Mass transfer, aging and reactions at NAPL interfaces in porous media
Final Report Abstract
Transfer of pollutants across the interface between water and non aqueous phase liquids (NAPL) and the associated ageing process of the NAPL phase was studied. Batch and flow-through experiments at various biogeochemical conditions with model and real world NAPLs were conducted. Our results show that the formation of a viscous film at the NAPL/water interface could not be explained by current hypotheses such as oxidation or reduction reactions with dissolved or solid constituent of aquifers. Our data rather suggest that depletion of low molecular weight compounds such as phenols is a major driving force for ageing processes of coal tars and raw oils in water. Mass transfer experiments on multi component model NAPL-water systems containing phenols, heteroaromatic compounds and PAHs were conducted and the compounds´ leaching was successfully simulated using a numerical model based on mass balance considerations and a generalized form of Raoult’s law. Our analysis showed that consideration of the non-ideal behavior of the more polar solutes in the NAPL phase was essential for predicting the time course of leaching behavior from the NAPL phase to water.
Publications
- Compound-Specific Factors Influencing Sorption Nonlinearity in Natural Organic Matter. Environ. Sci. Technol., 2008, 42 (16), pp 5897–5903
Endo, S, Grathwohl, P. Haderlein, S.B., Schmidt, T.C.
- Characterization of Sorbent Properties of Soil Organic Matter and Carbonaceous Geosorbents Using n- Alkanes and Cycloalkanes as Molecular Probes. Environ. Sci. Technol., 2009, 43 (2), pp 393–400
Endo, S. Grathwohl, P. Haderlein, S.B., Schmidt, T.C.
