Foam-Assisted Delivery of Nanoscale Zero Valent Iron in Porous Media

Abstract

AbstractFoam is potentially a promising vehicle to deliver nanoparticles for vadose-zone remediation because foam can overcome the intrinsic problems associated with solution-based delivery, such as preferential flow and contaminant mobilization and spreading. In this work, the feasibility of using foam to deliver nanoscale zero valent iron (nZVI) in unsaturated porous media was investigated. Foam generated using the surfactant sodium lauryl ether sulfate (SLES) showed excellent ability to carry nZVI. SLES and nZVI concentrations in the foaming solutions did not affect the percentages of nZVI concentrations in foam relative to nZVI concentrations in the solutions. When foams carrying nZVI were injected through the unsaturated columns, the fractions of nZVI exiting the column were much higher than those when nZVI was injected with liquid. The enhanced nZVI transport implies that foam delivery could significantly increase the radius of influence of injected nZVI. The type and concentrations of surfactants a...