A TIFSIX pillared MOF with unprecedented zsd topology for efficient separation of acetylene from quaternary mixtures

A new TIFSIX anion pillared metal organic framework with abundant electronegative sites for efficient C2H2/CO2separation

“…Our group has long been interested in the design of new anion hybrid MOFs for light hydrocarbon separation. [26][27][28][29][30][31][32][33][34][35] Particularly, two anions are preferred, i.e. a closo-dodecaborate [B 12 H 12 ] 2− anion [26][27][28][29][30][31][32][33] and a TIFSIX [TiF 6 ] 2− anion.…”

Extraordinary Separation of Acetylene-Containing Mixtures in a Honeycomb Calcium-Based MOF with Multiple Active Sites

“…The uptake of C 2 H 2 at 273/298 K under 100 kPa is 99.3/64.6 cm 3 g –1 , which far surpasses the values of C 2 H 4 (60.3/29.5 cm 3 g –1 ), C 2 H 6 (53.0/29.2 cm 3 g –1 ), CO 2 (43.0/23.7 cm 3 g –1 ), and CH 4 (16.4/9.6 cm 3 g –1 ) in the same conditions. At 298 K and 100 kPa, although the adsorption capacity of C 2 H 2 in 1a is lower than the adsorption values of ZNU-4 (85.1 cm 3 g –1 ) and NbU-1 (81.5 cm 3 g –1 ), it is comparable to MUF-17 (67.4 cm 3 g –1 ) and far exceeds BSF-1 (52.6 cm 3 g –1 ) and SNNU-17 (37.9 cm 3 g –1 ) . In addition, the affinity between 1a and the adsorbates is also different, as revealed by the curve slopes in the low-pressure region. , The isotherm slope of C 2 H 2 is much steeper than those of C 2 H 4 , C 2 H 6 , CH 4 , and CO 2 , manifesting a stronger interaction of 1a to C 2 H 2 .…”

“…The value of 9.1 cm 3 g –1 is equivalent to 74.0% of the uptake obtained by the static adsorption curve (12.3 cm 3 g –1 of C 2 H 2 at 5 kPa). The corresponding dynamic separation factor is 3.5, which is not good as some top-performing MOF materials ZNU-4 (5.4), JCM-1 (4.4), and ZJU-74a (4.3) but exceeds those of some existing MOFs, such as SNNU-45 (2.9), HOF-3a (2.0), FJU-22a (1.9), and ZJNU-13 (1.8) …”

“…The value of 9.1 cm 3 g −1 is equivalent to 74.0% of the uptake obtained by the static adsorption curve (12.3 cm 3 g −1 of C 2 H 2 at 5 kPa). The corresponding dynamic separation factor is 3.5, which is not good as some topperforming MOF materials ZNU-4 (5.4), 16 JCM-1 (4.4), 51 and ZJU-74a (4.3) 52 but exceeds those of some existing MOFs, such as SNNU-45 (2.9), 31 HOF-3a (2.0), 53 FJU-22a (1.9), 41 and ZJNU-13 (1.8). 54 In addition, C 2 H 2 can also be separated from more complex equimolar ternary mixtures of C 2 H 2 −C 2 H 4 −C 2 H 6 and C 2 H 2 − C 2 H 4 −CO 2 by a single dynamic breakthrough operation (argon as carrier gas accounts for 85%).…”

“…The emerging metal–organic frameworks (MOFs) based on physical adsorption are promising sorbents for gas separation because of their potent predictability and tunability on pore shape/size and functionality. − The typical features provide prospective design of target materials with desirable properties for specific molecular recognition. , In this respect, a large number of MOFs were reported to selectively capture C 2 H 2 from CO 2 or other C 1 /C 2 light hydrocarbons. − However, for the two important separations of C 2 H 2 from CO 2 or C 2 H 4 , only a few MOFs were found to be effective in the actual breakthrough experiments due to their low selectivity stemming from comparable molecular sizes and physical properties (Table S1). − In particular, the separations of C 2 H 2 from more challenging ternary gas mixtures to model complex C 2 H 2 -rich industrial gas mixtures have rarely been reported. , To achieve this goal, it is still desirable to explore new MOFs with excellent C 2 H 2 selectivity and high adsorption capacity over other gases.…”