UiO-66 (Zr) MOF as a Promising Material for Butane Isomers Separation: Evidence Based on the Analysis of the Adsorbed Alkanes Mobility by 2H NMR and Molecular Dynamics Simulation

UiO-66 (Zr) is a thermally and chemically stable Zr-based metal-organic framework (MOF) that has proved to be promising for different hydrocarbon separation applications including membrane-based processes. Here, we present a combined experimental (H-2 NMR) and computational (molecular dynamics simulation) study of the molecular mobility and transport of n-butane and isobutane in the dehydroxylated UiO-66 (Zr) MOF. We show that the microscopic diffusivity D-n for n-butane is significantly higher than D-is(o) for isobutane, D-n/D-iso = 1000 at 300 K with a large difference in diffusion barriers, E-n = 25 kJ mol(-1) for n-butane and E-iso = 50 kJ mol(-1)for isobutane. High selectivity for kinetic- driven separation of the n-butane/isobutane mixture in UiO-66 (Zr)-based materials or membranes is expected based on this result.

Automated summary

UiO-66 (Zr) is a thermally and chemically stable Zr-based metal-organic framework (MOF) with promising potential for separating n-butane and isobutane, showing significantly higher diffusion rate for n-butane compared to isobutane. This difference in diffusion barriers suggests high selectivity for kinetic-driven separation of the n-butane/isobutane mixture in UiO-66 (Zr)-based materials or membranes.