Further advancements in predicting adsorption equilibria using excess formalism: Calculation of adsorption excesses at the liquid/solid interface

Prediction of adsorption equilibria for ternary liquid mixtures on solid surfaces by means of adsorption data for the corresponding three binary liquid mixtures can be improved by combining the thermodynamic excess formalism with geometrical models. This new strategy for the prediction of excess adsorption isotherms is examined for four ternary adsorption systems ranging from ideal to highly non-ideal ternary mixtures. The predicted isotherms are discussed and compared with experimental ones as well as with those obtained for a model based on the absolute quantities. The results confirm: (i) superiority of predicting adsorption in terms of excess quantities, and (ii) utility of geometrical models for constructing ternary molar compositions on the basis of binary ones to predict equilibria not only for liquid mixtures alone but also for adsorption of liquid mixtures on solid surfaces.

The excess formalism for predicting adsorption from ternary liquid mixtures on solids on the basis of adsorption data for the corresponding binary liquid mixtures is combined for the first time with geometrical models. The superiority of models based on the excess quantities over those applying absolute quantities is confirmed and a bridge between adsorption and mixture thermodynamics built.Figure optionsDownload high-quality image (108 K)Download as PowerPoint slideResearch highlights
► The excess formalism for predicting adsorption from ternary liquid mixtures on solids on the basis of adsorption data for the corresponding binary liquid mixtures is combined for the first time with geometrical models.
► The prediction results of four ternary adsorption systems confirm: (i) superiority of models based on the excess quantities over those applying absolute quantities and (ii) utility of geometrical models to predict equilibria not only for liquid mixtures alone but also for adsorption of liquid mixtures on solid surfaces.
► A bridge between adsorption and mixture thermodynamics is built.