Linear Anionic Surfactant (SDS) Transport in High Humic Volcanic Ash Soil and its Permeability

Abstract

An anionic surfactant is used in detergents. It has also been tested as a cleaner for soils contaminated with hazardous organic compounds. However, surfactants contaminate aquatic environments because they can destroy cell membranes. Surfactant movements and reactions in soils are not well understood. In this study, we performed surfactant transport and adsorption experiments in soil in order to clarify these phenomena. A linear anionic surfactant, sodium dodecyl sulfate (SDS), and a highly humic volcanic ash soil were used. SDS transport and adsorption showed characteristic phenomena. with the results indicating that SDS is adsorbed cooperatively by the humic substances in the soil. These results were completely different from those for simple anions such as nitrate and chloride. Under a critical micelle concentration, the decrease in the SDS breakthrough curve coincided with the decrease in hydraulic conductivity, demonstrating that SDS adsorption generates a decrease in hydraulic conductivity.