Enhanced permeability in mixed matrix membranes for CO₂ capture through the structural regulation of the amino-functionalized Co/ZIF-8 heterometallic nanoparticles

High permeable and selective membranes are expected to be a promising alternative for low cost and energy efficient CO₂ separation. However, the preparation and development of highly permeable and selective membranes are limited by the trade-off effect. Here, we prepared a stabilized high permeable and selective mixed matrix membrane based on the structural regulation of the NH₂-functionalized Co/ZIF-8 heterometallic nanoparticles (NH₂-Co/ZIF-8). The NH₂-Co/ZIF-8 can be homogeneously dispersed in the polymer via chelation of the ester group and the metal node in the methacrylate-terminated PEO and the acrylate-terminated PEO. The amphiphilic interaction between the polymer and NH₂-Co/ZIF-8 significantly increased the CO₂ solubility resulting in the boost of both CO₂ permeability and CO₂/N₂ selectivity. The best performance membrane exhibits a CO₂ permeability of 2916 Barrer and a CO₂/N₂ selectivity of 47, surpassing the Robeson's upper bond (2008) by a wide margin.