Résumé
Ion separation by liquid-liquid extraction (LLE) is a process based on the difference inaffinity of a solute between two phases that are not miscible with each other. In orderto increase the affinity of the solute to be extracted, a transfer agent called extractantmolecule is usually added. As LLE is the key to various industrial hydrometallurgicalprocesses, a detailed knowledge of the supramolecular structuring of these interfacescontaining amphiphilic-extracting molecules is essential for understanding this iontransfer phenomena. Unfortunately, experimental data allowing accessing to structuralinformation from these interfaces are almost inexistent. For the first time thecombination of x-ray and neutron reflectivity experiments made possible the access ofthese information.[1,2] The analysis of these measurements shows that trivalent cationscan be repelled or attracted by an interface enriched with extractant depending on thenature of the molecule. The experimental structure observed being the result of thecomplex processing of many reflectivity data; it was interesting to see if molecularmodelling (MD) could give comparable results without preliminary hypothesis on thesurfactant. MD simulations of real solutions have been performed taking into accountexplicitly the polarization effects of all the atoms using the AMBER software.[3] The comparison of measurement and MD results supports not only the measurement andanalysis of large instrument fates but also the parameters applied in MD simulations.