Adsorption Site Selective Occupation Strategy within a Metal–Organic Framework for Highly Efficient Sieving Acetylene from Carbon Dioxide

Abstract

The separation of acetylene and carbon dioxide is an essential but challenging process owing to the similar molecular sizes and physical properties of the two gas molecules. Notably, these molecules usually exhibit different orientations in the pore channel. We report an adsorption site selective occupation strategy by taking advantage of differences in orientation to sieve the C2H2 from CO2 in a judiciously designed amine‐functionalized metal–organic framework, termed CPL‐1‐NH2. In this material, the incorporation of amino groups not only occupies the adsorption sites of CO2 molecules and shields the interaction of uncoordinated oxygen atom and CO2 molecules resulting in a negligible adsorption amount and a decrease in enthalpy of adsorption but also strengthened the binding affinity toward C2H2 molecules. This material thus shows an extremely high amount of C2H2 at low pressure and a remarkably high C2H2/CO2 IAST selectivity (119) at 1 bar and 298 K.

Robust metal–organic framework with abundant large electronegative sites for removal of CO2 from a ternary C2H2/C2H4/CO2 mixture

“…The breakthrough intervals between C 2 H 2 and CO 2 are 18.1 min g −1 at 298 K, 24.1 min g −1 at 283 K, and 27.2 min g −1 at 273 K, respectively, illustrating efficient C 2 H 2 /CO 2 separ- ation. The breakthrough time between C 2 H 2 and CO 2 for JXNU-14 is similar to those of prominent MOFs of CPL-1 (14 min g −1 ), 50 FJU-90a (22 min g −1 ), 51 SNNU-150(Al) (20.8 min g −1 ), 52 NKMOF-1-Ni (21 min g −1 ), 53 and UTSA-300 (12 min g −1 ), 54 but lower than those of leading MOFs of SNNU-45 (79 min g −1 ), 55 JXNU-12(F) (70 min g −1 ), 56 SIFSIX-Cu-TPA (69 min g −1 ), 28 and JXNU-11(Fe 2 Ni) (55 min g −1 ) 57 under similar conditions. As seen from the breakthrough curves (Fig.…”

Fine pore engineering in a series of isoreticular metal-organic frameworks for efficient C2H2/CO2 separation

“…Furthermore, the C 2 H 2 productivity of SIFSIX-dps-Cu calculated from the breakthrough curve is 2.48 mmol g −1 , which outperforms those of CPL-1-NH 2 (1.38 mmol g −1 ) 41 , and is comparable to SIFSIX-3-Ni (2.5 mmol g −1 ) 44 . And the C 2 H 2 productivity of GeFSIX-dps-Cu and NbOFFIVE-dps-Cu was calculated to be 2.36 and 0.83 mmol g −1 , respectively, which are significantly superior to that of UTSA-300a (0.77 mmol g −1 ) 13 .…”

“…30 , the calculated equimolar C 2 H 2 /CO 2 selectivity of NbOFFIVE-dps-Cu, GeFSIX-dps-Cu, and SIFSIX-dps-Cu at 298 K and 1.0 bar are 9, 172, and 1787, respectively. In particular, the selectivity of SIFSIX-dps-Cu is higher than that of UTSA-300a (743) and much higher than other benchmark MOFs (Supplementary Table 6 ), such as CPL-1-NH 2 (119) 41 , ATC-Cu (53.6) 9 , TIFSIX-2-Cu-i (6.5) 44 , UTSA-74a (9) 45 , and UTSA-222a (2) 46 . Compared with those of adsorbents with high C 2 H 2 adsorption capacities such as SNNU-45 47 , FJU-90a 48 , UPC-200(Al) 49 , and FJU-6-TATB 50 (Fig.…”

“…2a ). The high C 2 H 2 uptake of SIFSIX-dps-Cu (4.57 mmol g −1 ) outperforms many benchmark MOFs, including CPL-1-NH 2 (1.84 mmol g −1 ) 41 , NTU-65 (3.36 mmol g −1 ) 34 , and JNU-1 (2.1 mmol g −1 ) 5 , see Supplementary Table 6 . The sorption behaviors of these dynamic MOFs are similar to those in relevant literature 39 , 42 .…”

A copper-based metal–organic framework with a suitable pore environment for effective ethylene purification

“…Considering that introducing functional groups can be an effective approach to construct novel MOFs and this is expected to modify host-guest interactions, [34][35][36] we here synthesized an amino-functionalized ligand H 4 L-CH 2 :5′,5′′′′-methylenebis(2′amino-[1,1′:3′,1″-terphenyl]-4,4″-dicarboxylic acid) (Fig. 1a).…”