PAH degradation by UV/H2O2 in perfluorinated surfactant solutions

Polycyclic aromatic hydrocarbons (PAHs) solubilized in perfluorinated surfactant (PFS) solutions were degraded by direct photolysis and UV/H2O2 process. The subsequent recovery and reuse of these surfactant solutions were also demonstrated. Phenanthrene and pyrene were selected as representative PAHs and an anionic PFS; ammonium perfluorooctanoate (APFO) was used. In our experiments, micellar APFO solutions retarded the phenanthrene photolysis and enhanced the pyrene photolysis. The results indicate that the photochemical reactivity of compound in micelles is strongly dependent on specific properties of the solubilizate, possibly due to the different excited state behaviors of compound. UV/H2O2 process exhibits a greatly enhanced rate of PAH photolysis in both water and APFO compared to direct photolysis, indicating that hydroxyl radicals may be generated or penetrated at the sites of PAHs solubilized in the micelles. Additionally, a smaller rate enhancement by UV/H2O2 in micelles than in water suggests that micelles provide some degree of protection from hydroxyl radical attack. The possibility of recovery and reuse of PFS has been demonstrated by measuring the solubilizing capacity of APFO after direct photolysis and UV/H2O2 process. Overall, this study demonstrates UV/H2O2 process can be an effective treatment method for not only PAH degradation but also surfactant recovery and reuse.