Abstract
Membrane-based gas separation processes are a technology in continuous evolution. Various types of polymer membranes have been developed, many exhibiting high CO(2) permeability and selective properties over competing gases such as N(2) and CH(4). In order to be competitive, membranes must be less-expensive, more stable, and more efficient, and their production must be scalable. One solution is to develop thin-film composites with mixed-matrix membranes (TFC_MMM) that have the potential to boost productivity while maintaining low costs. In this work, TFC_MMMs containing Matrimid mixed with 12 wt % ZIF-94 were prepared by kiss coating on a porous support. The SEM analysis showed that defect-free membranes with a 3 μm selective layer have been obtained. At 1 bar, the addition of ZIF resulted in improved the separation performance for the CO(2)/N(2) pair, with CO(2) permeance of 4 GPU and CO(2)/N(2) selectivity of 40, surpassing neat TFC-Matrimid (CO(2) permeance ≈ 3 GPU, CO(2)/N(2) selectivity ≈ 29). The use of ZIF-94 also had a stabilizing effect on the membranes against CO(2) plasticization at high pressure.