The adsorption of potassium biphthalate at the AgI/Electrolyte solution interface from solutions of constant ionic strength

Abstract

Based on the Gibbs adsorption isotherm, an equation is derived for the determination of the adsorbed amount of biphthalate from double layer capacitance measurements. In this derivation allowance is made for the dissociation and association of the biphthalate ion. The final adsorption equation is applied to the twice integrated curves of the double layer capacitance as a function of the potential at the interface between AgI and KNO 3 + K-biphthalate solutions of constant ionic strength. The best fit of the experimental results was obtained with a virial isotherm.