HR: 08:30h
AN: H21H-03    [Abstracts]
TI: Pore-scale Characterization of Organic Immiscible-Liquid Morphology in Natural Porous Media Using Synchrotron X-Ray Microtomography
AU: * Schnaar, G
EM: gschnaar@email.arizona.edu
AF: Soil, Water and Environmental Science Department, 429 Shantz Building, Tucson, AZ 85721
AU: Brusseau, M L
EM: brusseau@ag.arizona.edu
AF: Soil, Water and Environmental Science Department, 429 Shantz Building, Tucson, AZ 85721
AU: Brusseau, M L
EM: brusseau@ag.arizona.edu
AF: Hydrology and Water Resources Department, 1133 E. North Campus Drive, Tucson, AZ 85721
AB: The objective of this study was to quantitatively characterize the pore-scale morphology of organic immiscible liquid (chlorinated solvents) residing within natural porous media. Synchrotron X-ray microtomography was used to obtain high-resolution, three-dimensional images of solid and liquid phases in packed columns. The image data were processed to generate quantitative measurements of organic-liquid blob morphology. Several porous media, comprising a range of particle-size distributions, were used to evaluate the impact of porous-medium texture on blob morphology. Organic liquid blob morphology was characterized in both two-phase (water-organic liquid) and three-phase (water-organic liquid-air) systems. The sizes and shapes of the organic-liquid blobs varied greatly, ranging from small spherical singlets (as small as 0.03-mm in diameter) to large, amorphous ganglia with mean lengths of 4-5 mm. The majority of the total organic-liquid surface area and volume was associated with the largest blobs. The distribution of blob sizes was greatest for the porous medium with the broadest particle-size and pore-size distributions. A significant portion of the organic liquid in the three-phase systems was observed to exist as lenses and films in contact with air. These features were not observed in the two-phase water-organic liquid systems. Additional studies were conducted to examine changes in blob morphology and associated mass flux due to dissolution induced mass removal. The microtomography method allowed for observations of the dissolution progress of individual organic liquid blobs, as well as changes in global volume, surface area, and water-organic liquid interfacial area.
DE: 1829 Groundwater hydrology
DE: 1831 Groundwater quality
DE: 1834 Human impacts
DE: 1875 Vadose zone
SC: Hydrology [H]
MN: Fall Meeting 2005