Hydraulic Properties of Porous Media Saturated with Nanoparticle-Stabilized Air-Water Foam

The foam generated by the mixture of air and water has a much higher viscosity and lower mobility than those of pure water or gas that constitutes the air-water foam. The possibility of using the air-water foam as a ���ow barrier for the purpose of groundwater and soil remediation is explored in this paper. A nanoparticle-stabilized air-water foam was fabricated by vigorously stirring the nano-���uid in pressurized condition. The foam bubble size distribution was analyzed with a microscope. The viscosities of foams generated with the solutions with several nanoparticle concentrations were measured as a function of time. The breakthrough pressure of foam-saturated micro���uidicchipsandsandcolumnswereobtained. Thehydraulicconductivityofafoam-���lledsand column was measured after foam breakthrough. The results show that: (1) bubble coalescence and theOstwaldripeningarebelievedtobethereasonofbubblesizedistributionchange;(2)theviscosity of nanoparticle-stabilized foam and the breakthrough pressures decreased with time once the foam was generated; (3) the hydraulic conductivity of the foam-���lled sand column was almost two orders of magnitude lower than that of a water-saturated sand column even after the foam-breakthrough. Based on the results in this study, the nanoparticle-stabilized air-water foam could be injected into contaminated soils to generate vertical barriers for temporary hydraulic conductivity reduction.This study is funded by Jang's start-up fund provided by Arizona State University. Jaewon Jang has not received any support to publish in open access