W. Janusz et al., The structure of the electrical double layer at the titanium dioxide ethanol solutions interface, COLL SURF A, 152(3), 1999, pp. 223-233
Citations number
37
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
Results of experiments on surface charge formation in the system monodisper
sed TiO2/water or ethanol-water solution of NaCl are presented. The investi
gations on the solid/water solution of the electrolyte proved that sodium i
on adsorption for pH < pH(pzc) is negligibly small. For NaCl concentrations
as low as 0.0001 and 0.001 mol/dm(3) and pH > pH(pzc), negative adsorption
of Cl- was observed. The above results evidence that the concentration of
the surface species, responsible for anion and cation complexity, is neglig
ibly small in the examined range. Potentiometric titrations, ion adsorption
and zeta potential measurements in monodispersed TiO2/ethanol-water and et
hanol solution of NaCl were carried out. The presence of ethanol in the sol
ution has no important effect on the acid-basic reactions of surface hydrox
ide groups in the system, but the adsorption process of background electrol
yte ions from ethanol solutions is very complex because it depends on the d
egree of solvation of both the ions and the oxide surface. The presence of
ethanol in the system only slightly decreases the zeta potential and surfac
e charge values in low ionic strength solutions. (C) 1999 Elsevier Science
B.V. All rights reserved.