Liquid-liquid extraction processes are widely used in the industrial fields of selective separation. Despites its numerous applications, the microscopic mechanisms which occur during a liquid-liquid extraction processes are really unknown specially at the liquid liquid interface. Thus, this work deals on the understanding of the phenomena which drive the mass transfer across a liquid liquid interface. Two experimental techniques were used in this work: dynamic interfacial tension measurement and non-linear optical experiments. Along with the use of this experimental approach, a numerical model describing the mass transfer dynamic has been developed. This model works under the assumption that both diffusion and a chemical step describing adsorption and desorption processes contribute to the global transfer kinetics. Model systems of surfactant molecules, chromophore molecules and complexing molecule were investigated at liquid/liquid and air/liquid interface. Interfacial phenomena like adsorption, surface aggregation and ion complexing were studied. Finally, the methodology developed in this work was applied to study an extractant molecule with potential industrial application.
