Videomicroscopy study of behavior of toluene in wet and dry heterogeneous porous media
Nguyen, Hung Manh
Miller, Clarence A.
Master of Science
A novel bead-pack micromodel has been developed to observe directly with videomicroscopy movement and distribution of toluene in the subsurface, including effects of water infiltration, variations in the water table, and alcohol-water flushing. If the medium was initially partially water-saturated, toluene spread downward along air-water interfaces, leaving behind very low residual saturation. It did not penetrate low-permeable strata that were water-saturated. If the medium was initially dry, toluene saturated only a small area where it was injected. Water infiltration displaced such toluene downward, ultimately trapping it as ganglia. Subsequent water drainage exposed some ganglia to air, allowing toluene to spread downward. Other ganglia in regions of low permeability remained trapped. Limited upward displacement of toluene occurred with the raising of the water table. However, the toluene was eventually trapped. Enhanced solubilization and mobilization of toluene were observed with a flushing mixture of isopropanol and water (50/50).
Chemical engineering; Environmental science