In silico screening and design strategies of ethane-selective metal-organic frameworks for ethane/ethylene separation

C2H6/C(2)H(4)separation is one of the most crucial processes in the chemical industry and currently practiced by energy-intensive distillation technology. As an alternative, adsorption-based separation is considered as technically feasible and economically viable, and there has been considerable interest to develop advanced adsorbents for C2H6/C(2)H(4)separation. In this study, we computationally screen a large set (12020) of metal-organic frameworks (MOFs) to identify top-performing candidates for selective adsorption of C(2)H(6)over C2H4. Quantitative relationships are established between the adsorption performance metrics (C(2)H(6)working capacity and C2H6/C(2)H(4)selectivity) and the structural descriptors (pore size, surface area, and porosity), as well as isosteric heat. We identify 16 top-performing MOFs with C2H6/C(2)H(4)selectivity >= 2.16 and C(2)H(6)working capacity >= 0.54 mol/kg, which are superior to a benchmarked MOF (ZJU-120a). It is revealed that pore geometry (both size and shape) are the key factors governing C2H6-selective adsorption. From topological analysis, the most common topologies are found. Finally, six design strategies are proposed: regulating topology, catenating framework, adding aromatic ring, pillar-layering framework, substituting metal node, and imposing flexibility. Each strategy is elaborated with examples for boosting separation performance. These strategies offer bottom-up guidelines for the rational design of new MOFs towards high-performance C2H6/C(2)H(4)separation.