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Full Paper
Influence of the Non-Perfect Step Input Concentration at the Feed Side of the Membrane Surface on the Diffusion Coefficient Evaluation
Article first published online: 18 APR 2006
DOI: 10.1002/mats.200500073
Copyright © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Additional Information
How to Cite
Cermakova, J., Fialova, K., Petrychkovych, R., Kudrna, V. and Uchytil, P. (2006), Influence of the Non-Perfect Step Input Concentration at the Feed Side of the Membrane Surface on the Diffusion Coefficient Evaluation. Macromol. Theory Simul., 15: 246–251. doi: 10.1002/mats.200500073
Publication History
- Issue published online: 18 APR 2006
- Article first published online: 18 APR 2006
- Manuscript Accepted: 5 JAN 2006
- Manuscript Revised: 4 JAN 2006
- Manuscript Received: 12 OCT 2005
- Abstract
- Article
- References
- Cited By
Keywords:
- diffusion;
- dispersions;
- gas permeation;
- modeling;
- time-dependent input concentration
Abstract
Summary: Vapor diffusion coefficients in polymeric membranes were evaluated from dynamic permeation experiments. A membrane separated the diffusion cell into two parts – upstream and downstream. At the start of the experiment the concentration change in the upstream part (feed side) was made by substituting the input stream of pure nitrogen by the stream of permeant vapors. The solution of the Fick's second law with the step input concentration function is used for the evaluation of diffusion coefficients. The realization of the step input function can be difficult and its imperfection can negatively influence the evaluation process. This contribution deals with the description of the experimentally obtained input function and the study of its influence on evaluated values of diffusion coefficients. The mathematical model, which includes the non-perfect step input concentration function and the transport through a polymer was developed. The results of this study enable the estimation of diffusion coefficient evaluation errors as dependence on the experimental arrangements and on the membrane transport properties.