Berlin 2012 – wissenschaftliches Programm

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UP: Fachverband Umweltphysik

UP 3: Radioactivity and Soil

UP 3.3: Vortrag

Dienstag, 27. März 2012, 12:30–12:45, HFT-FT 131

Binding of Chlorinated Organic Pollutants to Soils — •Ashour Ahmed^1,2, Sergei D. Ivanov¹, Oliver Kühn¹, and Peter Leinweber² — ¹Institute of Physics, University of Rostock, Rostock, Germany — ²Institute of Land-Use, University of Rostock, Rostock, Germany

Pollutants can be adsorbed to soil constituents, taken up by plant roots and/or leached through the unsaturated zone eventually reaching the groundwater. Exposure to these pollutants can cause disruption of endocrine, reproductive, and immune systems; neurobehavioral disorders; cancers and finally death. Thus, understanding binding mechanisms in pollutant-soil complexes is of topmost importance. We studied the adsorption of Hexachlorobenzene (HCB), which is one of the most widespread pollutants in the soil, to different soil samples. These samples were characterized and classified by elemental analysis, mass spectrometry, and X-ray measurements. These investigations revealed a strong dependence of the adsorption strength on the composition of soil organic matter (SOM). In an attempt to simulate abundant SOM, we modeled it by a representative set of molecular systems containing the most interesting functional groups. SOM-HCB complexes were studied by ab initio calculations in the gas phase. The respective binding energies are in accord with the experimental results. In order to calculate the corresponding binding free energies and to study the mechanism of the binding in solution we are employing empirical force field and ab initio molecular dynamics techniques.