HR: 15:10h
AN: H43J-07    [Abstracts]
TI: Imaging and Modeling of Colloid Retention Processes in Unsaturated Pore Experiments
AU: * Lazouskaya, V
EM: volha@udel.edu
AF: Department of Plant and Soil Sciences, University of Delaware, 152 Townsend Hall, Newark, DE 19716, United States
AU: Shi, X
EM: graceshi@udel.edu
AF: Department of Mechanical Engineering, University of Delaware, 126 Spencer Lab., Newark, DE 19716, United States
AU: Wang, L
EM: lwang@udel.Edu
AF: Department of Mechanical Engineering, University of Delaware, 126 Spencer Lab., Newark, DE 19716, United States
AU: Jin, Y
EM: yjin@udel.edu
AF: Department of Plant and Soil Sciences, University of Delaware, 152 Townsend Hall, Newark, DE 19716, United States
AB: Colloid transport in natural porous media (soil) is an important environmental concern due to effects and outcomes of such processes as colloid-facilitated transport of contaminants, transport of bio-colloids and nano- sized materials, and bacterial remediation. Retention of colloids in saturated porous media is mostly associated with retention of colloids at solid-water interface (SWI) and straining. In unsaturated porous media, colloids may be additionally retained at air-water interface (AWI) and contact line. While colloid transport in saturated porous media has achieved better understanding and theoretical prediction, colloid transport in unsaturated porous media poses more uncertainties mostly associated with colloid retention on AWI and contact line. Additionally, dynamic nature of natural soil processes indicates the importance of hydrodynamic conditions, which have to be accounted for in prediction of colloid transport. The objective of the current work is to provide insight into the relative importance of retention forces (colloid and hydrodynamic forces) and retention sites (AWI and contact line) of colloids at the interface- and pore-scale through combined experimental and numerical approaches. These include visualization of colloid behavior employing a micro-fluid channel and a confocal microscope, performing an estimate of colloid forces governing colloid interfacial interactions and retention, and numerical simulation of the flow field and colloid retention in the channel using the Lattice-Boltzmann method (LBM). Coupling of colloid and hydrodynamic forces in natural media presents a challenge, but it can be attempted in model systems such as presented in the current study. Despite the ideal nature of both colloids and porous media some important results on the role of colloid interfacial behavior in colloid transport can be inferred. Expanding these results to larger scales would be the next step needed in the future.
DE: 1009 Geochemical modeling (3610, 8410)
DE: 1828 Groundwater hydraulics
DE: 1832 Groundwater transport
DE: 1847 Modeling
SC: Hydrology [H]
MN: 2007 Fall Meeting