Two kinds of membranes using imidazole groups and Zn ions respectively as CO2 carriers are designed to investigate different facilitated transport behaviors and the concomitant separation properties. Poly(N-vinylimidazole)@CNT (PVI@CNT) and Zn-poly(N-vinylimidazole)@CNT (Zn-PVI@CNT) nanoparticles are synthesized via precipitation polymerization then incorporated into polyimide to prepare hybrid membranes. PVI@CNT filled membrane shows CO2 facilitated transport behavior and distinctly enhanced CO2 separation property with a maximum CO2 permeability increment of 90% at humidified state, which is attributed to the nucleophilic addition reaction between imidazole group and CO2. Zn-PVI@CNT filled membrane shows CO2 facilitated transport behavior and distinctly enhanced CO2 separation property with a maximum CO2 permeability increment of 93% at dry state, which is attributed to the pi complexation reaction between Zn ion and CO2. The different facilitated transport behaviors of these two membranes are further analyzed for the rational design and intensified separation properties of membrane materials. (C) 2016 Elsevier B.V. All rights reserved.