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

Sun, Zhuyu and Zhang, Chaojie and Xing, Lu and Zhou, Qi and Dong, Wenbo and Hoffmann, Michael R. (2018) UV/Nitrilotriacetic Acid Process as a Novel Strategy for Efficient Photoreductive Degradation of Perfluorooctanesulfonate. Environmental Science and Technology, 52 (5). pp. 2953-2962. ISSN 0013-936X. http://resolver.caltech.edu/CaltechAUTHORS:20180411-135405264

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Abstract

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 photoionization, and subsequently as a scavenger of hydroxyl radical (•OH) to minimize the geminate recombination between •OH 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 e_(aq)^– is 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. The model compound study indicates that the acetate and amine groups are the primary reactive sites.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/acs.est.7b05912DOIArticle
ORCID:
AuthorORCID
Zhang, Chaojie0000-0003-3108-8271
Hoffmann, Michael R.0000-0002-0432-6564
Additional Information:© 2018 American Chemical Society. Received: November 18, 2017. Revised: January 29, 2018. Accepted: February 2, 2018. Published: February 3, 2018. The authors greatly thank Dr. Jiahui Yang from Bruker (Beijing) Scientific Technology Co., Ltd., for her kind assistance on the ESR result analysis. The authors also gratefully acknowledge Prof. Side Yao and Dr. Huijie Shi for their valuable comments on the discussion. This study has been supported by the National Natural Science Foundation of China (Project No. 21677109) and the State Key Laboratory of Pollution Control and Resource Reuse Foundation (No. PCRRT16001). The authors declare no competing financial interest.
Funders:
Funding AgencyGrant Number
National Natural Science Foundation of China21677109
State Key Laboratory of Pollution Control and Resource Reuse FoundationPCRRT16001
Record Number:CaltechAUTHORS:20180411-135405264
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180411-135405264
Official Citation:UV/Nitrilotriacetic Acid Process as a Novel Strategy for Efficient Photoreductive Degradation of Perfluorooctanesulfonate Zhuyu Sun, Chaojie Zhang, Lu Xing, Qi Zhou, Wenbo Dong, and Michael R. Hoffmann Environmental Science & Technology 2018 52 (5), 2953-2962 DOI: 10.1021/acs.est.7b05912
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85764
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:11 Apr 2018 21:55
Last Modified:11 Apr 2018 21:55

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