CONVECTIVE DIFFUSION IN POROUS MEMBRANES WITH ADSORBED CHARGES

Citation
Ak. Kontturi et al., CONVECTIVE DIFFUSION IN POROUS MEMBRANES WITH ADSORBED CHARGES, Langmuir, 10(3), 1994, pp. 949-954
Citations number
25
Categorie Soggetti
Chemistry Physical
Journal title
ISSN journal
07437463
Volume
10
Issue
3
Year of publication
1994
Pages
949 - 954
Database
ISI
SICI code
0743-7463(1994)10:3<949:CDIPMW>2.0.ZU;2-8
Abstract
We have studied experimentally the effects that the charge adsorbed on the membrane pore walls exerts on the convective diffusion through a porous membrane. The plot of the logarithm of the bulk concentration r atio vs convective flow through the membrane is usually employed to de termine the membrane parameter A/L (effective membrane area/membrane t hickness). It is shown that the deviations from the linear behavior of this plot give us information on the adsorbed charge concentration. A simple model based on the Nernst-Planck equation for the ion fluxes a nd the Navier-Stokes equation for the pore fluid velocity has proved t o be useful for the understanding of the experimental trends observed over a range of membrane pore radius and electrolyte concentration. Ou r study can be seen as an independent confirmation of a rather general result: ion adsorption to the pore walls of inert, porous membranes c an significantly affect the transport phenomena, especially in the lim it of low electrolyte concentration.