par Dumont, Freddy 
;Verbeiren, Paul ;Buess Herman, Claudine
Référence Colloids and surfaces. A, Physicochemical and engineering aspects, 154, page (1-8)
Publication Publié, 1999
;Verbeiren, Paul ;Buess Herman, Claudine Référence Colloids and surfaces. A, Physicochemical and engineering aspects, 154, page (1-8)
Publication Publié, 1999
Article révisé par les pairs
| Résumé : | The stability of pyrogenic tungsten trioxide hydrosols is studied in the presence of various monovalent cations between pH 2 and 12. The hydrosol critical coagulation concentrations (c*) are determined by extrapolation of the experimental logW-logc curves up to logW=0. The c* of K+, Rb+ and Cs+ slightly increase with the pH of the solution while the c* of Li+ presents a pronounced maximum at pH 4.5. A less marked maximum is also observed at the same pH in the presence of Na+. The corresponding ionic adsorption sequence at the water-WO3 interface deduced from these experimental data is Cs+>Rb+>K+>Na+>Li+ in the pH domain under investigation. This overall behavior is successfully explained by the model proposed by Gierst who has generalized the Gurney concept describing the ion-ion interactions in solution to the ion-surface interactions. The results reported in this work are also compared with those obtained previously for other oxides; they confirm the validity and the generality of the conclusions already drawn concerning the ionic adsorption sequences at the oxide-water interface. Copyright (C) 1999 Elsevier Science B.V. |
