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 C 2 H 2 /CH 4 and C 2 H 2 /CO 2 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 C 2 H 2 /CH 4 , CO 2 /CH 4 , and C 2 H 2 /CO 2 , the separation mechanism of C 2 H 2 /CH 4 in our ZIF-8 membrane can be attributed to a higher affinity for acetylene and molecular sieving effect, while C 2 H 2 /CO 2 separation is related to thermodynamic factors. It is worth noting that this is the first example of MOF membranes to successfully separate C 2 H 2 from CH 4 and CO 2 .