Water-Stable Metal−Organic Framework with a Tuned Pore Microenvironment for Selective Acetylene Separation

Abstract Due to the highly similar molecular dimensions, polarizability, and physicochemical properties among C2H2, CO2, C2H6, and C2H4, these gas molecules always exhibit analogous adsorption behaviors in conventional porous adsorbents. Therefore, the precise and high-efficient separation of C2H2 from multi-component light hydrocarbon mixtures remains a formidable challenge in practical industrial separation processes. In this work, we have synthesized a metal−organic framework denoted ZJNU-412, which possesses one-dimensional channels functionalized with uncoordinated O atoms and aromatic rings. These functional groups serve as high-affinity recognition sites toward C2H2. At 298 K and 1 bar, the C2H2 uptake capacity of ZJNU-412 reaches 49.6 cm3 g−1, markedly exceeding those of CO2 (21.8 cm3 g−1), C2H6 (21.6 cm3 g−1), and C2H4 (21.0 cm3 g−1). Ideal adsorbed solution theory (IAST) calculations revealed that the considerable separation selectivity for equimolar C2H2/CO2, C2H2/C2H6, and C2H2/C2H4 mixtures is 10.8, 10.0, and 11.7, respectively. Fixed-bed breakthrough experiments verified that ZJNU-412 can efficiently isolate C2H2 from binary C2H2/CO2, C2H2/C2H6, and C2H2/C2H4 mixtures as well as a complex quaternary C2H2/CO2/C2H6/C2H4 system, accompanied by outstanding cycling stability. Impressively, this material retained its outstanding separation performance even under 50% relative humidity. Collectively, these results reveal that ZJNU-412 exhibits great potential for broad industrial applications in acetylene separation.