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Title: Flux Equations for Osmotically Moderated Sorption–Diffusion Transport in Rigid Microporous Membranes

Abstract

The development of non-aqueous reverse osmosis separations via the use of rigid microporous membrane materials suggests that flux equations originally developed for swellable polymeric membranes should be revisited. This paper demonstrates that the gradient of fractional occupancy of penetrant molecules within the micropores of the membrane is the driving force for permeation without requiring assumptions about pressure within the membrane. Flux equations are derived using both Fickian and Maxwell-Stefan approaches, and different behavior in the permeate flux versus upstream hydraulic pressure relationship is shown to arise as a result of differences in the loading dependence of the single component Maxwell-Stefan diffusivity. Molecular modeling results available in the literature and experimental data obtained from carbon molecular sieve (CMS) membranes showcase that these loading-dependent changes in the Maxwell-Stefan diffusivity are possible. This loading dependence is separated into three regimes: so-called “weak confinement” diffusion and “strong confinement” diffusion, both of which have been discussed at length in the literature, and a new “hybrid confinement” diffusion, which is introduced here. Furthermore, the separation mechanism of solvent molecules through a rigid bimodally microporous membrane is studied using xylene molecules passing through CMS membranes fabricated under different conditions as examples. Altogether, this study provides fundamental insightmore » and guidance into osmotically-moderated sorption-diffusion transport of solvent molecules through rigid microporous membranes.« less

Authors:
ORCiD logo [1]; ORCiD logo [1];  [2]; ORCiD logo [1]; ORCiD logo [1]
  1. Georgia Inst. of Technology, Atlanta, GA (United States)
  2. ExxonMobil Research and Engineering, Annandale, NJ (United States)
Publication Date:
Research Org.:
Georgia Tech Research Corp., Atlanta, GA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1593887
Grant/Contract Number:  
SC0019182
Resource Type:
Accepted Manuscript
Journal Name:
Industrial and Engineering Chemistry Research
Additional Journal Information:
Journal Name: Industrial and Engineering Chemistry Research; Journal ID: ISSN 0888-5885
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Separations; Carbon; Transport properties; Fluxes; Diffusion; Molecules; Membranes

Citation Formats

Ma, Yao, Zhang, Fengyi, Deckman, Harry W., Koros, William J., and Lively, Ryan P. Flux Equations for Osmotically Moderated Sorption–Diffusion Transport in Rigid Microporous Membranes. United States: N. p., 2019. Web. doi:10.1021/acs.iecr.9b05199.
Ma, Yao, Zhang, Fengyi, Deckman, Harry W., Koros, William J., & Lively, Ryan P. Flux Equations for Osmotically Moderated Sorption–Diffusion Transport in Rigid Microporous Membranes. United States. doi:10.1021/acs.iecr.9b05199.
Ma, Yao, Zhang, Fengyi, Deckman, Harry W., Koros, William J., and Lively, Ryan P. Wed . "Flux Equations for Osmotically Moderated Sorption–Diffusion Transport in Rigid Microporous Membranes". United States. doi:10.1021/acs.iecr.9b05199.
@article{osti_1593887,
title = {Flux Equations for Osmotically Moderated Sorption–Diffusion Transport in Rigid Microporous Membranes},
author = {Ma, Yao and Zhang, Fengyi and Deckman, Harry W. and Koros, William J. and Lively, Ryan P.},
abstractNote = {The development of non-aqueous reverse osmosis separations via the use of rigid microporous membrane materials suggests that flux equations originally developed for swellable polymeric membranes should be revisited. This paper demonstrates that the gradient of fractional occupancy of penetrant molecules within the micropores of the membrane is the driving force for permeation without requiring assumptions about pressure within the membrane. Flux equations are derived using both Fickian and Maxwell-Stefan approaches, and different behavior in the permeate flux versus upstream hydraulic pressure relationship is shown to arise as a result of differences in the loading dependence of the single component Maxwell-Stefan diffusivity. Molecular modeling results available in the literature and experimental data obtained from carbon molecular sieve (CMS) membranes showcase that these loading-dependent changes in the Maxwell-Stefan diffusivity are possible. This loading dependence is separated into three regimes: so-called “weak confinement” diffusion and “strong confinement” diffusion, both of which have been discussed at length in the literature, and a new “hybrid confinement” diffusion, which is introduced here. Furthermore, the separation mechanism of solvent molecules through a rigid bimodally microporous membrane is studied using xylene molecules passing through CMS membranes fabricated under different conditions as examples. Altogether, this study provides fundamental insight and guidance into osmotically-moderated sorption-diffusion transport of solvent molecules through rigid microporous membranes.},
doi = {10.1021/acs.iecr.9b05199},
journal = {Industrial and Engineering Chemistry Research},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {11}
}

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This content will become publicly available on November 27, 2020
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