Creating and Optimizing Porous Metal Organic Frameworks for the Capture of Carbon Dioxide from Flue Gas Mixtures

Carbon dioxide is a greenhouse identified as a major contributor to global warming. In order to decrease the amount of carbon dioxide emitted to the atmosphere, and slow down global warming, two issues must be addressed. First, carbon dioxide must be taken from the air in a low cost and energy efficient manner. Second, the captured carbon dioxide must be converted into useful materials or fuel. This project focuses on research addressing the first aspect, specifically, CO2 capture from flue gas mixtures by adsorption-based separation methods. Such methods have the advantages of being applicable over a broad range of temperature and pressure, and having low energy penalty. However, to make such a process practical, it is essential to develop cost effective adsorbents with high selectivity and capacity, especially at relatively low pressures (e.g. ~0.1-0.15 atm, the partial pressure of CO2 in flue gases).

Recent research shows that porous metal organic framework (MOF) materials are emerging as a promising family of such adsorbents. This project centers on the design, synthesis and optimization of MOFs for selective adsorption of CO2 over N2 in flue gas mixtures. Solvothermal and solution growth methods are employed to synthesize and grow crystals of M2(hfipbb)2(ted) [M = Co, Zn; H2hfipbb = 4,4'-(hexafluoroisopropyl idene)bis(benzoic acid); ted = triethylenediamine], and Cu3(TDPAT)·(H2O)3 [H6TDPAT = 2,4,6-tris(3,5-dicarboxylphenylamino)-1,3,5-triazine]. Structures and thermal properties are analyzed using X-ray diffraction techniques and thermogravimetric analysis. This study demonstrates that enhanced interactions between CO2 (adsorbate) and frameworks (adsorbent) may be achieved by modifying the MOF structures and composition.