Preferential Adsorption in Mixed Electrolytes Confined by Charged Amorphous Silica - CEA - Commissariat à l’énergie atomique et aux énergies alternatives Accéder directement au contenu
Article Dans Une Revue Journal of Physical Chemistry C Année : 2019

Preferential Adsorption in Mixed Electrolytes Confined by Charged Amorphous Silica

Résumé

Preferential ion adsorption in mixed electrolytes plays a crucial role in many prac- tical applications, such as ion sensing and separation and in colloid science. Using all-atom Molecular Dynamics simulations of aqueous NaCl, CaCl2 and NaCl CaCl2 solutions confined by charged amorphous silica, we show that Na+ ions can adsorb preferentially over Ca2+ ions, depending on the surface structure. We propose that this occurs when the local surface structure sterically hinders the first hydration shell of the Ca2+ ion. Introducing a protrusion metric as a function of protrusion and ori- entation of deprotonated silanols, ion-specificity is successfully predicted on isolated, vicinal and geminal silanols alike, provided that no other deprotonated silanols are found nearby. Furthermore, we introduce a new strategy to analyze the results as a function of distance to the surface. This approach effectively removes surface roughness effects allowing for direct comparison with classical Electric Double Layer theory and distinction of specifically adsorbed ions and electrostatically adsorbed ions.
Fichier non déposé

Dates et versions

cea-04117823 , version 1 (05-06-2023)

Identifiants

  • HAL Id : cea-04117823 , version 1

Citer

Max F. Döpke, Johannes Lützenkirchen, Othonas A. Moultos, Bertrand Siboulet, Jean-François Dufreche, et al.. Preferential Adsorption in Mixed Electrolytes Confined by Charged Amorphous Silica. Journal of Physical Chemistry C, 2019, 123, pp.16711-16720. ⟨cea-04117823⟩
13 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More