The Isoelectric Points of Solid Oxides, Solid Hydroxides, and Aqueous Hydroxo Complex Systems

摘要: Solid oxides in aqueous suspension are generally electrically charged as may be observed most directly in electrophoresis experiments. The chargehas long been attributed to one of two apparently indistinguish-able mechanisms (5-7, 36, 56, 81, 87, 129):(a) am-photeric dissociation of surface MOH groups; and (b) adsorption of metal hydroxo complexes derived from the hydrolysis products of material dissolved from the solid, ie, from amphoteric dissociation of Mz+(OH) 2-(aq).