Using lantern Zn/Co-ZIF nanoparticles to provide channels for CO2 permeation through PEO-based MMMs

Abstract

To reduce the diffusion resistance of CO2 and enhance its permeability in mixed matrix membranes (MMMs), lantern Zn/Co-ZIF nanoparticles were loaded in-situ into semi-interpenetrating cross-linked poly(ethylene oxide) (XLPEO) membranes to provide efficient channels for CO2 permeability. TEM and SEM results showed that the Zn/Co-ZIF nanoparticles (diameter 490–550 nm) treated at 145 °C possessed a lantern structure with hollow cores (diameter 380–450 nm) and thin shells (thickness 20–85 nm). XRD and BET results indicated that the nanocrystal structure and porosity of the Zn/Co-ZIF remained intact after etching at 145 °C. Peaks shifts in the infrared spectra confirmed that the Zn/Co-ZIF nanoparticles were well integrated with the XLPEO membrane through hydrogen bonds. Therefore, doping 15 wt% lantern Zn/Co-ZIF nanoparticles into the membrane dramatically increased CO2 permeability by 72% to 761.9 ± 3.0 barrers, while the CO2/N2 selectivity was above the upper bound established by Robeson in 2008.