Poly (ether-block-amide) (Pebax) based mixed matrix membranes (MMMs) were prepared by using size-tunable ZIF-8 nanoparticles as fillers. ZIF-8 nanoparticles with sizes of 40, 60, 90 and 110 nm (ZIF-8-40, ZIF-8-60, ZIF-8-90 and ZIF-8-110) were synthesized in microemulsion by controlling the ratio of Zn²⁺ to Hmim (1:16, 1:8, 1:5, 1:2). And they were distributed uniformly in Pebax matrix without obvious agglomerations and defects at the loading of 0–20 wt.%, which was confirmed by field-emission scanning electron microscopy (FE-SEM). The incorporation of ZIF-8 resulted in a significant improvement in CO₂ permeability and the CO₂/N₂ selectivity increased with the BET surface area of ZIF-8 increasing. The enhanced permeability is attributed to an improvement in the free volume of the polymer induced by larger sized ZIF-8, while the increased selectivity results from the high specific surface area of large sized ZIF-8, which can provide more active sites for CO₂ capture and great mass transfer resistance for N₂. At 5 wt.% loading of ZIF-8-90, the MMM presents the best separation performance with CO₂ permeability of 99.7 Barrer and CO₂/N₂ selectivity of 59.6, both of which are increased by about 25% by comparison to the pure Pebax membrane. The present study provides an effective way to obtain size-controlled ZIF-8 fillers and high separation performances of Pebax based MMMs.

通过使用尺寸可调的ZIF-8纳米粒子作为填料，制备了基于聚（醚嵌段酰胺）（Pebax）的混合基质膜（MMM）。通过控制Zn的比例在微乳液中合成尺寸为40、60、90和110 nm的ZIF-8纳米颗粒（ZIF-8-40，ZIF-8-60，ZIF-8-90和ZIF-8-110）²⁺到Hmim（1：16、1：8、1：5、1：2）。场发射扫描电子显微镜（FE-SEM）证实，它们在Pebax基质中均匀分布，在0-20 wt。％的负载下没有明显的团聚和缺陷。ZIF-8的加入显着改善了CO _2的渗透性和CO ₂ / N ₂选择性随着ZIF-8的BET表面积的增加而增加。更大的渗透性归因于较大尺寸的ZIF-8引起的聚合物自由体积的改善，而选择性增加的原因是较大尺寸的ZIF-8的高比表面积可为CO ₂提供更多的活性位点对N _2的俘获和较大的传质阻力。在5 wt。％的ZIF-8-90负载下，MMM表现出最佳的分离性能，CO ₂渗透率为99.7 Barrer和CO ₂ / N ₂选择性为59.6，与纯Pebax膜相比，两者均提高了约25％。本研究提供了一种获得尺寸控制的ZIF-8填料和基于Pebax的MMM的高分离性能的有效方法。