HR: 17:30h
AN: H54C-06    [Abstracts]
TI: Dynamic Retention and Release of Nanoparticles in Unsaturated Porous Media During Multiple Drying/Wetting Cycles
AU: * Chen, L
EM: lxchen@ou.edu
AF: University of Oklahoma, 202 West Boyd St., Room 334, Norman, OK 73019, United States
AU: Hoggan, J L
EM: bromothymo@yahoo.com
AF: University of Oklahoma, 202 West Boyd St., Room 334, Norman, OK 73019, United States
AU: Sabatini, D A
EM: sabatini@ou.edu
AF: University of Oklahoma, 202 West Boyd St., Room 334, Norman, OK 73019, United States
AU: Kibbey, T C
EM: kibbey@ou.edu
AF: University of Oklahoma, 202 West Boyd St., Room 334, Norman, OK 73019, United States
AB: To better understand the transport of nanomaterials in the vadose zone, a series of experiments were conducted to study the retention and release of nanomaterials in unsaturated porous media during drainage and imbibition. The research makes use of a custom-designed membrane-based automatic system which allows the continuous real-time measurement of nanomaterials retained by unsaturated porous media during multiple drainages. As nanomaterials are retained in the porous media during drainage, their concentration in the pore solution decreases. For the experiments to be discussed, the concentration decrease of nanomaterials in the pore solution was tracked during multiple drainages, along with the simultaneous tracking of porous media capillary pressure and saturation. A continuous mass balance was used to calculate the mass of nanomaterials retained as a function of saturation. The release and re-retention of previously retained nanomaterials has been investigated through a series of wetting/drying cycles with changing nanomaterial concentrations. The air-water interfacial area formed during each drainage of multiple wetting/drying cycles was measured as a function of saturation to investigate the role of the air-water interface, and to elucidate possible mechanisms governing the unsaturated transport of nanoparticles. Manufactured nanoparticles selected for this study included tin oxide (SnO2), titanium dioxide (TiO2) and polystyrene latex. The dependence of retention/release on nanoparticle properties will be discussed.
DE: 1831 Groundwater quality
DE: 1832 Groundwater transport
DE: 1847 Modeling
DE: 1875 Vadose zone
SC: Hydrology [H]
MN: 2007 Fall Meeting