Abstract
Silicalite is an important nanoporous material that finds applications in several industries, including gas separation and catalysis. While the sorption, structure, and dynamics of several molecules confined in the pores of silicalite have been reported, most of these studies have been restricted to low pressures. Here we report a comparative study of sorption, structure, and dynamics of CO2 and ethane in silicalite at high pressures (up to 100 bar) using a combination of Monte Carlo (MC) and molecular dynamics (MD) simulations. The behavior of the two fluids is studied in terms of the simulated sorption isotherms, the positional and orientational distribution of sorbed molecules in silicalite, and their translational diffusion, vibrational spectra, and rotational motion. Both CO2 and ethane are found to exhibit orientational ordering in silicalite pores; however, at high pressures, while CO2 prefers to reside in the channel intersections, ethane molecules reside mostly in the sinusoidal channels. While CO2 exhibits a higher self-diffusion coefficient than ethane at low pressures, at high pressures, it becomes slower than ethane. Both CO2 and ethane exhibit rotational motion at two time scales. At both time scales, the rotational motion of ethane is faster.
Original language | English |
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Article number | 24010099 |
Journal | Molecules |
Volume | 24 |
Issue number | 1 |
DOIs | |
State | Published - 2019 |
Externally published | Yes |
Funding
Funding: This research was funded by the U.S. Department of Basic Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences, Geosciences Program, grant number DESC000687, and A. P. Sloan Foundation funded Deep Carbon Observatory. This research was funded by the U.S. Department of Basic Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences, Geosciences Program, grant number DESC000687, and A. P. Sloan Foundation funded Deep Carbon Observatory. Acknowledgments: We would like to acknowledge STFC’s Daresbury Laboratory for providing the packages DL-Monte and DL-Poly, which were used in this work. We would also like to acknowledge computational support from the Deep Carbon Observatory cluster, hosted by Rensselaer Polytechnic Institute (Peter Fox and Patrick West).
Keywords
- CO
- Ethane
- Molecular dynamics
- Monte Carlo
- Silicalite
- Sorption