For most of porous materials such as zeolites and metal-organic frameworks, CO2 adsorption capacity is significantly degraded in the presence of water vapor. To identify materials that exhibit enhanced CO2 adsorption capacity under wet conditions, in silico screening of hundreds of all silica zeolites was performed using Monte Carlo simulations. Through the screening process, it is shown that CO2 adsorption capacity can be either increased or decreased depending on the CO2/H2O binding site separations and characteristics of CO2-H2O interaction energies. As expected, CO2 adsorption capacity is largely degraded as its binding sites overlap with the water sites. On the contrary, CO2 adsorption performance is enhanced when CO2/H2O binding sites are clearly separated. In addition, we show that CO2 adsorption enhancement in several zeolite materials is observed even when the separation distances between the binding sites for CO2 and H2O are quite close (i.e., less than 3 angstrom). From the analysis, we can observe that the enhancement of CO2 adsorption in these zeolite structures mainly comes from the favorable long-range Coulomb interaction between CO2 and water molecules.

Understanding the mechanisms of CO2 adsorption enhancement/degradation in all silica zeolites under wet conditions

253rd National Meeting (2017)

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