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(NO 3 ) 3 ·4H 2 O. It shows a large Brunauer–Emmett–Teller (BET) specific surface area (788.4 m 2 g –1 ) and a suitable pore environment, exhibiting excellent gas separation performance. The adsorption capacity of SF 6 is 47.9 cm 3 g –1 at ambient conditions, which is higher than that of CO 2 (39.6 cm 3 g –1 ) and N 2 (3.4 cm 3 g –1 ). The IAST selectivity of SF 6 /N 2 achieves 97.2. More interestingly, it also can preferentially adsorb C 2 H 6 (67.9 cm 3 g –1 ) instead of C 2 H 4 (62.3 cm 3 g –1 ), and the IAST selectivity of C 2 H 6 /C 2 H 4 (10:90) is calculated as 1.97. Furthermore, breakthrough experiments prove that HBU-25 can separate SF 6 from the SF 6 /CO 2 /N 2 mixture and achieve reverse adsorption of C 2 H 4 /C 2 H 6 .