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A comparative study on the free volume theories for diffusivity through polymeric membrane in pervaporation process
Author(s) -
Mafi Amirhossein,
Raisi Ahmadreza,
Hatam Mohsen,
Aroujalian Abdolreza
Publication year - 2014
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.40581
Subject(s) - pervaporation , membrane , permeation , polydimethylsiloxane , thermodynamics , thermal diffusivity , sorption , chemistry , diffusion , aqueous solution , volume (thermodynamics) , mass transfer , chemical engineering , polymer chemistry , chromatography , organic chemistry , adsorption , physics , biochemistry , engineering
In this work, free volume theories are coupled with a thermodynamic model and generalized Fick's law to develop a mass transfer model based on solution‐diffusion mechanism for pervaporation process with a hydrophobic polymeric membrane. The Wesselingh, Fujita and Vrentas‐Duda's theories are used to calculate concentration‐dependent diffusion coefficient of permeants inside polydimethylsiloxane membrane. The sorption and pervaporation experiments on aqueous ethanol solutions are performed to validate the sorption and pervaporation models. The results reveal that the proposed models are able to predict influences of feed concentration and temperature as well as permeate‐side pressure on partial fluxes through the membrane. The comparative investigation indicated that Wesselingh's free volume theory underestimated the diffusion coefficients inside the membrane and the accuracy of the model used this theory is very low for prediction of the permeation flux. Generally, Fujita and Vrentas‐Duda's theories are found to be much more accurate especially for dilute aqueous feed solutions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40581.