Study On PIM-1/ZIF-8 Modified Membrane And Its O₂/N₂ Separation Performance

In the field of O₂/N₂ separation technology,membrane separation technology has many advantages,such as low cost,energy saving and environment friendly.Among many separation membrane materials,MOFs?Metal Organic Frameworks?mixed matrix membranes have both good mechanical properties of polymer materials and excellent gas separation performance of MOFs,showing a good application prospect.However,the compatibility between MOFs particles and polymer matrix is poor in the traditional preparation method of MOFs mixed matrix membrane,and the agglomeration of MOFs is easy to occur under the condition of high MOFs loadings,forming non-selective interface gap,resulting in poor gas separation performance and poor mechanical properties of the membrane.In order to solve the above problems,,ZIF-8 with appropriate pore diameter and size and PIM-1 polymer with high O₂/N₂separation performance were selected in this paper,PIM-1/ZIF-8 composite membranes and ZIF-8/PIM-1 mixed matrix membranes were prepared by in-situ growth method,and the physicochemical properties and O₂/N₂separation performance of the membranes were measured:?1?ZIF-8 nanoparticles were introduced onto the surface of PIM-1 membrane through in-situ growth method,and a series PIM-1/ZIF-8 composite membranes were prepared by increasing the growth cycles of ZIF-8 nanoparticles.The obtained PIM-1/ZIF-8 composite membranes had excellent thermal stabilities,and effectively improved the interface defects between the polymer and the filler,ZIF-8 nanoparticles showed good compatibility with PIM-1 membrane.The permeability coefficients of O₂and N₂ of PIM-1/ZIF-8-7 composite membrane was 1287 and 351 barrer respectively,the selectivity of O₂/N₂ was 3.7,and the O₂/N₂ separation performance exceeded the Robeson upper bound line.?2?ZIF-8 nanoparticles were introduced into the network structures and internal channels of the PIM-1 polymer through in-situ growth method,and ZIF-8/PIM-1 mixed matrix membranes were prepared by increasing the growth cycles of ZIF-8nanoparticles.The obtained ZIF-8/PIM-1 mixed matrix membranes had excellent thermal stabilities and good mechanical properties.ZIF-8 nanoparticles were grown in the network structures and pore walls of PIM-1 without agglomeration,and ZIF-8nanoparticles had good compatibility with the PIM-1 matrix.The permeability coefficients of O₂ and N₂ of ZIF-8_12h/PIM-1 mixed matrix membrane was 2742 and 834barrer respectively,and the selectivity of O₂/N₂ was 3.3.The O₂/N₂ separation performance exceeded the Robeson upper bound line.