Ni-Based Anionic Metal–Organic Framework for Efficient Separation of C2H2 from C2H4 and CO2 Mixtures

Abstract

Selective separation of acetylene (C₂H₂) from carbon dioxide (CO₂) and ethylene (C₂H₄) remains a significant challenge in the field of gas separation. Non-thermally driven separation technology based on metal–organic frameworks (MOFs) offers an efficient and environmentally friendly approach. Herein, a Ni-based anionic MOF (iMOF-1A) was employed for gas separation for the first time. The differential recognition of various gas molecules is enhanced by suitable pore sizes, accessible aromatic rings, and cations outside the framework. Experimental results demonstrate that iMOF-1A exhibits exceptional uptake ratios for C₂H₂/CO₂ (2.27) and C₂H₂/C₂H₄ (1.48), which surpass those of most previously reported MOF materials. Furthermore, the ideal adsorbed solution theory (IAST) selectivity calculations display a promising theoretical separation performance, which is supported by molecular simulations. Breakthrough experiments further validate that iMOF-1A not only effectively separates C₂H₂/CO₂ and C₂H₂/C₂H₄ mixtures but also exhibits excellent separation performance and humidity stability for C₂H₂/C₂H₄/CO₂ ternary mixtures.