Decorated Traditional Zeolites with Subunits of Metal–Organic Frameworks for CH₄/N₂ Separation

Abstract

Metal-organic frameworks (MOF) materials are promising materials for gas separation, but their application still faces various challenges.As trategy is nowr eported for introducing subunits of MOFs into traditional zeolite frameworks to obtain applicable adsorbents with advantages of both zeolites and MOFs.The subunits of ZIFs were introduced into zeolite Yand zeolite ZSM-5 for CH 4 /N 2 separation. Both the molecular simulation and experimental results validated that the IAST CH 4 /N 2 selectivity of the resulting samples greatly improved (above 8, at 100 kPaa nd 25 8 8C) with the incorporation of ZIF subunits into zeolites structure,a nd the selectivities were obviously higher than that of zeolites and even better than that of ZIFs.This strategy not only gave rise to an efficient adsorbent for CH 4 /N 2 separation but also provided ideas for design of other adsorption and separation materials.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Controllable Synthesis of Metal-Organic Frameworks and Their Hierarchical Assemblies

“…Very recently, Liu and coworkers introduced MOF subunits or fragments into traditional zeolite frameworks including zeolite Y and ZSM-5 to enhance the CH 4 /N 2 separation selectivity of traditional zeolite adsorbents. 141 They found that the CH 4 /N 2 selectivity of the composites according to the ideal adsorbed solution theory improved significantly, much higher than the individual zeolite or ZIF components.…”

Ultramicroporous carbon granules with narrow pore size distribution for efficient CH4 separation from coal‐bed gases

“…The development of high‐performance adsorbents for separation of CH 4 /N 2 mixtures is particularly challenging, owing to the similar kinetic diameters (CH 4 : 3.80 Å and N 2 : 3.64 Å) and comparable polarizability (CH 4 : 26.0 × 10 −25 cm 3 and N 2 : 17.6 × 10 −25 cm 3 ) of the two compounds 13 . Thus, numerous studies have attempted to improve CH 4 /N 2 separation performances using various adsorbents, for example, porous carbons, 14 zeolites, 15 and metal–organic frameworks (MOFs) 16 . For instance, Ma and coworkers prepared a novel MOF—ATC‐Cu (H 2 ATC = 1,3,5,7‐adamantane tetracarboxylic acid)—as a new type of CH 4 nano‐trap that exhibited a benchmark CH 4 capacity of 2.9 mmol/g and CH 4 /N 2 selectivity (50/50, v/v) of 9.7 at 298 K and 1 bar 17 .…”

Facile synthesis of ultramicroporous carbon adsorbents with ultra‐high CH4 uptake by in situ ionic activation

“…One potential strategy for accomplishing this goal involves the selective adsorption of dilute CH 4 from a stream of CH 4 /N 2 by porous materials, which would be both economically and operationally feasible, as well as highly energy efficient. In this regard, many adsorptive materials, including metal–organic frameworks (MOFs), zeolites, and carbon‐based adsorbents, have been examined for the separation of CH 4 /N 2 7‐10 . Specifically, MOFs comprise a new generation of porous materials that have recently demonstrated excellent CH 4 adsorption properties; for example, MOF‐177, 11 M 3 (HCOO) 6 (M = Co, Ni), 12 Co 3 (C 4 O 4 ) 2 (OH) 2 , 13 all exhibit high uptake values for CH 4 , or high CH 4 /N 2 selectivity.…”

“…In this regard, many adsorptive materials, including metal-organic frameworks (MOFs), zeolites, and carbon-based adsorbents, have been examined for the separation of CH 4 /N 2 . [7][8][9][10] Specifically, MOFs comprise a new generation of porous materials that have recently demonstrated excellent CH 4 adsorption properties; for example, MOF-177, 11 M 3 (HCOO) 6 (M = Co, Ni), 12 Co 3 (C 4 O 4 ) 2 (OH) 2 , 13 all exhibit high uptake values for CH 4 , or high CH 4 /N 2 selectivity. However, these materials still face significant challenges before they can be considered for real applications, such as demonstrating long-term stability under exposure to these gas streams, decreasing the cost of manufacturing these materials, and synthesizing a material that exhibits both high CH 4 /N 2 selectivity and high CH 4 capacity.…”