Transformation behaviour of different platinum compounds in a clay-like humic soil: speciation investigations

Synthetic platinum compounds with different oxidation stages and a platinum containing tunnel dust, used as a natural sample, were added to a clay-like humic soil. Possible chemical and physical interactions with the soil were investigated. Oxidation of finely dispersed metallic platinum in the soil was studied by eluting platinum species with different polar solvents and complexing agents. Due to its ultrafine dispersion and nanocrystalline particle size, the platinum present in the tunnel dust was oxidised in the soil to a higher degree than the model compound platinum black. K2PtCl4 and Na2PtCl6∗ 6H2O showed strong adsorption in the soil by recomplexation into almost insoluble species. Differences in the transformation reactions between native and artificial platinum compounds are described.