Integrating Self-Partitioned Pore Space and Amine Functionality into an Aromatic-Rich Coordination Framework with Ph Stability for Effective Purification of C₂ Hydrocarbons

Abstract

A great demand for high-purity C 2 hydrocarbons calls for the development of chemically stable porous materials for the effective isolation of C 2 hydrocarbons from CH 4 and CO 2 . However, such separations are challenged by their similar physiochemical parameters and have not been systematically studied to date. In this work, we reported a cadmium-based rod-packing coordination framework compound ZJNU-140 of a new 5,6,7-c topology built up from a custom-designed tricarboxylate ligand. The metal–organic framework (MOF) features an aromatic-abundant pore surface, uncoordinated amine functionality, and self-partitioned pore space of suitable size. These structural characteristics act synergistically to provide the MOF with both selective recognition ability and the confinement effect toward C 2 hydrocarbons. As a result, the MOF displays promising potential for adsorptive separation of C 2 –CH 4 and C 2 –CO 2 mixtures. The IAST-predicted C 2 /CH 4 and C 2 /CO 2 adsorption selectivities, respectively, fall in the ranges of 7.3–10.2 and 2.1–2.9 at 298 K and 109 kPa. The real separation performance was also confirmed by dynamic breakthrough experiments. In addition, the MOF can maintain skeleton intactness in aqueous solutions with a wide pH range of 3–11, as confirmed by powder X-ray diffraction (PXRD) and isotherm measurements, showing no loss of framework integrity and porosity. The excellent hydrostability, considerable uptake capacity, impressive adsorption selectivity, and mild regeneration make ZJNU-140 a promising adsorbent material applied for the separation and purification of C 2 hydrocarbons.