The impact of the competitive adsorption of ions at surface sites on surface free energies and surface forces
Parsons, DF;SALIS, ANDREA
2015-01-01
Abstract
The relationship between surface charge and surface potential at the solid-liquid interface is often determined by a charge regulation process, the chemisorption of a potential determining ion such as H+. A subtle ion-specific effect can be observed when other ions compete with the primary potential determining ion to bind to a surface site. Site competition may involve alternative ions competing for a first binding site, e.g., metals ions competing with H+ to bind to a negatively charged oxide or carboxyl site. Second-binding sites with site competition may also be found, including amphoteric OH2 + sites, or anion binding to amine groups. In this work, a general theoretical model is developed to describe the competitive adsorption of ions at surface sites. Applied to the calculation of forces, the theory predicts a 20% increase in repulsion between titania surfaces in 1 mM NaCl, and a 25% reduction in repulsion between silica surfaces in 0.1M NaCl compared to calculations neglecting ion site competitionFile | Dimensione | Formato | |
---|---|---|---|
2015 1.4916519.pdf accesso aperto
Descrizione: Articolo principale
Tipologia: versione editoriale
Dimensione 876.18 kB
Formato Adobe PDF
|
876.18 kB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.