The effect of the discrete nature of ions on the excess adsorption of Na⁺ and Cl^- at the silica-aqueous interface

Abstract:

Wet pastes of silica, prepared by centrifugation of dispersions (with a salt concentration of 100 mM NaCl) that subsequently were decanted the supernatant, were analysed using X-ray photoelectron spectroscopy. The uptake of Na and Cl ions by the wet pastes were quantified and compared with pbkp_redictions based on the Gouy-Chapman (GC) concept, the triple layer model (TLM), and a modified TLM, which takes into account the discrete ion effect. The most striking feature of the results is that the Cl uptake increases by a factor of ∼2 with increasing surface counter charge, which has been explained on the basis of the discrete nature of ions. © 2005 Elsevier B.V. All rights reserved.

Año de publicación:

2005

Keywords:

• Solid-liquid interfaces
• XPS
• Physical adsorption
• Electrolyte
• Silica
• Surface chemical reaction
• Discrete ion effect

Fuente:

scopus