Is a universal model to describe liquid-liquid extraction of cations by use of ionic liquids in reach?

A general chemical model describing the extraction mechanism of cations from an acidified aqueous phase toward an ionic liquid phase in which an extracting agent is dissolved is proposed. On this basis, fits are made which recover very satisfactorily the variation of the distribution ratio as a function of [HNO3] for several experimental data sets from the literature. This chemical model is discussed and compared to another model.