Polycyclic aromatic hydrocarbon surfactant solubilization

Edwards, D.A., Euthy, R.G., and Eiu, Z. Solubilization of polycyclic aromatic hydrocarbons in micellar nonionic surfactant solutions. Environ. Scl. Technol, 25(1) 127-133, 1991. 

A combined effect of natural organic matter and surfactants on the apparent solubility of polycyclic aromatic hydrocarbons (PAHs) is reported in the paper of Cho et al. (2002). Kinetic studies were conducted to compare solubilization of hydro-phobic contaminants such as naphthalene, phenanthrene, and pyrene into distilled water and aqueous solutions containing natural organic matter (NOM) and sodium dodecyl sulfate (SDS) surfactant. The results obtained after 72hr equilibration are reproduced in Fig. 8.19. The apparent solubility of the three contaminants was higher in SDS and NOM solutions than the solubility of these compounds in distilled water. When a combined SDS-NOM aqueous solution was used, the apparent solubility of naphthalene, phenanthrene, and pyrene was lower than in the NOM-aqueous solution. 

Liu, Z Laha, S. Luthy, R. G. (1991). Surfactant solubilization of polycyclic aromatic hydrocarbon compounds insoil-water suspensions. WaterScienceandTechnology, 23,475-85. 

Yeom, I T., Ghosh, M.M., and Cox, C.D. (1996). Kinetic aspects of surfactant solubilization of soil-bound polycyclic aromatic hydrocarbons. Environ. Sci. Technol., 30, 1589-1595. 

In previous studies, the solubilization of hydrophobic organic contaminants using surfactants has been shown to increase the rate of contaminant desorption from soil to water (Deitsch and Smith 1995 Yeom et al. 1995 Tiehm et al. 1997). A 3,000 mg/L solution of Triton X-100 (CMC = 140 mg/L) increased the rate of desorption of laboratory-contaminated TCE from a peat soil (Deitsch and Smith 1995). However, the solubilization effect was secondary compared to the surfactant s effect on the desorption rate coefficient. Yeom et al (1995) developed a model that satisfactorily predicted the extent of polycyclic aromatic hydrocarbon solubilization from a coal tar-contaminated soil. Only at high surfactant dosages did the model fail to accurately predict the ability of different surfactants to solubilize polycyclic aromatic hydrocarbons. It was hypothesized that mass-transfer limitations encountered by the polycyclic aromatic hydrocarbons in the soil caused the observed differences between the data and the model simulations. In another study (Tiehm et al. 1997), two nonionic surfactants, Arkopal N-300 and Saogenat T-300, increased the rate of polycyclic aromatic hydrocarbon desorption from a field-contaminated soil. The primary mechanism for the enhanced desorption of polycyclic aromatic hydrocarbons was attributed to surfactant solubilization of the polycyclic aromatic hydrocarbons. 

Zheng, Z. Obbard, J. P. (2002). Polycyclic aromatic hydrocarbon removal from soil by surfactant solubilization and Phanerochaete chrysosporium oxidation. Journal of Environmental Quality, 31, 1842-7. 

A series of related experiments investigated nonionic surfactant sorption onto soil, mechanisms of nonionic surfactant solubilization of polycyclic aromatic hydrocarbon (PAH) compounds from soil, and microbial mineralization of phenanthrene in soil-aqueous systems with nonionic surfactants. Surfactant solubilization of PAH from soil at equilibrium can be characterized with a physicochemical model by using parameters obtained from independent tests in aqueous and soil-aqueous systems. The microbial degradation of phenanthrene in soil-aqueous systems is inhibited by addition of alkyl ethoxylate, alkylphenyl ethoxylate, or sorbitan- (Tween-) type nonionic surfactants at doses that result in micellar solubilization of phenanthrene from soil. Available data suggest that the inhibitory effect on phenanthrene biodegradation is reversible and not a specific, toxic effect. 

Edwards D.A., Luthy R.G. and Liu Z., Solubilization of Polycyclic Aromatic Hydrocarbons in Micellar Nonionic Surfactant Solutions . Environ. Sci. Technol. 25, 127-133.(1991)... 

Polycyclic aromatic hydrocarbons (PAHs), representative HOCs, are very hydro-phobic and have quite low aqueous solubUity. The solubilization/desorption and partitioning of PAHs in soil-water systems have been extensively studied using solubUity-enhancing solutions such as surfactants and cosolvents to achieve effective removal of PAHs from contaminated sites. Recently, a number of laboratory studies on the electrokinetic removal of PAHs have appeared, evaluating the effect of enhancing solution and electrokinetic variables. The field remains underresearched in comparison with metal removal studies. 

Li JL, Chen BH (2002). Solubilization of model polycyclic aromatic hydrocarbons by nonionic surfactants. Chemical Engineering Science 57(14) 2825-2835. 

Zhu L, Feng S (2003). Synergistic solubilization of polycyclic aromatic hydrocarbons by mixed anionic-nonionic surfactants. Chemosphere 53(5) 459-467. 

Cosolvent-enhanced electrokinetic remediation of chlorinated pesticides has yet to be explored. Few studies have shown enhancements in the transport of polycyclic aromatic hydrocarbons (PAHs) when cosolvents were used (Maturi and Reddy, 2008 Reddy and Saichek, 2003). The potential success of cosolvents depends on their ability to mobilize the HOCs and to increase the EOF. It was shown that 10% n-butylamine generated the greatest EOF, followed by 20% n-butylamine and water (Maturi and Reddy, 2008). The sorption of solvents to the soil matrix may not be as high as the surfactants, which cause a better solubilization with the same amount of electro-osmotic transport. 

It is well known that polycyclic aromatic hydrocarbons (PAHs) can be solubilized in aqueous solutions by micelle forming surfactants. As pointed out in our previous paper, these aqueous micellar conditions can be utilized in generating PAH-specific light emissions by electrochemical means at the rotating oxide-covered aluminum electrode. Because the aqueous micellar solutions are also well suited for chromatographic analysis of PAHs, the analytical feasibility experiments of the flow detector were carried out by utilizing the PAH-induced electroluminescence with Brij-35 and 9,10-diphenylanthracene (9,10-DPA) as the... 

It is of particular interest to be able to correlate solubility and partitioning with the molecular stmcture of the surfactant and solute. Likes dissolve like is a well-wom plirase that appears applicable, as we see in microemulsion fonnation where reverse micelles solubilize water and nonnal micelles solubilize hydrocarbons. Surfactant interactions, geometrical factors and solute loading produce limitations, however. There appear to be no universal models for solubilization that are readily available and that rest on molecular stmcture. Correlations of homologous solutes in various micellar solutions have been reviewed by Nagarajan [52]. Some examples of solubilization, such as for polycyclic aromatics in dodecyl sulphonate micelles, are driven by hydrophobic... 

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