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Coupled diffusion of water and ethanol in a polyimide membrane
Author(s) -
Ni Xiuyuan,
Sun Xiaohui,
Ceng Dong,
Hua Fengjun
Publication year - 2001
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.10843
Subject(s) - thermodynamics , permeation , diffusion , fick's laws of diffusion , solubility , materials science , membrane , work (physics) , mass transfer , coupling (piping) , ethanol , sorption , flux (metallurgy) , pervaporation , chemistry , organic chemistry , adsorption , physics , composite material , biochemistry , metallurgy
In this work, the sorplion and steady state permeation of water‐ethanol mixture in an aromatic polyimidc membrane was investigated with the objective of revealing the coupling cherts of water and ethanol in their course of diffusion. The solubility of the watcr‐ethanol mixture in the membrane was determined by means of swelling‐distillation techniques. The sorption behavior was interpreted in terms of the thermodynamic equilibrium equations. The Maxwell‐Stefan mass transfer model was employed as a framework for modeling diffusion. Model equations derived therefrom enable us to cplculate coupled fluxes of water and ethanol from the experimental data. The coupling effects in the diffusion of water and ethanol were revealed by comparing the calculated coupled flux with non‐coupling flux, which was calculated by integration of the Fickian first law using independent diffusion coefficients. Furthermore, the implication of the sole adjustable parameter included in the derived model equations was discussed.