Project Details
Projekt
Transport of engineered inorganic nanoparticles (EINP) through soil
Applicant
Professor Dr. Hans-Jörg Vogel
Subject Area
Soil Sciences
Term
from 2011 to 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 172114680
We will explore the mechanisms of EINP transport in soil under unsaturated conditions. The ultimate goal is to predict their mobility in the subsurface based on soil properties particle characteristics and flow conditions. There is experimental evidence (first project phase) that the mobility of EINP exhibit a highly non-linear behavior in the state space defined by solution chemistry, average water content and particle properties including various coatings. The role of different interfaces (water-solid and water-air) is known to be critical but yet unclear. We will conduct column experiments at the mm-scale of single grains and micro-aggregates. The structure of water-solid and water-air interfaces for various unsaturated flow conditions will be quantified using a new nano-X-ray-CT system (UFZ). The affinity of EINP to these interfaces will be studied in separate experiments. This information will be used to model EINP transport at the scale of soil horizons based on classical filtration theory extended by a model component describing the interaction of EINP to water-air interfaces and the retention by particle straining during unsaturated flow. Moreover, remobilization of EINP in changing flow fields will be considered. All model parameters will be obtained form independent measurements without calibration. A set of transport experiments will be performed for different particles, different material structures and different flow rates. This will provide a substantial data set to explore the predictive potential of our approach.We will use metallic and oxidized particles of various types (Ag, Au, Ag2S and TiO2) with different coatings and aging status. All EINP will be provided by the project partners. After the transport experiments, EINP will also be characterized in terms of size, aggregation status and surface properties in the outflow and in the retained fractions within soil. This is done in cooperation with project partners and will provide valuable insight into the relation between particle properties and retention mechanisms, which eventually will help to improve the model parameterization.
DFG Programme
Research Units
