future, this technology is expected to play a key role in areas such as industrial flue gas treatment, natural gas decarbonization, and syngas purification, providing technical support to reduce costs and improve efficiency in the carbon capture, utilization, and storage value chain.