Screening MOFs for C2H2 /CO2 Mixture Separations using PSA Simulations

The focus of this communication is on separation of C 2 H 2 /CO 2 mixtures using metal-organic frameworks (MOFs) that are selective to ethyne. The desired ethyne is recoverable in the desorption cycle of pressure swing adsorption (PSA) schemes. The productivity of purified C 2 H 2 , say with purities > 95%, is highest for MOFs for which the CO 2 uptake capacities are small; the C 2 H 2 /CO 2 adsorption selectivity is usually not a good indicator of separation performance. The primary objective of the communication is suggest the use of a simplified two-step PSA scheme, with adsorption followed by counter-current desorption, for screening MOFs. The suggested methodology involves transient breakthrough simulations of adsorption and counter-desorption for ranking MOFs. The PSA scheme is used to compare the separation performance of nine different C 2 H 2 -selective MOFs. Only four MOFs are found to be capable of producing C 2 H 2 with purities > 95%: CPL-1-NH 2 , ZNU-1, Cu Ι @UiO-66-(COOH) 2 and SOFOUR-TEPE-Zn. Of these MOFs, the highest C 2 H 2 productivity is achievable with SOFOUR-TEPE-Zn.