Statistical Mechanical Models of Adsorption and Diffusion of Fluids in Crystalline Nanoporous Materials: Extensions to Percolation and Multicomponent Fluids

Author

Austin M. Newman, University of Tennessee - Knoxville

Date of Award

5-2004

Degree Type

Thesis

Degree Name

Master of Science

Major

Chemical Engineering

Major Professor

David J. Keffer

Committee Members

Brian J. Edwards, Hank D. Cochran

Abstract

Kamat et al. has developed an analytical statistical mechanical theory that can be used to model pure component and binary liquid mixtures confined within crystalline nanoporous materials [1, 2]. The theory can be used to predict diffusivities, adsorption isotherms, and heats of adsorption as functions of temperature, pressure, and composition. The predictions obtained from this theory can then be used in macroscopic process level simulations to investigate the use of new adsorbents without conducting expensive experiments.

Kamat et al. has verified that the analytical adsorption theory can be used to model methane confined within zeolite Na-Y [3]. However, the diffusion theory failed to quantitatively model the self-diffusion coefficients for methane confined within Na-Y. Thus, an attempt has been made to improve the fit of the self-diffusion coefficients by incorporating the effects of percolation into the diffusion model. Incorporating the effects of percolation into the diffusion model did not improve the quantitative fit of the self-diffusion coefficients.

The analytical theory is generalizable and can be used for a variety of liquids confined within a variety of nanoporous materials. In this work, the theory is used to model pure component methane and pure component ethane confined within AlPO₄-5. The lattice parameters required for the theory are obtained by comparing the theoretical results to results obtained from molecular dynamics simulations. In this work, it has been proven that the theory is generalizable and can be used for different liquids confined within a nanoporous material.

The adsorption theory can also be used to model binary mixtures confined within nanoporous materials. The lattice parameters obtained from the pure component parameter optimizations are used to verify the analytical theory with binary mixtures. Results have been presented which indicate the binary theory does not accurately model a binary mixture confined within nanoporous materials. Problems arise both due to approximations within the theory as well as deviations of the real system from the lattice model.

Recommended Citation

Newman, Austin M., "Statistical Mechanical Models of Adsorption and Diffusion of Fluids in Crystalline Nanoporous Materials: Extensions to Percolation and Multicomponent Fluids. " Master's Thesis, University of Tennessee, 2004.
https://trace.tennessee.edu/utk_gradthes/2316