UiO‐66‐NH2 particle size effects on gas separation performance of cellulose acetate composite membranes

Abstract UiO‐66‐NH 2 (Zr‐based metal organic framework) is integrated into cellulose acetate (CA) to fabricate mixed matrix membranes (MMMs) through solvent‐casting approach. To regulate the interfacial compatibility and suppress the non‐selective voids, UiO‐66‐NH 2 with different particle sizes are investigated. The introduction of UiO‐66‐NH 2 provides additional pathways for gas molecules and renders the membrane with high CO 2 affinity, substantially augmenting the separation efficiency of UiO‐66‐NH 2 @CA composite membrane. By optimizing the particle size of UiO‐66‐NH 2 , the non‐selective voids and the particle agglomeration can be effectively restricted. The optimum separation performance is obtained by U‐100@CA membrane (UiO‐66‐NH 2 : 200 nm in size), exhibiting a CO 2 permeability of 168.8 Barrer with CO 2 /N 2 and CO 2 /CH 4 ideal selectivities of 40.2 and 51.3, respectively. The separation mechanism is ascribed to the presence of sufficient amine groups, the high CO 2 solubility of CA matrix, and superior inorganic–organic interfacial property.