UV/Nitrilotriacetic Acid Process as a Novel Strategy for Efficient Photoreductive Degradation of Perfluorooctanesulfonate

作者：Sun Zhuyu; Zhang Chaojie; Xing Lu; Zhou Qj; Dong Wenbo; Hoffmann Michael R

来源：Environmental Science & Technology, 2018, 52(5): 2953-2962.

DOI：10.1021/acs.est.7605912

Perfluorooctanesulfonate (PFOS) is a toxic, bioaccumulative, and highly persistent anthropogenic chemical. Hydrated electrons (e(aq)(-)) are potent nucleophiles that can effectively decompose PFOS. In previous studies, e(aq)(-) are mainly produced by photoionization of aqueous anions or aromatic compounds. In this study, we proposed a new photolytic strategy to generate e(aq)(-) and in turn decompose PFOS, which utilizes nitrilotriacetic acid (NTA) as a photosensitizer to induce water photodissociation and photo ionization, and subsequently as a scavenger of hydroxyl radical ((OH)-O-center dot) to minimize the geminate recombination between (OH)-O-center dot and e(aq)(-). The net effect is to increase the amount of e(aq)(-) available for PFOS degradation. The UV/NTA process achieved a high PFOS degradation ratio of 85.4% and a defluorination ratio of 46.8% within 10 h. A pseudo-first-order rate constant (k) of 0.27 h(-1) was obtained. The laser flash photolysis study indicates that e(aq)(-) is the dominant reactive species responsible for PFOS decomposition. The generation of eaqis greatly enhanced and its half-life is significantly prolonged in the presence of NTA. The electron spin resonance (ESR) measurement verified the photodissociation of water by detecting (OH)-O-center dot. The model compound study indicates that the acetate and amine groups are the primary reactive sites.

• 出版日期2018-3-6
• 单位同济大学