A hydrothermally stable, zirconium-based metal-organic framework called UiO-66-Zr has been studied for its ability to separate SF6 from SF6/N-2 mixtures. The ideal adsorbed solution theory (IAST)-predicted selectivities based on single-component isotherms and the dynamic breakthrough calculations for mixture conditions demonstrate that UiO-66-Zr can effectively separate SF6/N-2 mixtures. Remarkably, UiO-66-Zr exhibits the highest SF6/N-2 selectivity values ever reported. In comparison with zeolite-13X, which is a benchmark adsorbent, UiO-66-Zr clearly shows enhanced separation performance, especially for the diluted SF6 concentration. Moreover, UiO-66-Zr maintains its adsorption capacity even after one month of storage under ambient conditions. UiO-66-Zr may be considered as a promising adsorbent for SF6/N-2 separations. (C) 2015 Elsevier B.V. All rights reserved.