Anomalous temperature behavior in clay swelling due to ion-ion correlations

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

We show, experimentally and theoretically, that swelling of both natural and refined clays has an anomalous temperature behavior depending on counterion valency. In an aqueous clay dispersion dominated by monovalent counterions the swelling pressure increases with temperature as expected from entropic arguments. In a clay with predominantly divalent counterions, the opposite behavior is found. The explanation is due to the fact that ion-ion correlations increase with temperature. Ion-ion correlations are important at strong electrostatic coupling and in an aqueous solution the dielectric permittivity, ϵr, drops with increased temperature, T, in such a way that the product ϵrT also decreases. Thus, the net effect is an increased coupling.

Detaljer

Författare
Enheter & grupper
Externa organisationer
  • Clay Technology AB
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Materialkemi
Originalspråkengelska
Artikelnummer38002
TidskriftEurophysics Letters
Volym114
Utgåva nummer3
StatusPublished - 2016 maj 1
PublikationskategoriForskning
Peer review utfördJa