University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Master / Diploma Thesis:
Eric Frank Patrick Merten
(2006):
Erstellung von Cd - und Pb - Desorptionsisothermen im konsekutiven und parallelen Ansatz.
Master / Diploma Thesis,
BOKU-Universität für Bodenkultur,
pp 49.
UB BOKU
obvsg
- Abstract:
- Desorption isotherms of cadmium and lead were determined on a heavy-metals-polluted soil collected near the former lead and zinc smelter in Arnoldstein, Austria, with batch experiments using an extraction solution adjusted to the soil. The mode and time used to shake the samples were determined in preliminary time series experiments. The desorption isotherms were determined with two different methods, whose results were compared. On the one hand they were determined by widening the solution:soil ratio (parallel approach) and on the other hand they were determined by repeatedly extracting the same soil sample with constant solution:soil ratio (consecutive approach). The desorption isotherms show atypical curve progressions. Furthermore, the desorption curves of both methods deviate significantly from each other. The results of the time series and the desorption isothermes indicate the exposure of new reactive surfaces during the extraction, which appear to be different from the active surfaces concerning amount and bond strength at the beginning of the reaction. In the area of Arnoldstein there were periods of different high immissions in the past, which caused accumulation of varying amounts of heavy metals by occlusion. Exposure of new surfaces caused by the destruction of soil particles and by the differential invasivity of the extractions resulted in alternating release and readsorption of cadmium and lead as the extraction process proceeded. This caused also difficulties in the determination of the optimal shaking time. Moreover, artefacts due to the application of two different methods of phase seperation (filtration and centrifugation) were found. Because of this results the desorption curves of this specific, industrial polluted soil are not suitable for use in rhizosphere and ionic transport models, which allow predictions about the plant roots’ uptake of nutrients and heavy metals.
- Beurteilende(r): Wenzel Walter