EFFECT OF ANIONIC AND NONIONIC SURFACTANTS ON SORPTION AND MICELLAR SOLUBILIZATION OF MONOCYCLIC AROMATIC-COMPOUNDS

The effect of anionic and nonionic surfactants on the sorption and mic ellar solubilization of monocyclic aromatic compounds in soil-free and soil-water systems was investigated at 25 degrees C to examine the fe asibility of in situ remediation. Benzene, chlorobenzene and styrene ( BCS) were selected as the target compounds due to their suspected carc inogenic and mutagenic properties. Sodium dodecyl sulfate (SDS) and Tr iton X-100 were used to represent the anionic and nonionic surfactants , respectively. The addition of Triton X-100 had little effect on the micellar solubilization of BCS. However, the solubilization of aromati c compounds increased significantly with the increase of SDS concentra tion. A 20% to 43% enhancement of the solubilization in SDS-amended sy stems was demonstrated. The adsorption isotherms of BCS with Triton X- 100 can conveniently be fitted by Langmuirian expression. However, mul tilayer adsorption of chlorobenzene and styrene was observed in SDS-am ended systems. The values of maximum adsorption capacity ranged from 3 23 to 736 mu g/g. Also, the effect of Triton X-100 on maximum adsorpti on capacity was greater than that of SDS. Moreover, a correlation betw een the maximum sorption capacity and partition coefficient was establ ished. The results of this study demonstrate that surfactants can be e ffectively used as chemical amendments to minimize the volatilities of monocyclic aromatic compounds and enhance sorption and solubilization in soil environments contaminated by proper selection of surfactant t ype and concentration. Copyright (C) 1996 IAWQ.