A remediation technique involving surfactant foam (SF) was investigated by using a micromodel with a view toward improved contaminant displacement. A residual trichloroethylene (TCE) saturation was emplaced in an otherwise water-saturated micromodel Air flow was introduced to a surfactant solution flow (Sodium C{sub}(14-16) olefin sulfonate 2-(w)) commonly utilized in surfactant flushing to obtain the SF Conventional remediation strategies, surfactant flushing, water flooding, and gas flooding were also employed for comparison to the SF flooding The removal efficiency was quantified by directly measuring the remaining TCE blob area with an image analyzer. The micromodel visualization showed that the SF is capable of displacing a higher amount of TCE as compared to surfactant solution alone. The SF flooding removed 99 of the residual TCE, while surfactant flushing removed 41 with 25 pore volumes of the same surfactant solution. Based on micromodel visualization, the resulting enhanced removal of TCE blobs due to direct and indirect displacements, increased solubility and blob snap-off were investigated. The micromodel was also oriented vertically, and no vertical movement of the TCE was observed during SF flooding. Thus, the SF flooding achieved high TCE removal efficiency without lowering the interfacial tension to an ultralow value and causing vertical migration, which has been of particular concern in TCE removal.
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