The effect of surfactants on the distribution of organic compounds in the soil solid/water system.
The efficiency of soil remediation by surfactant washing was evaluated via the measured distribution coefficients of a number of nonpolar compounds in several soil-water mixtures. The studied compounds (contaminants) are BTEX (benzene, toluene, ethylbenzene, and p-xylene) and three chlorinated pesticides (lindane, alpha-BHC, and heptachlor epoxide), which span several orders of magnitude in water solubility (S(w)). A peat, and two natural soils were used that comprise a wide range in soil organic matter (SOM) content. The surfactants tested included cationic, anionic and nonionic types, with concentrations up to five to six times the critical micelle concentration (CMC). The K(d)(*)/K(d), values were used to evaluate the remediation efficiency under various operation conditions. For relatively water soluble BTEX compounds, the surfactant adsorption on the soil surface is the deciding factor on contaminant desorption from soil. For the less-soluble pesticides, surfactant micelles in solution influence the contaminant desorption more. The contaminants partitioning to SOM or adsorbed surfactants lowers the desorption efficiency. Anionic surfactants are found to be a better choice on soil remediation because they do not form admicelle on soil surface that enhances the SOM content. Cationic surfactant, which adsorb onto soil surfaces, leads to poor remediation efficiency. An improper selection of surfactant would result in inefficiency in soil remediation by surfactant washing.
Lee
Jiunn-Fwu
JF
Graduate Institute of Environmental Engineering, National Central University, Chung-Li 320,Taiwan. jflee@ncuen.ncu.edu.tw
Hsu
Ming-Hung
MH
Chao
Huan-Ping
HP
Huang
Hui-Chen
HC
Wang
Shun-Ping
SP
D000042:Absorption; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002849:Chromatography, Gas; D004787:Environmental Pollution / Q000032:analysis*; D007700:Kinetics; D008823:Micelles; D009930:Organic Chemicals / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D013501:Surface-Active Agents / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000032:analysis*; D014881:Water Supply
D008823:Micelles; D009930:Organic Chemicals; D012989:Soil Pollutants; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical