Ions at interfaces: accessing the first nanometers using X-ray standing waves - CEA - Commissariat à l’énergie atomique et aux énergies alternatives Access content directly
Conference Poster Year : 2017

Ions at interfaces: accessing the first nanometers using X-ray standing waves

Abstract

Ion-surface interactions are of high practical importance in a wide range of technological, environmental and biological problems. In particular, they ultimately control the electric double layer structure, hence the interaction between particles in aqueous solutions. Despite numerous achievements, progress in their understanding is still limited by the lack of experimental determination of the surface composition with appropriate resolution. In the present work, we have developed a method based on X-ray standing waves coupled to nano-confinment which allows the determination of ion concentrations at a solid-solution interface with a sub-nm resolution. We have investigated mixtures of KCl/CsCl and KCl/KI in 0.1mM to 10mM concentrations on silica surfaces and obtained quantitative information on the partition of ions between bulk and Stern layer as well as their distribution in the Stern layer. Regarding partition of potassium ions, our results are in agreement with a recent AFM study. We show that in a mixture of KCl and KI, chloride ions exhibit a higher surface propensity than iodide ions, having a higher concentration within the Stern layer and being on average closer to the surface by $\sim$ 1-2 $\mathring{A}$, in contrast to the solution water interface. Confronting such data with molecular simulations will lead to a precise understanding of ionic distributions at aqueous interfaces.
Fichier principal
Vignette du fichier
Malloggi_Flow17_2017b.pdf (273.36 Ko) Télécharger le fichier
Origin : Files produced by the author(s)
Loading...

Dates and versions

cea-02341903 , version 1 (31-10-2019)

Identifiers

  • HAL Id : cea-02341903 , version 1

Cite

Soumaya Ben-Jabrallah, Florent Malloggi, Luc Belloni, Luc Girard, Dmitri Novikov, et al.. Ions at interfaces: accessing the first nanometers using X-ray standing waves. Flow17, Jul 2017, Paris, France. ⟨cea-02341903⟩
37 View
34 Download

Share

Gmail Facebook X LinkedIn More