ABSTRACT
Adsorption properties of alumina, silica, and iron oxides have been known for a long time, and the processes taking place have been often described in terms of ion exchange. The tendency of the elements in the IVB subgroups to form positive ions increases with increasing atomic weight. Generally speaking the oxides of the group IV elements are obtained by adding an excess of base to solutions of their salts. Hydrous stannic oxide is prepared by the acidification of sodium stannate solution or by the reaction of nitric acid with tin metal. Hydrous titanium oxide is prepared by mixing titanyl oxalate or titanium (IV) chloride solutions with sodium hydroxide. Hydrous thorium oxide is obtained by mixing different proportions of thorium nitrate with bases. It is evident that the ion exchange capacity, as with other hydrous oxides, depends on the number of hydroxyl groups on the surface of the hydrous zirconia.
