Second harmonic generation monitoring of nitric acid extraction by a monoamide at the water–dodecane interface

Abstract

The interface dynamic properties of a monoamide extractant with potential for application to the front end of the nuclear cycle and to waste treatment are examined by second harmonic generation. The results are compared with bulk nitric ion titration and surface pressure measurements. SH static studies show the extractant reaching the interface and accurately match the IFT measurements. The main feature of the SH dynamic studies is a chaotic fluctuation period, strongly related to intense extraction. Fluctuations are a signature of the interface behaviour during the extraction process. Vertical development of the interface, often called protrusion, remains the most probable origin of the measured fluctuation. Additionally, interfacial measurements show a non-monotonic lag time during extraction, probably related to cooperative effects not observed in the bulk at the working concentration. Such mutual behaviour could be a supplementary prerequisite for the ion transfer across this liquid-liquid interface.

Deciphering second harmonic generation signals

“…3,4 Therefore, SHG is widely employed to characterise equilibrium and dynamic physical-chemistry processes of all types of interfaces, including buried interfaces, as long as they are accessible by light, with a high sensitivity to layers of adsorbates or contaminants. [12][13][14] The interface-specificity of SHG was first attributed to the discontinuity of the electric field at the interface induced by the non-matching refractive indices, which results in the apparition of an interface quadrupole term in the induced polarisation a ICSM, Univ Montpellier, CEA, CNRS, ENSCM, Marcoule, France. E-mails: yann.foucaud@cea.fr; jean-francois.dufreche@icsm.fr b PASTEUR, Département de Chimie, Ecole normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.…”

Two-Step Adsorption of PtCl62– Complexes at a Charged Langmuir Monolayer: Role of Hydration and Ion Correlations

“…SX is also the main technique used in the refining and reprocessing of precious and rare earth metals , and nuclear waste . Although SX has been developed since the mid-20th century, very little is known about the molecular-scale interactions during the transfer of the ions through an aqueous/oil interface; these important interactions are expected to govern SX kinetics. − A detailed, molecular-level understanding of the interactions and structures that are present during metal–ion transfer is required to predict and develop SX and other solution processes to meet the high demands of modern technologies …”

Second-Harmonic Scattering Can Probe Hydration and Specific Ion Effects in Clay Particles

“…In the case B, the evolution shows a more fluctuating decrease and reached an equilibrium state of the same order of magnitude than in case A. These fluctuations 27 " c llap -driven exchange » is really preferred. These real time SHS data show that for the two different initial states studied here, the characteristic time of ion exchange is nearly the same.…”