MOFs effectively capture carbon from wet flue gasS. Himmelstein | December 12, 2019
Metal-organic frameworks (MOFs) are promising solid adsorbents for the capture of carbon dioxide from flue gases. These nanoporous structures efficiently separate CO2 from nitrogen but lose their efficiency under real flue gas conditions, as the water present competes with the gas for the same adsorption sites and causes the materials to lose their selectivity.
A data mining approach was applied by an international research team to the identification of MOF materials and structures possessing adsorbaphores: strong but hydrophobic binding sites that maintain CO2 selectivity in the presence of water. Two water-stable MOFs containing the most hydrophobic adsorbaphore were synthesized after evaluation of a computational screening library of over 300,000 MOFs. The adsorbaphore contained two aromatic cores, or binding sites — one for water and one for CO2.
The performance of the newly minted MOFs proved comparable or superior to activated carbon and other commercially available CO2 removal materials. The presence of two aromatic cores effectively eliminated competition between moisture in wet flue gas and the target gas for binding sites.
Researchers from Oregon State University, École Polytechnique Fédérale de Lausanne (Switzerland), Heriot-Watt University (Scotland), University of Ottawa (Canada), University of California Berkeley and Universidad de Granada (Spain) participated in this study.