A Thermodynamic Model on Liquid-Liquid Interfacial Adsorption

Area of Science:

• Physical Chemistry
• Thermodynamics
• Colloid and Surface Science

Background:

• Existing thermodynamic models struggle to predict interfacial behavior in complex multicomponent liquid systems.
• The surface aggregation adsorption (SAA) model successfully predicts surface tension and composition in homogeneous solutions.
• Understanding adsorption at liquid-liquid interfaces is crucial for various chemical processes.

Purpose of the Study:

• To develop a thermodynamic model, the interfacial aggregation adsorption (IAA) model, for predicting interfacial compositions in multicomponent two-phase systems.
• To establish a predictive framework for liquid-liquid interfacial adsorption based on existing SAA model parameters.
• To validate the IAA model using a representative ternary system.

Main Methods:

• Extension of the surface aggregation adsorption (SAA) model concepts to liquid-liquid interfaces.
• Development of the interfacial aggregation adsorption (IAA) model requiring only SAA parameters from binary solutions.
• Application and examination of the IAA model on a benzene-water-ethanol ternary system.

Main Results:

• The IAA model successfully predicts interfacial compositions in multicomponent two-phase systems.
• Ethanol was predicted to preferentially accumulate in the interfacial layer of the benzene-water-ethanol system.
• Interfacial ethanol content was shown to vary with bulk phase compositions.

Conclusions:

• The IAA model offers a novel predictive tool for adsorption phenomena at liquid-liquid interfaces.
• The model simplifies predictions by utilizing readily available SAA parameters from binary systems.
• This work enhances the understanding of molecular behavior and composition at interfaces in complex mixtures.