Irreversible thermodynamics of transport processes through porous media composed of particles of different size

An experimental investigation on the electrokinetic transport of ternary and binary mixtures through inactive membranes is described. Pyrex glass and quartz were used to perform the porous membranes. The phenomenological equations between the thermodynamic fluxes and forces were always found to be linear. The geometric parameters of the porous membranes were found to be independent on the composition of the mixture. The concentration dependence of the coefficients L 21 and L 22 in the Pyrex-binary mixture systems was non-linear. A similar dependence was found for D/T? (D, dielectric constant; τ?, absolute viscosity) with the composition of the binary mixture. The concentration dependence of the L n and L 22 coefficients was linear for the quartz-ternary mixture systems. Similar trends were found for the reciprocal of the absolute viscosity (η"" 1 ) and the specific electrical conductivity (λ) of the ternary mixtures. Onsager's reciprocity relation was experimentally verified and found to be obeyed within the experimental error. The variations of the coefficients L 12 and L 21 with the composition of the ternary mixtures was non-linear, although less pronounced than that obtained for the binary mixtures. The results confirm the decisive influence of the physical properties of the liquid mixture on the actual values of the electrokinetic transport coefficients.

Section: Methodsmentioning

confidence: 99%

Concentration Dependence of Transport Coefficients of Binary and Ternary Mixtures Through Inactive Membranes

Hidalgo‐Álvarez¹,

González‐Caballero²,

Nieves³

1982

“…The experimental devices and procedures for hydrodynamic permeability, streaming potential and electroosmosis measurements were the same as those described earlier [12][13]. The interruption technique described by Lakshminarayanaiah [1], was followed in the determination of electroosmotic flux.…”

Section: Methodsmentioning

confidence: 99%

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

Hidalgo‐Álvarez¹,

Nieves²,

Pardo³

1984

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.

“…j = L ij + ^kL iJk X k + ... 9 (12) which provides the explicit relationship between the coefficients.…”

Section: Theorymentioning

confidence: 99%

“…The experimental setup and procedure followed for hydrodynamic permeability and electroosmotic permeability measurements were the same as described earlier [6,12]. For the determination of the electroosmotic flux, the desired potential difference was applied across the plug with an electrically operated power suply, Kepco OPS 1000.…”

Section: Materials and Proceduresmentioning

confidence: 99%

On the Use of Generalized Onsager Coefficients in Nonlinear Electroosmotic Phenomena

González-Fernández¹,

Bruque²,

González‐Caballero³

et al. 1984

An investigation on non-linear electroosmotic phenomena of porous plugs of cellulose is described. The variation of the electrokinetic coefficients as a function of fibre concentration in the porous pad has been studied, using dimethyl-ketone as a permeant. Second-order coefficients have been interpreted in terms of modifications of generalized coefficients, produced by the changes of thermodynamic forces.