Optimized CO2 capture of the zeolitic imidazolate framework ZIF‑8 modified by solvent-assisted ligand exchange
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Date
2021
Authors
Abraha, Yuel W.
Tsai, Chih-Wei
Niemantsverdriet, J. W. Hans
Langner, Ernst H. G.
Journal Title
Journal ISSN
Volume Title
Publisher
American Chemical Society
Abstract
Zeolitic imidazolate frameworks, like ZIF-8 and related structures, have shown great potential for the capture of carbon dioxide. Modifying their structure by exchanging part of the constituent organic ligands is a proven method for enhancing the capacity to absorb CO2. In this work, we performed solvent-assisted ligand exchange (SALE) on nanosized ZIF-8 (nZIF-8) with a series of functionalized imidazole derivatives (exchange percentages, after 24 h): 2-bromoimidazole (19%), 2-chloroimidazole (29%), 2-trifluoromethylbenzimidazole (4%), 2-mercaptobenzimidazole (4%), and 2-nitroimidazole (54%). The sodalite topology and porosity of nZIF-8 were maintained with all SALE modifications. Low-pressure CO2 adsorption of nZIF-8 (38.5 cm3 g–1) at STP was appreciably enhanced with all mixed-linker SALE products. Using halogenated (−Cl, −Br, and −CF3) imidazole derivatives in a 24 h SALE treatment resulted in increases between 11 and 22% in CO2 adsorption, while the thiol (−SH)- and nitro (−NO2)-functionalized SALE products led to 32 and 100% increases in CO2 uptakes, respectively. These CO2 uptakes were further optimized by varying the SALE treatment time. The SHbIm- and NO2Im-exchanged SALE products of nZIF-8 show 87 and 98 cm3 g–1 of CO2 uptakes after 60 and 120 h of SALE, respectively. These are record high CO2 adsorptions for all reported ZIF derivatives at low-pressure conditions.
Description
Keywords
Zeolitic imidazolate framework, Chemistry, ZIF-8, Carbon dioxide, Greenhouse gas
Citation
Abraha, Y.W., Tsai, C., Niemantsverdriet, J.W.H., & Langner, E.H.G. (2021). Optimized CO2 capture of the zeolitic imidazolate framework ZIF‑8 modified by solvent-assisted ligand exchange. ACS Omega, 6, 21850-21860. https://doi.org/10.1021/acsomega.1c01130