A stable metal-organic framework with oxygen site for efficiently trapping acetylene from acetylene-containing mixtures

Highly selective separation of acetylene from various other gases (e.g., carbon dioxide and methane) is of great importance in the petrochemical industry but remains a challenge due to their similar sizes and physical properties. Herein, we reported a microporous metal -organic framework Zn4O(NTB)2 (H3NTB = 4,4 ',4 ''- nitrilotribenzoicacid acid), features oxygen binding sites explored for C2H2 capture and separation. A high C2H2 uptake of 2.62 mmol g-1 combined with excellent selectivity of C2H2/CO2 (4.8) and C2H2/CH4 (21.6) under ambient conditions (i.e., 50:50 mixture at 298 K and 1 bar) was realized. Moreover, the grand canonical Monte Carlo (GCMC) simulations and first-principles density functional theory (DFT) calculations have identified that the high C2H2 capture and selectivity ascribe to oxygen sites on the pores (C-H...O interaction). Dynamic breakthrough experiments comprehensively demonstrate that Zn4O(NTB)2 is a promising adsorbent for practical C2H2/CO2 and C2H2/CH4 separation.

Automated summary

Highly selective separation of acetylene from various other gases is challenging due to their similar sizes and physical properties. In this study, a microporous metal-organic framework Zn4O(NTB)2 with oxygen binding sites was used for C2H2 capture and separation. The framework exhibited high C2H2 uptake and excellent selectivity for C2H2/CO2 and C2H2/CH4. Dynamic breakthrough experiments confirmed its potential application in practical C2H2/CO2 and C2H2/CH4 separation.