Pore-Space Partition through an Embedding Metal-Carboxylate Chain-Induced Topology Upgrade Strategy for the Separation of Acetylene/Ethylene

Abstract

Ethylene (C2H4) is one of the most significant substances in the petrochemical industry; however, the capture of acetylene (C2H2) in about 1% from C2H2/C2H4 mixtures is a difficult task because of the similarity of their physical properties. With the aggravation of the energy crisis, using metal–organic framework (MOF) materials to purify C2H4 through adsorptive separation is a promising way to save energy and reduce emission. Pore-space partition (PSP) with the aim of enhancing the density of the binding sites and the strength of the host–guest interactions is an effective means to promote a solution for the challenging gas separation problems. Herein, we report a new embedding metal-carboxylate chain-induced topology upgrade strategy within a MOF to realize PSP and separation of C2H2/C2H4 mixtures. As a proof of concept, we construct a microporous MOF (NUM-12) utilizing the in situ insertion of cobalt terephthalic chains into a pretargeted ant-type framework during synthesis. Because of the attainment of an elaborately tuned aperture size and a specific pore environment through this strategy, NUM-12a (activated NUM-12) not only has a remarkable gas sorption capacity and strong interactions for C2H2 but also possesses an excellent purification performance for C2H2/C2H4 mixtures. Both experiments and simulation calculations clearly reveal that NUM-12 is a promising candidate for the separation of C2H2/C2H4, proving the feasibility of this new strategy for developing newly fashioned MOFs with adjustable structure and performance.

A linker conformation induced metal–organic framework with high stability and efficient upgrading of natural gas

“…3b). Excitingly, the loading capacity of C 3 H 8 at 298 K and 1 bar is similar to some, and outperforming other MOF materials, such as FMM-202A (6.76 mmol g −1 ), 47 and MIL-100(Fe) (6.78 mmol g −1 ), 48 and surpasses numerous famous materials, such as Cu-MOFs (5.98 mmol g −1 ), 49 Mg-MOF-74 (∼5.95 mmol g −1 ), 50 MIL-142A (5.82 mmol g −1 ), 51 and LIFM-26 (5.2 mmol g −1 ) 52 (Fig. 3c and Table S2 †).…”

Optimizing the pore space of a robust nickel–organic framework for efficient C2H2/C2H4 separation

“…3c). Obviously, under the ambient conditions, the C 2 H 2 /C 2 H 4 selectivity of UPC-22 is higher than that of most reported promising MOFs, such as MgMOF-74 (2.18), 36 FeMOF-74 (2.08), 37 BSF-1 (2.3), 38 NUM-9a (1.63), 4 NOTT-300 (2.17), 39 and NUM-12a (1.4), 40 but lower than that of some leading MOFs, such as SNNU-40 (4.5) 41 and ZJU-198 (7.2). 42 Furthermore, the C 2 H 2 /C 2 H 6 selectivity is 2.6 and 2.4 at 298 K, corresponding to the ratio of 50 : 50 (v/v) and 1 : 99 (v/v), respectively (Fig.…”

Isoreticular Contraction of Cage-like Metal–Organic Frameworks with Optimized Pore Space for Enhanced C2H2/CO2 and C2H2/C2H4 Separations

“…In light of the tunable pore size/shape/volume, − and functionable pore surface, − metal–organic frameworks (MOFs), emerging as a new class of porous solid materials, have attracted a lot of attention in the field of gas adsorption and separation. − The pore system involving pore size/shape/volume and pore space environment can be precisely regulated by substituting the organic linkers with the same symmetry or the inorganic metal nodes based on the isostructural principle and building block strategy, − which in turn endows MOFs with enormous potentials for selective gas separation via the integration of pore size/shape matching and preferential binding interactions toward specific gas molecules. − So far, tremendous endeavors have been devoted to improving the enrichment and separation performance for specific gas molecules, in which the construction of cage-like mixed-ligands MOFs without open metal sites (OMSs), featuring small pore window size, functional pore space, and appropriate pore volume, has represented one of the most effective approaches. − For instance, the pore-space-partition-based MOFs (PSP-MOFs), with cage-like cavities, have shown high performance for gas adsorption and separation, ,− attributed to the relocation of the pore system, stemming from the introduction of the second spacers, involving compartmentalized small pore, functionalized pore space, and reserved appropriate pore volume. The segmented small pore size and functionalized pore surface impart enhanced gas separation through providing dramatically increased adsorbent–adsorbate binding sites toward specific gas molecules, while the preserved appropriate pore volume bestows PSP-MOFs with high gas adsorption performance, thereby making the PSP-MOFs a prominent scaffold for gas adsorption and separation, including C 2 H 2 and CO 2 capture, , C 2 H 2 /CO 2 , − C 2 H 2 /C 2 H 4 /C 2 H 6 , and C 3 H 6 /C 3 H 8 separation. ,, Additionally, the cage-like MOFs without OMSs usually exhibit relatively low adsorption enthalpy compared with the MOFs with O...…”