Molecular dynamics simulations of metal-organic frameworks as membranes for gas mixtures separation

We use molecular dynamics simulations to analyze the dynamic behavior of the CO2/N2 and CO2/CH4 gas mixtures through IRMOF-1 and Cu-BTC metal-organic frameworks-based membranes. Two approaches are considered to simulate the membrane system: permeation at constant pressure gradient and permeation at variable pressure gradient. The results show that both materials would work similarly to separate CO2/N2 and that Cu-BTC is the most acceptable to separate CO2/CH4 gas mixtures. The roles of diffusion and adsorption are clearly elucidated from the simulations. These simulation results also demonstrate how metal-organic framework properties influence the separation ability of the membrane and help to understand the dynamic mechanism of the process at a molecular level thus providing orientations that may guide experimental work.

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► Permselectivities obtained from metal-organic framework membrane simulations.
► Simulated time-lag clarifies diffusion and adsorption roles in membrane separations.
► Separation efficiencies calculated based on final compositions in the membrane.