Fabrication of zeolitic imidazolate frameworks based mixed matrix membranes and mass transfer properties of C₄H₆ and N₂ in membrane separation

1,3-Butadiene (BD) is a petrochemical-based volatile organic compound, extensively used for the manufacture of synthetic rubber. There is no method reported for its recovery from nitrogen mixture. Herein, for the first time, BD is efficiently recovered by gas separation through facile and novel mixed-metal ZIF-8 based mixed matrix membranes (MMMs). Addition of Ni-ZIF-8 nanoparticles in PDMS matrix, significantly improved the penetrant-membrane interactions and the solution-diffusion properties of BD. Positron annihilation lifetime spectroscopy analysis showed that the well dispersion of Ni-ZIF-8 in PDMS enhanced the free volume of membrane and created efficient continuous paths for BD diffusion. Then, 15 wt% Ni-ZIF-8 MMM exhibited the BD permeance of 323 GPU and the BD/N₂ ideal selectivity of 19.5, which were 60 and 81% higher than pure PDMS membrane, respectively. The simultaneous enhancement of BD permeance and BD/N₂ ideal selectivity indicated that Ni-ZIF-8 was an effective filler applied in MMMs for efficient BD recovery.