1. Selective ions are transferred from the aqueous phase into the organic phase thanks to complexing molecules present at the interface : extractants. Studied systems: -An organic phase : dodecane + monoamid: DEHiBA -An acid aqueous phase : nitrate ions Interfacial dynamic in liquid/liquid extraction processes probed by non linear optics P.M. Gassin (1), G. Martin-Gassin (1) (2),D. Meyer (1), J.F. Dufreche (1),O. Diat (1), E. Benichou (3), P. F. Brevet (3) (1) : Institut de Chimie Séparative de Marcoule (2) : CEA Marcoule/DRCP (3) : Laboratoire de Spectrométrie Ionique et Moléculaire, Université Lyon 1 - CNRS Organic Phase Aqueous Phase Complexed Ions Hydrated Ions Extractants Solvated Ions Liquid/liquid extraction processes are used in separation processes specially concerning nuclear fuel. What happened at the interface during extraction process ? What are characteristic times of extractants movements on the surface ? Liquid-Liquid extraction Non Linear Optics Interface structure Probing by polarization resolved SHG Probing interface structure by polarization resolved SHG -A /2 plate rotates the incident light polarization. -An analyzer selects the emergent light polarization Combined SHG and interfacial tension measurements Possible interpretation and outlook 'n_H+_22 Interface Dynamic SHG Fluctuation signature of acid extraction The dynamic of extraction can be view with 3 differents regimes: 1 : The SHG signal fall off because the DEHiBA adsorbes to the interface 2 : The SHG signal fluctuates. The maximum of the SHG standard deviation matches with the maximum flux across the interface 3 : Final Equilibrium state Real time SHG evolution after introduction of DEHiBA into organic phase at t=0s G. Martin-Gassin, PCCP submitted Interpretation of the fluctuation stage during the extraction : -It can be aggregate on the interface -It can be 3D developpement of the interface: protrusion - SHG dependence with [DEHiBA] similar to interfacial tension dependence. -No change in the polarisation signal with DEHiBA. - A possible interpretation is that DEHiBA perturbs and smoothes the sharp neat interface - Full surface coverage is reached at nearly 200 mM of DEHIBA ? ? ? Water dipole oriented on the liquid/liquid interface Water dipole perturbed by the DEHiBA Interpretation: Next step : 1) Working with a new molecule, both chromophore and extractant to enhanced SHG signal. 2) To quantify the fluctuations by analysis SHG fluctuations with autocorrelation function 3) To develop a new setup in order to mesure simultaneously SHG signal and Interfacial tension. CH 3 (CH 2 ) 17 Luciferine Complexation site Protrusions G.Wipff, JPC C, 2009 Protrusion, ondulations, Léontidis, JPC B, 2009 Roughness Benjamin, CPL, 2009 Laser Chopper Sample in petri dish Photon counting device half wave plate Analyzer aliphatic Chains Complexation site Second Harmonic Generation (SHG) is a nonlinear optical phenomenon involving the conversion of two photons at the fundamental frequency into one photon at the harmonic frequency. In centrosymmetric bulk materials, SHG is forbidden in the electric dipole approximation. SHG is therefor surface specific at the nanometer scale. Zoom x10 6 ~ 1 nm P-output SSHG intensity as a function of the input polarization angle. Lines are the fitted curve.