Evaluating the viability of ethylenediamine-functionalized Mg-MOF-74 in direct air capture : The challenges of stability and slow adsorption rate
Abstract
Carbon removal technologies, such as direct air capture (DAC), hold great potential in mitigating anthropogenic CO2 emissions. Amine-tethered metal-organic frameworks (MOFs) that capture CO2 selectively via chemisorption have been highlighted as frontrunners for CO2 removal technologies. To this end, ethylenediamine (ED) was employed to decorate the metal sites of Mg-MOF-74, and both bare and amine-modified frameworks were thoroughly characterized and studied for DAC using an automated fixed-bed sorption device. The material exhibited a promising CO2 capacity of up to 1.8 mmol/g from 400 ppmv CO2 in humid conditions, although the amount of adsorbed H2O was several times higher. The highest adsorption capacities were measured at 25–35 °C, while decreased capacity was observed at 12 °C due to slower adsorption rate. In dry cyclic adsorption-desorption tests, the cyclic CO2 capacity reduced slightly in 18 cycles. However, at 2 vol% humidity, the capacity dropped rapidly over successive cycles, revealing poor hydrolytic stability. Preliminary coating experiments were conducted on stainless steel plates and cordierite monoliths, suggesting that reasonably even coating layers could be achieved on these substrates with relatively simple coating techniques. High water adsorption, slow adsorption rate at low temperatures, and the rapid cyclic capacity decrease in humid conditions may limit the application of the studied adsorbent for DAC. The vital aspects of the real application of MOFs in DAC, such as adsorption kinetics and stability in humid conditions, are rarely explored in detail in the literature, and these results indicate that these aspects warrant extensive study for the development of practically applicable DAC adsorbents.
Main Authors
Format
Articles
Research article
Published
2024
Series
Subjects
Publication in research information system
Publisher
Elsevier
The permanent address of the publication
https://urn.fi/URN:NBN:fi:jyu-202402222077Use this for linking
Review status
Peer reviewed
ISSN
2213-3437
DOI
https://doi.org/10.1016/j.jece.2024.112193
Language
English
Published in
Journal of Environmental Chemical Engineering
Citation
- Mahajan, S., Elfving, J., & Lahtinen, M. (2024). Evaluating the viability of ethylenediamine-functionalized Mg-MOF-74 in direct air capture : The challenges of stability and slow adsorption rate. Journal of Environmental Chemical Engineering, 12(2), Article 112193. https://doi.org/10.1016/j.jece.2024.112193
Funder(s)
Research Council of Finland
Funding program(s)
Academy Programme, AoF
Akatemiaohjelma, SA

Additional information about funding
This study was conducted as a part of the DAC2.0 project funded by the Academy of Finland under grant numbers 329312 and 329314 and the University of Jyväskylä.
Copyright© 2024 The Authors. Published by Elsevier Ltd.