Finely Tuned Framework Isomers for Highly Efficient C2H2 and CO2 Separation

Obtaining the optimal physiadsorbents based on the same starting materials is one of the crucial technologies that can address the increasing problem of energy-consuming separation. Herein, a group of porous coordination isomers (NTU-51 to NTU-54) with topologies of sql, dia, nbo, and kgm has been newly designed and prepared from a 4-c square node (paddlewheel cluster) and a 2-c linker (isophthalic acid derivative). Pure gas measurements revealed that they have a varied ability for selective C2H2 capture from C2H2/CO2 mixtures, originating from the fine arrangement of functional sites within these isomers as well as size-exclusive effects. Further dynamic breakthrough experiments exhibited good C2H2/CO2 (1/1, v/v) separation performance of the two isomers (NTU-53 and NTU-54) in both dry and humid gas phases (R.H. = 45%). More interestingly, stability tests and long-term measurements demonstrated a high potential of them to be used under realistic conditions.