Energy-saving separation of ethane/ethene (C2H6/C2H4) mixtures is of great importance and challenge. In this work, we reported an iron-based metal-organic framework PCN-250 as a C2H6-selective adsorbent for efficient C2H4 purification from C2H6/C2H4 mixtures. Adsorption isotherms of C2H6 and C2H4 were measured and their adsorption capacities were 5.21 and 4.22 mmol/g at 298 K and 100 kPa, respectively. The adsorption selectivities of C2H6/C2H4 mixtures (1:15 and 1:1, v/v) were in the range of 1.9-4.0 on the basis of ideal adsorbed solution theory (IAST). Meanwhile, its separation performance was also corroborated by the breakthrough experiments, indicating the potential of C2H4 purification from C2H6/C2H4 mixtures, particularly for trapping C2H6 from typical cracked gas mixtures (C2H6/C2H4, 1:15). Compared with C2H4-selective adsorbents through pi-complexation interactions, the isosteric adsorption heat of C2H6 on PCN-250 was much lower and thus could require less energy for desorption. Meanwhile, configurational-biased grand canonical Monte Carlo (CB-GCMC) method was employed to well simulate its adsorption behaviors in PCN-250. Simulation results showed that the favorable adsorption sites of C2H6 and C2H4 were distributed at four corners near benzene rings and around the N atoms of PCN-250. Both the pore effect and the van der Waals (vdW) adsorption energy governed the separation of C2H6 over C2H4 for PCN-250, especially at low pressures. Providing that PCN-250 is used as a C2H6-selective adsorbent for purifying C2H4 from C2H6/C2H4 mixtures, this high-performance material can hold great potential for trapping C2H6 from C2H6/C2H4 mixtures. (C) 2017 Elsevier Ltd. All rights reserved.