On the Concentration Dependence of Second-Order Phenomenological Coefficients of Electrokinetic Phenomena

Abstract

An experimental investigation of electrokinetic phenomena is described which elucidates the influence of the composition of the liquid permeant on the secondorder phenomenological coefficients. In the whole range of variation of the composition of the ternary mixture acetone-water-2 propanol, the relationship between the hydrodynamic flux and the pressure drop was non-linear. The coefficient L ljL1 varied linearly with the composition and its value diminished as the mole fraction of 2-propanol increased. The square fluidity of the permeant varied also linearly with the composition. The ratio Lm/Φ 2 was independent of the composition, this proving that Φ 2 plays an important role in the explanation of the composition dependence of L 11JL . The phenomenological relationship between the streaming potential and the pressure drop was non-linear. The turbulence originated by the high values of applied pressure is probably the cause leading to the non-linear effect. The composition dependence of the coefficient L 2 n and L 212 was explained by means of Jha's equations.

Some Experimental Data Concerning the Effect of the Composition of Liquid Mixtures (Methanol-Ethanol) on the Electrophoretic Coefficient

“…Equation (17) gives much smaller values of the radius r than does (16). This fact seems to indicate that there exist two different mechanisms of transport through porous plug.…”

“…This last one is affected by the existence of the electrical double layer on capillary v/alls and its overlapping. This might explain that equation (17) yields smaller values than equation (16) one.…”

“…A linear dependence was also found for the coefficient L 12 , which represents the electroosmotic flow, against the composition of methanol-ethanol mixtures [1 5] . In some cases the dependence of the cross-phenomenological coefficients (first and second order) is explicable on the basis of changes in the characteristics of the permeant [3,16]. According to equation (6), a close correspondence between the variation of the values of 7 21 and the electrohydrodynamic properties of the permeant (ε τ !η) could be found.…”