Separations of binary mixtures of CO2/CH4 and CO2/N2 with mixed-matrix membranes containing Zn(pyrz)2(SiF6) metal-organic framework

Abstract

In this work, mixed-matrix membranes comprising Zn(pyrz)2(SiF6) (or SIFSIX-3-Zn) metal-organic framework were fabricated for potential applications in biogas upgrading and post-combustion CO2 capture. First, submicron-sized Zn(pyrz)2(SiF6) crystals that selectively adsorb and transport CO2 over CH4 and N2 were synthesized by a facile sonochemical method. Then, high-quality mixed-matrix membranes free of filler/polymer interfacial voids were succesfully fabricated by employing crosslinked polyethylene oxide as a polymer matrix. CO2/CH4 and CO2/N2 mixture gas permeation tests revealed that the separation properties of mixed-matrix membranes, especially selectivities, were significantly improved compared to those of pure polymeric membrane owing to the selective CO2 uptake and transport in Zn(pyrz)2(SiF6) crystals.