Photochemical treatment of a mixed PAH/surfactant solution for surfactant recovery and reuse

Abstract

AbstractBecause of their hydrophobic nature, polycyclic aromatic hydrocarbons (PAHs) are generally thought to be unavailable to in situ remediation processes, and solubilization of PAHs by surfactants is usually recommended. However, mixed PAH/surfactant solutions are wastewaters that need a post‐treatment after solubilization. In this study, mixed solutions of PAH and perfluorinated surfactant (PFS) were photochemically treated with and without hydrogen peroxide (H2O2), and the subsequent recovery and reuse of surfactant solutions were demonstrated. Phenanthrene and pyrene were selected as representative PAHs and lithium perfluorooctanesulfonate (LiFOS) as a PFS. Direct photolysis (UV only) and UV/H2O2 process enhanced the PAH degradation in LiFOS solutions compared to water. Both treatment processes selectively degraded PAHs without damaging PFS, suggesting that PFS withstands photolysis. Overall, it is demonstrated that UV and UV/H2O2 processes of mixed PAH/PFS solutions are effective for surfactant recovery/reuse, as well as PAH degradation.