Evidence of the kinetic-driven separation of butane isomers in UiO-66 (Zr) MOF, a combined experimental and computational study

TL;DR

This study demonstrates that UiO-66 MOF can effectively separate n-butane from isobutane based on kinetic differences, with n-butane diffusing significantly faster due to lower energy barriers, promising high selectivity for industrial separation processes.

Contribution

The paper provides combined experimental and computational evidence showing kinetic-driven separation of butane isomers in UiO-66 MOF, highlighting the molecular mobility differences responsible for separation.

Findings

n-Butane diffuses faster than isobutane in UiO-66

Diffusion barrier is 25 kJ/mol for n-butane and 50 kJ/mol for isobutane

Rate ratio of diffusion at 303 K is 1700

Abstract

UiO-66 is a well-known metal organic framework that proved to be promising for various separation applications. In this report we study the molecular mobility and transport of n-butane and isobutane through the UiO-66. We show that n-butane propagates through the material significantly faster than isobutane both in terms of energetics (diffusion barrier is 25 kJ mol-1 for n-butane and 50 kJ mol-1 for isobutane) and rate (Di(303 K)/Dn(303 K) = 1700). This result allows expecting very high kinetic driven separation selectivity of n-butane/isobutane mixture in UiO-66.