Decomposition of Environmentally Persistent Perfluorooctanoic Acid in Water by Photochemical Approaches

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• 作者：Hisao Hori ; Etsuko Hayakawa ; Hisahiro Einaga ; Shuzo Kutsuna ; Kazuhide Koike ; Takashi Ibusuki ; Hiroshi Kiatagawa ; and Ryuichi Arakawa
• 刊名：Environmental Science & Technology
• 出版年：2004
• 出版时间：November 15, 2004
• 年：2004
• 卷：38
• 期：22
• 页码：6118 - 6124
• 全文大小：196K
• 年卷期：v.38,no.22(November 15, 2004)
• ISSN：1520-5851

文摘

The decomposition of persistent and bioaccumulativeperfluorooctanoic acid (PFOA) in water by UV-visible lightirradiation, by H₂O₂ with UV-visible light irradiation, andby a tungstic heteropolyacid photocatalyst was examined todevelop a technique to counteract stationary sources ofPFOA. Direct photolysis proceeded slowly to produce CO₂,F^-, and short-chain perfluorocarboxylic acids. Comparedto the direct photolysis, H₂O₂ was less effective in PFOAdecomposition. On the other hand, the heteropolyacidphotocatalyst led to efficient PFOA decomposition and theproduction of F^- ions and CO₂. The photocatalyst alsosuppressed the accumulation of short-chain perfluorocarboxylic acids in the reaction solution. PFOA in theconcentrations of 0.34-3.35 mM, typical of those inwastewaters after an emulsifying process in fluoropolymermanufacture, was completely decomposed by the catalystwithin 24 h of irradiation from a 200-W xenon-mercurylamp, with no accompanying catalyst degradation, permittingthe catalyst to be reused in consecutive runs. Gaschromatography/mass spectrometry (GC/MS) measurementsshowed no trace of environmentally undesirable speciessuch as CF₄, which has a very high global-warming potential.When the (initial PFOA)/(initial catalyst) molar ratio was 10:1, the turnover number for PFOA decomposition reached4.33 over 24 h of irradiation.