Sorption properties of oxides: III. Iron oxides

Abstract

Iron oxides have been prepared by wet method using Fe(III) and Fe(II) salt solutions in the ratio 2:1 and using different alkalis for precipitation. Only NH₄OH gives a product which is mainly magnetite but noncrystalline. Sorption of alkali metal ions was studied under alkaline conditions and a series Li⁺<Na⁺<K⁺~Cs⁺ has been established for the first time. A sequence for the sorption capacities for the transition metal ions: Cu²⁺>Zn²⁺>Ni²⁺>Mn²⁺ has also been established. Sorption is quite significant even in the presence of salt solutions. It is postulated that transition metal ions are sorbed as hydrolyzed species. Sorption of Fe²⁺ and Fe³⁺ is complex.