A Bifunctional Microporous In(III)-MOF for SF6 Separation and Reverse Adsorption of C2H4/C2H6

The adsorption-separation process is important to the purification of gas components due to its high efficiency and low energy consumption, but the selection of adsorbents is quite challenging. Herein, a microporous In(III)-MOF (HBU-25) was synthesized by the reaction of L (L: 1,1,2,2-Tetra(4-carboxylphenyl)ethylene) ligand and In(NO3)3·4H2O. It shows a large Brunauer–Emmett–Teller (BET) specific surface area (788.4 m2 g–1) and a suitable pore environment, exhibiting excellent gas separation performance. The adsorption capacity of SF6 is 47.9 cm3 g–1 at ambient conditions, which is higher than that of CO2 (39.6 cm3 g–1) and N2 (3.4 cm3 g–1). The IAST selectivity of SF6/N2 achieves 97.2. More interestingly, it also can preferentially adsorb C2H6 (67.9 cm3 g–1) instead of C2H4 (62.3 cm3 g–1), and the IAST selectivity of C2H6/C2H4 (10:90) is calculated as 1.97. Furthermore, breakthrough experiments prove that HBU-25 can separate SF6 from the SF6/CO2/N2 mixture and achieve reverse adsorption of C2H4/C2H6.