Efficient Separation of Acetylene-Containing Mixtures Using ZIF-8 Membranes

Metal-organic framework (MOF) membranes show great potential in the separation of acetylene mixtures. In this work, we have prepared ZIF-8 membranes on polyamide (PA) substrates for the highly selective separation of acetylene/methane and acetylene/carbon dioxide mixtures. The C₂H₂/CH₄ and C₂H₂/CO₂ mixtures can be successfully separated using the ZIF-8 membranes, with separation factors of 12.1 and 1.8, respectively. Based on the results of the cross-permeation tests of C₂H₂/CH₄, CO₂/CH₄, and C₂H₂/CO₂, the separation mechanism of C₂H₂/CH₄ in our ZIF-8 membrane can be attributed to a higher affinity for acetylene and molecular sieving effect, while C₂H₂/CO₂ separation is related to thermodynamic factors. It is worth noting that this is the first example of MOF membranes to successfully separate C₂H₂ from CH₄ and CO₂.