The Kelvin Capillary Phenomena in Chromatography and its Influence upon the Determination of Adsorption Coefficients

Equations have been developed that show that the chromatographic retention volume is affected by capillary phenomena that occur in the pores of the support and which are related to the Kelvin effect. This “Kelvin retention” can be determined and turns out to be an important part of the overall surface retention, unless the solute under study is not soluble in the stationary phase. A correction should thus be applied to the chromatographic measurements of gas-liquid adsorption coefficients. The correction to the partition coefficient can be made negligible

Structure et inversion de phase des microemulsions en correlation avec l'obtention de basses tensions interfaciales (Rôle de l'alcool — rôle de la salinité)

L'analyse des diagrammes des phases pseudo-ternaires et des mesures de tensions interfaciales permet aux auteurs de discuter du rôle parallèle de la concentration du sel et de la concentration de l'alcool sur l'obtention de systèmes triphasiques du type Winsor III et sur l’obtention de basses tensions interfaciales. Quoique similaire, l'influence du sel et de l'alcool ne semble pas pouvoir être interprétée de la même façon. L'analyse détaillée des forces d'interactions dans les microémulsions n’en est encore qu'à un stade très peu avancé et seules des hypothèses peuvent être émises pour expliquer le rôle respectif de ces deux constituants. En raison des faibles distances interparticulaires observées dans ces systèmes, l'analyse de leur stabilité pourrait ne plus relever seulement de la simple théorie de D.L.V.O. D'autres forces à plus courte portée, ainsi que des tensions d'arête pourraient jouer un rôle déterminant

True Temperature Coefficients of the Electric Tension of Individual Electrodes II. [Fe(CN)6]4− -[Fe(CN)6]3− Electrode

The [formula omitted] electrode was thoroughly investigated to ascertain whether, in addition to the influence of the activity coefficients, association phenomena should also be considered in studying the true temperature coefficients of the electric tension of individual electrodes. The influence of the associations (first step): [formula omitted] and the corresponding ones with Na+ ions on the true temperature coefficient of this electrode is shown. © 1967, Walter de Gruyter. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

A Local Thermodynamical Approach of Spherical and Plane Electrochemical Diffuse Layer

A local thermodynamic method was employed to calculate the potential, the field, and the surface charge in the diffuse layer around a colloidal particle. It was found that the effect of the molar volume of the counterions and the effect of the polarization were to lower the local concentration of the counterions and thus to reduce the surface charge for a given surface potential. The ratio of the surface charge calculated by this theory to that calculated by the Gouy-Chapman theory does not change significantly with the curvature of the colloidal particle. A limitation in the application of this theory is due to the lack of knowledge of the activity coefficients at zero field in the diffuse layer. Two nomograms (graphs) of the potential versus charge relation are presented. © 1968.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Interaction de sphères colloïdales et coefficient du viriel

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True Temperature Coefficients of the Electric Tension of Individual Electrodes III. Ag\AgCl\ Cl− Electrode

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Influence of Tetraisoamylammonium Picrate on the Repulsive Energy Between Colloidal Particles in Benzene

A study was made on the influence of molar volumes and of polarization of tetraisoamylammonium picrate in benzene on the repulsive energy between spherical colloidal particles. The spherical colloidal particles (radius 1 μ) are taken to be at a negative constant surface potential. In comparison with the classical Derjaguin-Landau and Verwey-Overbeek theories, we observe a large increase of the repulsive energy due to the strong polarizability of the tetraisoamylammonium cation, whereas the finite molar volume of this cation weakly decreases the repulsion. All the effects (polarizability, molar volume) increase with the surface potential and the concentration of the solute. © 1971.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

A local thermodynamical approach of the repulsive energy between colloidal particles

The influence of molar volumes and of polarization of the electrolyte on the repulsion energy and on the second virial coefficient was studied. With the same superficial charge, the values of the second virial coefficients calculated for different electrolytes are slightly higher (a few per cent) than those calculated with Vrij's classical theory, and the observed sequence is: HCl > LiCl > NaCl > Verwey-Overbeek With the same surface potential, we observe larger differences and an inversion of the sequence observed before. The differences are larger when (1) the dimensions of the colloid are small, (2) the concentration of the electrolyte is large, and (3) the surface potential is high. Finally, the influence of the nonideality of the solution gives larger differences. © 1970.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Influence of Molar Volumes, Polarization and Activity Coefficients on the Repulsion Between Two Plane Layers

Using the local thermodynamics of continuous media,the distribution of the potential in a system consisting of two plane layers between conducting plates, for a set of electrolytes, is derived. The difference between the electrical potential of the median plane and that of the plates is greater (in absolute value) than the difference predicted by the Gouy-Chapman distribution. The data permit the evaluation of the electrostatic repulsion between the two layers, with a formula obtained previously. The calculations stress the influence of the ion molar volume and also of the polarization. For a given surface potential and interplate distance, the effects lead to a repulsion force weaker than that obtained by the classical Derjaguin-Verwey-Overbeek expression. On the other hand the discrepancies due to activity coefficients lead to a repulsion that can be weaker or stronger than that obtained from the Derjaguin-Verwey-Overbeek expression. © 1968.En étudiant la thermodynamique locale des milieux continus sur une série d'électrolytes, on déduit la distribution du potentiel dans un système formé de deux couches planes entre des lames conductrices. La différence entre le potential électrique du plan médian et celui des lames, est plus grande (en valeur absolue) que celle prédité par la distribution de Gouy—Chapman. Les données permettent l'évaluation de la répulsion électrostatique entre les deux couches, au moyen d'une formule obtenue antérieurement. Les calculs font ressortir l'influence du volume molaire ionique et aussi de la polarisation. Pour un potential de surface et une distance des lames données, les effets conduisent à une force de répulsion plus faible que celle déduité de l'expression classique de Derjaguin—Verwey—Overbeek. D'autre part, la différencé due aux coefficients d'activité conduit à une répulsion qui peut être soit plus faible, soit plus forte que celle obtenue à partir de l'expression de Derjaguin—Verwey—Overbeek.SCOPUS: ar.jinfo:eu-repo/semantics/publishe