"High-performance mixed matrix membranes with very-high ZIF-8 loading for efficient CO2 capture"

Abstract

Addressing the challenges of climate change and global warming, membrane separation processes are considered as innovative industrial solutions. Among different membrane materials, mixed matrix membranes are very promising for CO₂ capture. In this work, a segmented poly(urea-imide) with high poly(ethylene oxide) content (70 % wt) was selected as a new rubbery polymer matrix and was doped with the metal organic framework ZIF-8. The new polymer matrix and the optimization of the “priming” method enabled to obtain very high ZIF-8 loadings up to 70 % vol. Various physicochemical methods were used to study the influence of filler/polymer interactions on the membrane's morphology. The CO₂ and N₂ permeation properties were evaluated by time-lag measurements for both pure gases under standard conditions for CO₂ post-combustion capture (2 bar and 35 °C). Very promising membrane performances were achieved for the highest ZIF-8 loading (70 % vol) with a strong increase of the CO₂ permeability P_CO2 = 471 Barrer (x 8.5 compared to the pristine polymer) and a relatively high ideal selectivity α_CO2/N2 = 30.2. The modeling of the MMM's performances was successfully achieved with Maxwell model up to high ZIF-8 content (60 % vol).