title: Evaporative mass transfer behavior of a complex immiscible liquid.
abstract: A series of laboratory experiments was conducted with a multiple-component immiscible liquid, collected from the Picillo Farm Superfund Site in Rhode Island, to examine liquid-vapor mass-transfer behavior. The immiscible liquid, which comprises solvents, oils, pesticides, PCBs, paint sludges, explosives, and other compounds, was characterized using gas chromatography and gas chromatography/mass spectrometry to determine mole fractions of selected constituents. Batch experiments were conducted to evaluate equilibrium phase-partitioning behavior. Two sets of air-stripping column studies were conducted to examine the mass-transfer dynamics of five selected target compounds present in the immiscible-liquid mixture. One set of column experiments was designed to represent a system with free-phase immiscible liquid present; the other was designed to represent a system with a residual phase of immiscible liquid. Initial elution behavior of all target components generally appeared to be ideal for both systems, as the initial vapor-phase concentrations were similar to vapor-phase concentrations measured for the batch experiment and those estimated using Raoult's law (incorporating the immiscible-liquid composition data). Later-stage removal of 1,2-dichlorobenzene appeared to be rate limited for the columns containing free-phase immiscible liquid and no porous medium. Conversely, evaporative mass transfer appeared to be ideal throughout the experiment conducted with immiscible liquid distributed relatively uniformly as a residual phase within a sandy porous medium.
authors.affiliation: Department of Soil, Water, and Environmental Science, The University of Arizona, Tucson, AZ 85721, United States.
authors.forename: Colleen M
authors.initials: CM
authors.lastname: McColl
authors.forename: Gwynn R
authors.initials: GR
authors.lastname: Johnson
authors.forename: Mark L
authors.initials: ML
authors.lastname: Brusseau
mesh_terms: D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry*; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D014872:Water Movements
chemical_list: D012989:Soil Pollutants; D012997:Solvents