ABSTRACT:

Surfactant-aided flushing has been proposed as an alternative for the expensive and time consuming pump and treat technology in the remediation of contaminated soil and groundwater. Injected surfactants can effectively solubilize contaminants sorbed to the soil matrix or nonaqueous phase liquids (NAPLs) in residual saturation. Focusing on the remediation of the BTEX among subsurface contaminants, this paper studies the surfactant-enhanced desorption technique. Nonionic surfactant (Triton X-100 and Tween 20) and anionic surfactant (SDS) were used as desorbing solutions for extracting organic compound sorbed on soils. Sorption characteristics of soils and organic compounds were analyzed. Desorption tests were performed by successive reverse isotherm (SRI) tests to select effective surfactants. As a result of the sorption isotherm tests, a log-log linear relation was obtained between the linear-partition coefficient, Kp, and the octanol-water partition coefficient, Kow, of each organic compound.

INTRODUCTION

In Korea hazardous substances produced from industrial sectors have caused serious environmental problems and threatened ecological systems dating back to the early 1960''s. Soils and groundwater exposed to the variety of chemicals and chemical wastes are frequently and heavily contaminated and difficult to be treated and recovered back to normal conditions. Laboratory experiments were performed on soils with low concentrations of contaminants, which are the most difficult to remove, in which most of the contaminant was assumed to be sorbed onto the soil particles or captured in the diffuse double layers and not held in to the free pore water. Jafvert et al.(1994) discussed the efficiency of surfactant solutions (Triton X-100, Tween 20, SDS) to enhance the remediation of non-polar compounds. Valsaraj et al. (1988) reported the utilization of micellar solution of SDS to remove pollutants such as benzene, toluene. Sorption caracteristics of Nanji-do soils (97-soil) and organic compounds such as BTEX are studied with sorption equilibrium and isotherm tests.

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