Computational Guided Structural Design for Optimized Pore Size and Shape Metal-Organic Framework Enabling One-Step CH₄ and C₃H₈ Purification From CH₄/C₂H₆/C₃H₈ Ternary Gas Mixture

Current natural gas upgrading strategies primarily focus on CH₄ recovery, treating C₂H₆ and C₃H₈ merely as impurities, which results in resource wastage. In this work, an advanced industrial operation, simultaneous separation of both pure CH₄ and C₃H₈ from CH₄/C₂H₆/C₃H₈ ternary gas mixture was realized. Herein, based on semi-empirical computational screening, the desired pore features were identified as an ideal nonpolar aromatic surface, a cage-like geometry, and a suitable pore size. A new material Ni-pza-ina was directionally designed and synthesized. Sorption and separation experiments demonstrated that Ni-pza-ina served the industrial operation well with superior separation performance compared to its parent analogue Ni-bdc-ina and many other materials. Molecular simulations elucidated that the shape/size matching and distinct affinity differences between C₂H₆ and C₃H₈ are the governing factors, which are responsible for the successful separation of CH₄ (6.05 mmol g⁻¹, purity > 99.5%) and C₃H₈ (0.90 mmol g⁻¹, purity > 99.5%) from CH₄/C₂H₆/C₃H₈ 85:10:5 (v/v/v) ternary in the breakthrough experiment. Finally, the industrial viability of Ni-pza-ina was demonstrated through an industrial two-bed PSA process simulation, which achieved high recoveries of CH₄ (69.17%) and C₃H₈ (92.69%) in a single cycle, underscoring its promise for realistic industrial application.