HYDROXYLAMINE EXTRACTION OF TRACE-METALS IN SOILS - KINETIC ASPECTS

Acidified hydroxylamine is one of the chemical reagents of sequential extraction procedures, used to determine trace elements bound to iron and manganese hydroxides. A study of the hydroxylamine reactivity of cadmium, lead and copper from two heavily polluted soil samples was performed including time aspects. An attempt was first made to estimate the effect of acidity without using acidified hydroxylamine, which allows us to conclude that the non-selectivity of this reagent is due to the use of an acid. When studying time aspects of the extraction of trace elements by hydroxylamine, no evidence of cation transfer phenomena from one compartment onto the others emerged. However, kinetic modelling with simple assumptions indicates that transfer may be involved during treatment with acidified hydroxylamine without its detection from the shape of the time curves.