Study of the superficial properties of some metallic oxides by inverse gas chromatography and by zetametry in aqueous and organic media

Inverse gas chromatography and zeta potential techniques are used to study some of the surface properties of zinc oxide ZnO, monogal (essentially constituted by ZnO), zinc hydroxide Zn (OH)(2) and magnesium oxide MgO. The dispersive component of their surface energy, their (Lewis) acide-base characteristics and isoelectic point (IEP) in both aqueous and organic media, are determined in order to understand and predict the adhesive capacity of such oxides. We showed that the dispersive component of the surface energy gamma(S)(D) of these oxides depends on temperature T: irregularly for monogal and linearly for ZnO and Zn (OH)(2). For MgO gamma(S)(D) remains constant as a function of the temperature. It is shown that Zn (OH)(2) exhibits the highest surface acidity followed,ed respectively in decreasing acidity order by monogal, ZnO and MgO. Zeta potential measurements of the oxides in aqueous medium lead to the conclusion that MgO is more basic (IEP = 11) than the other oxides, whereas monogal is the most acidic one, in term of Bronsted acide-base concept.