oa Agrochemophysica - Studies on zinc in selected Orange Free State soils : V : mechanisms for the reaction of zinc with iron and aluminium oxides

Volume 2, Issue 3
  • ISSN : 0302-7112



Studies on the precipitation of Zn at varying pH values indicated that the presence of Fe and A1 cations in solution markedly lowered the pH at which precipitation of Zn occurred. Mn in solution had no effect. Various oxides of Fe and Al, in the solid phase, sorbed Zn in an analogous manner, the sorbing capacity being a function of pH and the amount of phosphate ions adsorbed by the oxides. In the absence of phosphate, the oxides in aqueous suspension commenced to sorb Zn at approximately pH 5.0. Thereafter the amount sorbed increased progressively with rising pH. The sorption reaction is probably associated with surface OH-groups, and is specific for Zn in that calcium, magnesium, ammonium and potassium ions did not interfere. Ammonium acetate solution or a weakly-acidic cation resin suppressed the sorption markedly. In the presence of phosphate ions Zn sorption in ammonium acetate medium commenced at approximately pH 5.25 and increased progressively as the pH rose. The ratio of Zn sorbed to phosphate sorbed at a given pH was reasonably constant for the different Fe and Al oxides.

Loading full text...

Full text loading...


Article metrics loading...


This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error