Design of a Tunable, High-performance Mixed Matrix Membrane Platform for Gas Separations

Membrane technology offers substantial economic and environmental benefits for energy-intensive chemical separations. Chabazite-type zeolite, possessing a 3-D channel system with molecular-sieving windows, can be an ideal membrane material, but conditions to synthesize zeolite-only membranes limit optimization strategies. Guided by advanced quantum chemistry calculations on inner-pore molecular interactions, zeolite properties are tailored for different separations and optimized particles incorporated in polyimide at very high loadings. A membrane platform is thus created that largely outperforms state-of-the-art membranes for a broad variety of industry-relevant applications, that is, carbon capture, natural gas/biogas purification, hydrocarbon, helium and hydrogen recovery. Accurate size-sieving of gas molecules is realized together with rational determination of optimal gas-zeolite interactions. Crucial for industrial applications, these well-tuned membranes displayed excellent non-aging properties, high flexibility and higher mixed-gas selectivities than ideal-gas selectivities. Moreover, they performed even better at low CO₂-partial pressure in CO₂-removal and can be made humidity-insensitive.