Equivalence between Nernst-Planck and ''corrected'' Fick's law in modeling fixed-bed ion exchange processes

• Type: Article in International Scientific Journal
• Date: 1996

Authors

delaVega, MR (Author) Other; José Miguel Loureiro (Author) FEUP; Alírio Rodrigues (Author) FEUP

Journal

Title: Chemical Engineering Journal and the Biochemical Engineering Journal

Vol. 61 No. 2

Pages: 123-132

ISSN: 0923-0467

Publisher: Elsevier B.V.

Indexing

ISI Web of Knowledge - 7 Citations

ISI Web of Science

Scopus - 8 Citations

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Other information

Authenticus ID: P-001-ET6

Abstract (EN): An equivalence between the Nernst-Planck approach, which takes into account the diffusive and electrical contributions for intraparticle mass transfer, and Fick's law, which considers only the diffusive contribution, is developed in this paper. This equivalence leads to the determination of a ''corrected'' diffusivity that enables the simulation of ion-exchange processes with the Fick approach. The development is based on the comparison of the behavior of the processes in an infinite bath, measured by the filling times for the particles; the ''corrected'' Fick diffusivity obtained is tested against the solution with the Nernst-Planck model for column ion-exchange processes. It is able to simulate the processes in all but the cases when favorable equilibrium and kinetics coexist. To cope with this situation, another equivalence is developed based on the variance of the derivative of the breakthrough curves. The same test shows that this last approach is able to simulate all the situations.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10