Anomalous Electroosmotic Flow Through a Heteroporous Ion-Exchange Membrane. A Test Based Upon the Reciprocity Relations

Abstract

An experimental investigation about anomalous electroosmotic transport through an ion-exchange membrane is described. The thermodynamic consistency of the electroosmosis data has been analyzed by means of reciprocity relations. The dependence of the W-coefficients (elecroosmotic and streaming potential) on the external electrolyte concentration has been studied by the classical theory of electrokinetic phenomena. Our results seem to confirm that the most favourable conditions in which an anomalous electroosmotic flow appears are heteroporous membranes with a high water content, a very low current density and very dilute solutions.

Electrokinetic Energy Conversion in Heterogeneous Ion-Exchange Plugs

“…The characteristics of the ionic plugs and their porosities are given in Table 1. The hydrodynamic, electric and electrokinetic properties of these plugs have been reported in previous papers [7][8][9][10][11][12][13]; where the experimental devices and procedures for streaming potential, electrical conductance and electroosmotic and hydrodynamic permeabilities measurements have also been described.…”

“…The three plugs were prepared with 50% Teflon and resin particles in Na 4 " form with different degrees of D. V.B. The other characteristics of the plugs can be seen in [8,9].…”

“…In order to estimate η τηΛΧ for each plug and solution, we determined beforehand the phenomenological coefficients Z/ ll5 L 2 2> ^21 an d ^12 [8][9][10]. In previous papers [8,9] we have shown Onsager's reciprocity is fulfilled and thus, e is equal to s and the values of *7 max can be calculated using equations (3) and (4).…”

“…In previous papers [8,9] we have shown Onsager's reciprocity is fulfilled and thus, e is equal to s and the values of *7 max can be calculated using equations (3) and (4). The results for i7 max are shown in Figures 4, 5 and 6 for each plug and different electrolyte concentration.…”