title: Solubilization of polycyclic aromatic hydrocarbon mixtures in micellar nonionic surfactant solutions.
abstract: This study sought to examine the solubilization of mixtures of the polycyclic aromatic hydrocarbons (PAHs) in solutions of the nonionic surfactants: Tween 20, Tween 80, Triton X 100, Brij 35, and Brij 58. When pyrene (PYR), fluoranthene (FLA), and phenanthrene (PHE) were solubilized from two-PAH mixtures, the PAH concentrations and molar solubilization ratios deviated very little from those as found in the single-PAH systems. When these PAHs were solubilized from the three-PAH mixtures, however, not all three PAHs reached their single-PAH solubilities. When the PAHs were added sequentially to surfactant solution, the PAH added last reached its single-PAH solubility, while the concentration of other two PAHs were lowered by 14-45%. When the PAHs were added simultaneously to the surfactant solution, the composition of the solid phase influenced which PAH reached its single-PAH solubility. For solids containing equal mole fractions of all three PAHs, FLA and PHE dissolved in surfactant solution to a lesser extent than the single-PAH systems. In similar systems containing no surfactant, only FLA solubility decreased. As the mole fraction of a PAH in the solid phase increased, its solubility in the micelle phase (and in the aqueous phase) increased up to the solubility limit. Based on these studies, both PAH-PAH interactions and micelle-PAH interactions should be taken into account when predicting the concentrations of PAH mixtures in micellar surfactant solutions. This should be done because PAH-PAH interactions can influence aqueous solubility, while micelle-PAH interactions can affect the distribution of PAHs in the micellar phase, which may change as the mixture composition changes.
authors.affiliation: Naval Research Laboratory, Washington, DC 20375, USA. prak@usna.edu
authors.forename: Dianne J Luning
authors.initials: DJ
authors.lastname: Prak
authors.forename: Parmely H
authors.initials: PH
authors.lastname: Pritchard
mesh_terms: D008823:Micelles; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000737:chemistry*; D012995:Solubility; D013501:Surface-Active Agents / Q000737:chemistry*; D014873:Water Pollutants / Q000032:analysis
chemical_list: D008823:Micelles; D011084:Polycyclic Aromatic Hydrocarbons; D013501:Surface-Active Agents; D014873:Water Pollutants