Japan Geoscience Union Meeting 2019

Presentation information

[E] Oral

A (Atmospheric and Hydrospheric Sciences ) » A-GE Geological & Soil Environment

[A-GE28] Subsurface Mass Transport, Material Cycle, and Environmental Assessment

Thu. May 30, 2019 9:00 AM - 10:30 AM 301A (3F)

convener:Yuki Kojima(Department of Civil Engineering, Gifu University), Shoichiro Hamamoto(Department of Biological and Environmental Engineering, The University of Tokyo), Hirotaka Saito(Department of Ecoregion Science, Tokyo University of Agriculture and Technology), Yasushi Mori(Graduate School of Environmental and Life Science, Okayama University), Chairperson:Yuki Kojima(Gifu University), Shoichiro Hamamoto(The University of Tokyo), Yasushi Mori(Okayama University), Hirotaka Saito(Tokyo University of Agriculture and Technology)

9:25 AM - 9:40 AM

[AGE28-02] Nano-Bubble Retention in Saturated Porous Media under Different Solution Chemistry

*Shoichiro Hamamoto1, Takuya Sugimoto1, Takato Takemura2, Taku Nishimura1, Scott A Bradford3 (1.Department of Biological and Environmental Engineering, The University of Tokyo, 2.College of Humanities and Sciences, Nihon University, 3.U. S. Salinity Laboratory)

Keywords:Nano bubble, Transport, Porous media, Solution chemistry

An understanding of nano-bubble (NB) migration in porous media is needed for potential environmental applications. This research investigates factors that control the transport, retention, and release of air NBs in repacked glass beads. One-dimensional column transport studies with air NBs were conducted under different solution IS, ionic composition, and pH conditions. Collected data were simulated using a mathematical model that considered advective and dispersive transport, first-order kinetic retention, and transient release. Results were interpreted with the aid of interaction energy calculations that considered electric double layer, van der Waals, and Lewis acid-base interactions on surfaces with different amounts of nanoscale roughness. NB concentrations in the effluent were reduced with an increase in ionic strength (IS) or a decrease in pH due to a reduction in the repulsive force between the glass surface and NBs, especially when the solution contained Ca2+ as compared to Na+ and for larger NBs. NB retention on the surface was explained by ubiquitous nanoscale roughness on the glass beads that significantly lowered the energy barrier, and localized attractive charge heterogeneity and/or hydrophobic interactions.