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| Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are difficult to remove from the water environment due to their inertness to photolysis, hydrolysis, and biodegradation. In the study, the rapid decomposition of PFOS and PFOA was found in the presence of Sr-β-Bi2O3 as a photocatalyst under visible light irradiation. Compared with nano-TiO2 and direct photolysis, the photocatalysis by Sr-β-Bi2O3 can remove PFOS and PFOA more efficiently. In 1.0 h, about 72.3% of PFOS and 60.1% of PFOA ([PFOS]i = [PFOA]i = 100 μgL-1) can be removed from the aqueous solution under visible light irradiation (λ > 440 nm). The effects of temperature, pH, and initial PFOS/PFOA concentration on the photocatalytic decomposition rates were investigated. Sequentially, the intermediate products were identified as PFO (C8F17), PFHe (C6F13), PFPe (C5F11), PFBu (C4F9), PFPr (C3F7), PFHpS (C7F15SO3), and PFHeS (C6F13SO3). Based on the detection of reactive radicals, photocatalytic reduction by hydrated electron was determined as the major degradation route. The detailed defluorination pathway was also proposed. |
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| Keywords:Industrial catalysis; Perfluorooctane sulfonates; Perfluorooctanoic acid; Decomposition; Photocatalysis; Visible light irradiation |
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