Air sparging is a popular soil remediation technique that enables the removal of contaminants by diffusing air into saturated zones of soil. The removal process is, however, slow. The goal of this work is to study the effect of electromagnetic (EM) waves - with minimal heat generation - on transport mechanisms such as diffusion, in order to improve airflow or contaminant transport and expedite the cleanup process using air sparging or similar technologies. This effect is studied through an experimental setup that examines the diffusion of a nonreactive dye in water under EM waves at a range of frequencies between 50 and 200 MHz. The electric field was simulated using COMSOL Multiphysics for better 3D visualization and analysis and then validated using experimental measurements. A dielectrophoretic study was performed using the simulated electric field. Various dye flow under EM stimulation at different frequencies were compared. At 65MHz and 76 MHz, the dye flow was in the direction of the dielectrophoretic forces, which is believed to be the governing mechanism for dye transport.
This document was originally published by Electromagnetics Academy in Progress In Electromagnetics Research Symposium Proceedings, Stockholm, Sweden, Aug. 12-15, 2013. Copyright restrictions may apply.
Farid, A.; Azad, M.; Browning, J.; and Barney Smith, Elisa H.. (2013). "Electromagnetic Stimulation of Transport in Water for Geoenvironmental Applications". Progress In Electromagnetics Research Symposium Proceedings, Stockholm, Sweden, Aug. 12-15, 2013, 1843-1848.