par Pétré, Georges ;Schayer-Polischuk, Marie-Louise
Référence Electrochimica acta, 15, 6, page (909-921)
Publication Publié, 1970
Article révisé par les pairs
Résumé : The Gibbs adsorption equation is written for aqueous solutions containing a partially dissociated fatty acid, KOH and KCl. Experimentally obtainable quantities are chosen as independent variables: concentration of the fatty acid, pH and concentration of the K+ ions. Assumptions and approximations are: 1. the solution is dilute and ideal; 2. the liquid surface is neutral electrically; 3. the adsorption of fully dissociated species (except for KA) and the adsorption of negative ions other than A- are negligible. The knowledge of the surface tension as a function of the given independent variables allows us to compute the number of adsorbed hydrocarbon chains A adsorbed per cm2, the number of H atoms adsorbed (AH and H+, the number of K+ atoms adsorbed (KA and K+) and also the dissociation constant of the fatty acid in the bulk. The equation is applied to heptanoic acid solutions. © 1970.