Fluorocarbon Separation in a Thermally Robust Zirconium Carboxylate Metal-Organic Framework.

Fluorocarbons have important applications in industry, but are environmentally unfriendly, and can cause ozone depletion and contribute to the global warming with long atmospheric lifetimes and high global warming potential. In this work, the metal-organic framework UiO-66(Zr) is demonstrated to have excellent performance characteristics to separate fluorocarbon mixtures at room temperature. Adsorption isotherm measurements of UiO-66(Zr) display high fluorocarbon sorption uptakes of 5.0 mmol g-1 for R22 (CHClF2 ), 4.6 mmol g-1 for R125 (CHF2 CF3 ), and 2.9 mmol g-1 for R32 (CH2 F2 ) at 298 K and 1 bar. Breakthrough data obtained for binary (R22/R32 and R32/R125) and ternary (R32/R125/R134a) mixtures reveal high selectivities and capacities of UiO-66(Zr) for the separation and recycling of these fluorocarbon mixtures. Furthermore, the UiO-66(Zr) saturated with R22 and R125 can be regenerated at temperatures as low as 120 °C with excellent desorption-adsorption cycling stabilities.