RES³T - Rossendorf Expert System for Surface and Sorption Thermodynamics

The expressions developed recently by us to describe the temperature dependence of the titration curves are used to describe the calorimetric effects accompanying ion adsorption at the oxide/electrolyte interface. For the purpose of illustration the data obtained by “calorimetric titration” of TiO₂ suspension in NaCl were subjected to a quantitative analysis, based on the developed equations. A proper choice of adsorption parameters leads to a quantitative agreement between both the experimental and theoretical titration curves, and between the experimental and theoretical heats of proton adsorption at different pH values. This quantitative analysis shows the risk of a simple interpretation on a qualitative level of the enthalpic effects accompanying ion adsorption. This is because the recorded enthalpic effects carry complicated information about the enthalpic effects of various surface (complexation) reactions occurring simultaneously.