Adsorption sites of kaolin

The electrophoretic mobility and adsorptive properties of kaolin and kaolin pretreated with anionic and cationic materials were examined over a range of pH values. Pretreatment with anionic compounds had little effect on mobility, while adsorption of cationic species markedly reduced mobility. These results are explained by reference to the structure of kaolin, and the interdependence of adsorption properties and electrophoretic mobility are discussed.