Solubilization with Tween-type surfactant

Ongoing research is investigating mechanisms of nonionic surfactant sorption onto soil, nonionic surfactant solubilization of hydrophobic organic compounds (HOCs) from soil, and microbial degradation of HOCs in soil-aqueous systems with nonionic surfactants. The equilibrium solubilization of HOC from soil can be described by a physicochemical model with parameters obtained from independent experiments. The microbial degradation of phenanthrene in soil-aqueous systems is inhibited by addition of alkyl ethoxylate, alkylphenyl ethoxylate, and Tween-type surfactants at doses that result in micellization and solubilization of phenanthrene from soil. 

The surfactant system AOT/TWEEN 80 removed 99.4% of residual hexadecane from glass beads in 4.7 pore volumes with a total of 49.6% recovered as free phase, 31.1% recovered as micellarly solubilized, and 18.7% recovered as microemulsified in the middle phase. These results demonstrate the potential efficiency of supersolubilization (i.e., enhanced solubilization as the type I-III boundary is approached), and mobilization (even if just into the type III system but not yet optimal) in expediting extraction of hydrophobic NAPLs. 

Guerin and Jones (29) reported that the use of various Tween-type nonionic surfactants in aqueous media solubilized phenanthrene to different degrees and enhanced phenanthrene utilization. The order of enhancement did not correlate directly with increased solubility, a result suggesting physiological as well as physicochemical effects of surfactants. However, Aiba et al. (37) and Mimura et al. (50) observed that the growth rates of certain yeast strains actually decreased in the presence of artificial surfactants, presumably by in-... 

Zhong et al. (2003) studied the apparent solubility of trichloroethylene in aqueous solutions, where the experimental variables were surfactant type and cosolvent concentration. The surfactants used in the experiment were sodium dihexyl sulfo-succinte (MA-80), sodium dodecyl sulfate (SDS), polyoxyethylene 20 (POE 20), sorbitan monooleate (Tween 80), and a mixture of Surfonic- PE2597 and Witconol-NPIOO. Isopropanol was used as the alcohol cosolvent. Eigure 8.20 shows the results of a batch experiment studying the effects of type and concentration of surfactant on solubilization of trichloroethylene in aqueous solutions. A correlation between surfactant chain length and solubilization rate may explain this behavior. However, the solubilization rate constants decrease with surfactant concentration. Addition of the cosolvent isopropanol to MA-80 increased the solubility of isopropanol at each surfactant concentration but did not demonstrate any particular trend in solubilization rate of isopropanol for the other surfactants tested. In the case of anionic surfactants (MA-80 and SDS), the solubility and solubilization rate increase with increasing electrolyte concentration for all surfactant concentrations. 

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