Sorption and transport studies of cetyl trimethylammonium bromide (CTAB) and Triton X-100 in clayey soil

Abstract

Surfactants are soil washing agents and facilitators for subsurface remediation of hydrocarbon spills. It is important to understand the sorption and transport behavior of surfactants for enhanced soil remediation. The adsorption and desorption isotherms of cetyl trimethylammonium bromide (CTAB) and Triton X-100 with sand and kaolinite have been quantified. Kaolinite clay had the highest sorption capacity compared to blasting sand. Transport parameters such as diffusion coefficient (D) and retardation factor (R) of the above mentioned surfactant solutions were determined in clayey soils (82.5% sand and 17.5% kaolinite mixture) with near zero and 0.1 g/L ionic strength. NaCl was used as the electrolyte solution. Convection-Diffusion equation was used to model the breakthrough curves of the surfactants. Bromide ion was chosen as the tracer material in order to characterize the column. CTAB and Triton X-100 were used to flush the perchloroethylene (PCE) contaminated soil. The effectiveness of CTAB and Triton X-100 in flushing the PCE from the contaminated soil was quantified.