(479a) Functionalization of Metal Organic Frameworks for Enhanced Stability Under Humid Environment for CO2 Capture Applications

A need for efficient carbon dioxide capture and storage (CCS) technology heightened in the last few decades due to alarming increase in CO₂ atmospheric concentration which was ascribed to be a possible cause for global climate change. Decarbonization of flue gas from the post-combustion process via adsorption onto porous solid media such as metal organic frameworks (MOFs) have shown their effectiveness among a variety of carbon mitigation technologies.^1,2 Unique structural characteristics of MOFs including extremely large surface area coupled with nanopores, a number of MOFs have demonstrated competitive CO₂ adsorption capacity under the low-pressure conditions simulating the CO₂ concentration in the flue gases (10-15%). However, most of the previous CO₂ capture performance evaluations for MOFs have been carried out using dry CO₂, which is not realistic considering the practical composition of the flue gas. For instance, Mg/DOBDC, the MOF that presents the highest CO₂ adsorption capacity among other MOFs, exhibited significant decrease in its CO₂ capacity under the presence of humidity, possibly due to its strong hydrophilicity.³

Here we present the functionalization of MOF frameworks as a facile route to enhance the adsorbent stability and the CO₂ affinity under practical conditions involving humid CO₂ capture. Specifically, the surface of the nanopores in Mg/DOBDC is decorated by the functional groups such as ethylene diamine to prevent the direct contact of water molecules to the open metal sites of the MOF framework, using the post-synthetic functionalization techniques reported in our previous work.⁴ The material stability of the functionalized Mg/DOBDC is evaluated via accelerated steam treatment experiments, while being tested by various characterization techniques including surface area and pore size analyzer, XRD, TGA, IR, etc. The CO₂ capture performance of the functionalized Mg/DOBDC upon exposure to humid environment will be also presented.

            (1)      Choi, S.; Drese, J. H.; Jones, C. W. ChemSusChem 2009, 2, 796.

            (2)      Sumida, K.; Rogow, D. L.; Mason, J. A.; McDonald, T. M.; Bloch, E. D.; Herm, Z. R.; Bae, T. H.; Long, J. R. Chemical Reviews 2012, 112, 724.

            (3)      Kizzie, A. C.; Wong-Foy, A. G.; Matzger, A. J. Langmuir : the ACS journal of surfaces and colloids 2011, 27, 6368.

            (4)      Choi, S.; Watanabe, T.; Bae, T.-H.; Sholl, D. S.; Jones, C. W. The Journal of Physical Chemistry Letters 2012, 3, 1136.