Highly efficient separation of methane from nitrogen on a squarate‐based metal‐organic framework

Abstract

Highly selective capture of methane from nitrogen is considered to be a feasible approach to improve the heating value of methane and mitigate the effects of global warming. In this work, an ultramicroporous squarate‐based metal‐organic framework (MOF), [Co3(C4O4)2(OH)2] (C4O42− = squarate), with enhanced negative oxygen binding sites was synthesized for the first time and used as adsorbent for efficient separation of methane and nitrogen. Adsorption performance of this material was evaluated by single‐component adsorption isotherms and breakthrough experiments. Furthermore, density functional theory calculation was performed to gain the deep insight into the adsorption binding sites. Compared with the other state‐of‐the‐art materials, this material exhibited the highest adsorption selectivity (8.5–12.5) of methane over nitrogen as well as the moderate volumetric uptake of methane (19.81 cm3/cm3) under ambient condition. The unprecedented selectivity and chemical stability guaranteed this MOF as a candidate adsorbent to capture CH4 from N2, especially for the unconventional natural gas upgrading. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3681–3689, 2018

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

“…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. 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 14,15 .…”

Large‐Scale Screening and Design of Metal–Organic Frameworks for CH4/N2 Separation

“…A four‐connected 3D network is generated by the connection of pyramid Zn centers coordinated with four two‐connected units with rectangular 1D channels. As shown in Figure , the geometric optimization indicates that the distances between H atom of CH 4 molecule and C−H of organic ligands are about 2.137–2.267 Å, which is within the range of vdW interaction and much shorter than the distances revealed in literature (over 3.400 Å) . C−H groups on the surface of pore can form multiple van der Waals interactions with cooperative effect to lead to strong interaction with CH 4 molecule.…”

“…For example, ZnZSM‐5‐pIM was prepared with a selectivity of 8.44 . Co 3 (C 4 O 4 ) 2 (OH) 2 exhibits a highest selectivity of 12.54 . Even though these progresses, it still needs to be further improved to meet the requirement in practical.…”

Metal-Organic Framework Encapsulated Whole-Cell Vaccines Enhance Humoral Immunity against Bacterial Infection

“…These materials are useful in catalysis, separations, sensors, and recently, as non-toxic vehicles for drug delivery. [19][20][21][22][23][24][25][26][27] We and others have described a specific type of MOF called ZIF-8, 28, 29 composed exclusively of zinc metals interconnected by methylimidazole ligands, that crystallize "biomimetically" on a variety of biomacromolecules including soluble proteins, polysaccharides, viruses, and whole cells. [30][31][32][33][34][35][36] For this study, we used CFT073, a model urosepsis strain of UPEC frequently employed in the development of new vaccines.…”