Solubilization and photochemical degradation of polycyclic aromatic hydrocarbons in perfluorinated surfactant solutions.

摘要

This study evaluated the potential of applications of perfluorinated surfactants (PFS) in environmental engineering that take advantage of the low reactivity of perfluorinated compounds. The interaction of PFS (ammonium perfluorooctanoate and lithium perfluorooctanesulfonate) with polycyclic aromatic hydrocarbons (PAHs) was investigated to gain knowledge about the environmental behavior of PFS. The solubilization of PAHs by PFS micelles was quantified to obtain the micellar partition coefficients. Significant enhancement of PAH solubility by PFS was observed in this study.; It is shown that photolysis degraded contaminants without damaging the PFS. In addition, information on photolysis combined with hydrogen peroxide (UV/H₂O₂ process) in surfactant solutions was obtained. Photolysis experiments were conducted in aqueous solutions of PFS with and without hydrogen peroxide. Pseudo-first order rate constants were obtained and the efficacy of hydrogen peroxide was determined. The direct photolysis of PAHs depends on the nature of solubilizates and surfactants. Application of hydrogen peroxide has been shown to dramatically enhance the photolysis of PAHs in water and surfactant solutions compared to direct photolysis in this study, indicating that hydroxyl radicals may be generated at same or near sites of PAHs solubilized in the micelles. However, a smaller rate enhancement was observed in micellar solutions with respect to that in water. This result is consistent with observations by this study that more hydrogen peroxide is present in the aqueous phases than in micellar phase and that the photolysis of hydrogen peroxide is inhibited in surfactant solutions.; The recovery and reuse of PFS after photolysis has been successfully demonstrated by measuring the solubilizing ability before and after photolysis of PFS with and without hydrogen peroxide.; Photolysis was shown to be very effective treatment method for not only PAH degradation but also surfactant recovery and reuse. UV/H₂O ₂ process can be also applicable for both purposes.