2022 Annual Meeting

(645f) Impact of Metal-Organic Framework Characteristics on Electrostatic Interactions for GCMC-Simulated Adsorption

Authors

Walton, K., Georgia Institute of Technology
Metal-organic frameworks (MOFs) have received a great deal of attention in recent years as showing significant potential towards a wide variety of applications due to their tunable nature. One such application is that of mixture adsorption, a complicated issue with many factors involved.1 As mixture adsorption is both challenging and time-consuming to experimentally measure, predictive methods such as the Ideal Adsorbed Solution Theory (IAST) and molecular simulations have been widely used as an easier alternative to measure mixture adsorption.2 Grand Canonical Monte Carlo (GCMC) simulations can directly compute adsorbed loadings from a gas mixture onto a given MOF, but these results are dependent upon simulation parameters.3 One component of these simulation parameters are the electrostatic interactions between the adsorbent and adsorbate which can be either included or excluded in the simulations. Though typically included, the comparison of adsorbate loadings when including or excluding these electrostatic interactions can provide insight into their role in adsorptive MOF applications as well as the impacts of MOF characteristics on these interactions.

Unary CO2 adsorption was simulated using GCMC with frameworks exhibiting differing characteristics such as varied pore size, inclusion of functionalized ligands, and open-metal sites. Two sets of simulations were completed, one including electrostatic interactions between the adsorbent and adsorbate and the other excluding them, allowing investigation into framework characteristics’ effects on the electrostatic interactions. Binary adsorption with mixtures of CO2 and C1-C4 hydrocarbons was also simulated, both with and without electrostatic interactions, to observe the impact of electrostatics on these non-charged C1-C4 species in mixtures.

References:

  1. Li, J. R.; Kuppler, R. J.; Zhou, H. C., Selective gas adsorption and separation in metal-organic frameworks. Chem. Soc. Rev. 2009, 38 (5), 1477-1504.
  2. Myers, A. L.; Prausnitz, J. M., Thermodynamics of mixed-gas adsorption. Aiche J. 1965, 11 (1), 121-127.
  3. Dubbeldam, D.; Torres-Knoop, A.; Walton, K. S., On the inner workings of Monte Carlo codes. Molecular Simulation 2013, 39 (14-15), 1253-1292.