Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 370276
Title Electroosmotic flow phenomena in packed capillaries: From the interstitial velocities to intraparticle and boundary layer mass transfer
Author(s) Tallarek, U.; Rapp, E.; Seidel-Morgenstern, A.; As, H. van
Source The Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces & Biophysical 106 (2002)49. - ISSN 1520-6106 - p. 12709 - 12721.
Department(s) Biophysics
Publication type Refereed Article in a scientific journal
Publication year 2002
Keyword(s) size-exclusion chromatography - fibrous porous-media - pressure-driven flow - perfusion chromatography - magnetic-resonance - pore flow - electrokinetic remediation - hydrodynamic dispersion - forced-convection - fixed-beds
Abstract Pulsed field gradient nuclear magnetic resonance studies of electrokinetic flow through a 250 m i.d. cylindrical fused-silica capillary packed with spherical porous particles (dp = 41 m) have revealed the following phenomena and parameters: (i) An electrokinetic wall effect exists due to a mismatch of zeta-potentials associated with the capillary inner wall and the particles surface. It results in a transcolumn velocity profile which depends on the column-to-particle diameter ratio and causes additional longitudinal dispersion. (ii) Compared to the pressure-driven flow through the porous medium, the intraparticle mass transfer rate constant is significantly increased under the influence of a potential gradient. This increase also depends on the buffer concentration via electric double layer overlap. (iii) Fluid molecules in the porous particles remain diffusion-limited in the presence of a pressure gradient. By contrast, intraparticle Peclet numbers above unity have been measured for electroosmotic flow and were found to increase with the applied potential difference. (iv) Interparticle resistance to mass transfer appears to vanish on the pore scale when electric double layers are small compared to the relevant pore dimension
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