(95f) Mesoscale Modeling of Liquid-Liquid Solvent Extraction from Soft Matter Approach

Solvent extraction plays a very important role in the field of nuclear industry to reprocess the nuclear fuel. The separation technique is the basic principle behind liquid-liquid solvent extraction procedure where an aqueous electrolyte solution comes in contact with an ampiphilic extractant in the organic phase to be selectively extracted from the aqueous phase. All these chemical species are in equilibrium with each other during extraction procedure. From the previous studies, it has been found that such type of solvent extraction process involves the formation of inverse micelle of certain aggregation number of N free extractant monomers. The extraction properties is found to be influenced by the formation of the reverse micelle in the organic phase. The packing parameter of micelle plays a very significant role during the transfer of solute from the aqueous phase to the organic phase affecting the curvature of the micelle. From the study of Leodidis and Hatton, it is known that the free energy of transfer varies within the curvature of the interfacial film monotonically. The extractant film is characterized by its spontaneous packing parameter (of the order of 4) and its intrinsic rigidity of the order of 6.25 kJ mol^-1 (2.5 k_BT). This multiscale study combining supramolecular chemistry and mesoscale modelling approach allows for reducing largely the number of parallel apparent equilibria currently used for dimensioning extraction devices. Prediction power versus variations of water activity and temperature are in reasonable agreement with observations made in typical pilot cascades.