How Phase Modifiers Disrupt Third-phase Formation in Solvent Extraction Solutions

The structure of complex organic solutions based on N,N,N’,N’-tetraoctyldiglycolamide (TODGA) used in actinide separation processes were characterized after water and neodymium extraction. phases using FTIR spectroscopy, ESI-MS spectrometry, Small Wide Angle X-ray Scattering (SWAXS) molecular dynamic simulations. role the “phase modifier” like 1-octanol (used innovative SANEX process) or “co-extractant” DMDOHEMA (used, for example, EURO-GANEX added to phase avoid third-phase formation was investigated at supramolecular scales. Without metallic cations 0.2 mol/L TODGA solution n-heptane, molecules are organized monomers small aggregates containing mainly two three molecules. After Nd(NO3)3 extraction, complexes formed which each cation is surrounded average by 2 4 TODGA, 3 nitrate ions 1 Polymetallic species (aggregates) may also be formed. Adding 5%Vol 0.5 n-heptane leads mixed octanol These both interact directly with extracted phase, modifying species, improving their solubility this phase. At least one molecule remains first coordination sphere cases preserves its significant complexation/selectivity cations. But it clear that have a speciation phase: replaces Nd, acting as co-surfactant; drives organization partially replace Nd.