Ultrathin polyamide membrane tailored by mono-(6-ethanediamine-6-deoxy)-β-cyclodextrin for CO2 separation

The fabrication of membranes with high CO2 separation performances is an urgent need for clean energy supply and environmental remediation. In this work, the mono-(6-ethanediamine-6-deoxy)-β-cyclodextrin (MEDβCD) fillers are intentionally constructed to tailor the polyamide membranes (MEDβCD/PA) by interfacial polymerization (IP) for CO2 separation. The unique hollow cone structure of MEDβCD alleviates the vigorous IP process, generating a thinner separation layer with larger chain d-spacing. Additionally, the introduction of CO2-philic groups from MEDβCD can facilitate CO2 molecule transport. The fabricated MEDβCD/PA membrane exhibits remarkable increases in CO2 permeance, CO2/H2, CO2/N2, and CO2/CH4 selectivities, which are 39, 17, 11, and 25 times higher than those of the pure PA membrane, respectively. This work provides a straightforward route to fabricate composite membranes tailored by macrocyclic molecules with cone structures and other cavitands for gas separation.