A Rigid, Stable, and Scalable Aliphatic MOF Adsorbent for Efficient C2H2/CO2 Separation with Record Acetylene Packing Density

Abstract Integrating separation parameters such as high adsorption capacity and selectivity, moderate adsorption enthalpy ( Q st ), along with industrial factors including cyclic stability, cost‐effectiveness, and scalability into a single adsorbent remains highly challenging due to inherent trade‐offs among these properties. Herein, we strategically leverage the coordination modes of aliphatic ligands to significantly enhance C 2 H 2 /CO 2 separation performance. The structure flexibility and pore metrics are finely modulated by hydroxylated aliphatic acid (DLmal). As a result, the rigid Zn‐bpy‐DLmal exhibits an exceptional C 2 H 2 adsorption capacity of 1.4 mmol g −1 at 0.01 bar, high C 2 H 2 /CO 2 selectivity (49), and moderate C 2 H 2 Q st value (38.4 kJ mol −1 ). Notably, it achieves record‐high C 2 H 2 packing densities of 347 g L −1 at 0.01 bar and 747 g L −1 at 0.5 bar. Furthermore, the scale‐up production of Zn‐bpy‐DLmal to kilogram quantities has been successfully achieved at an estimated cost of $74 per kilogram. Dynamic breakthrough experiments confirm its practical C 2 H 2 /CO 2 separation performance with excellent cyclability under high flow rates and both dry and humid conditions. Moreover, two‐bed pressure swing adsorption simulations demonstrate a high‐purity C 2 H 2 (>99%) yield of 14.64 mol with a recovery of 88.2% per cycle.