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Photochemical transformation of perfluoroalkyl acid precursors in water using engineered nanomaterials

Dai, Yunrong and Guo, Xingxing and Wang, Siyu and Yin, Lifeng and Hoffmann, Michael R. (2020) Photochemical transformation of perfluoroalkyl acid precursors in water using engineered nanomaterials. Water Research, 181 . Art. No. 115964. ISSN 0043-1354.

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The production of perfluoroalkyl acids (PFAAs) has been phased out over recent decades; however, no significant decline in their environmental concentrations has been observed. This is partly due to the photochemical decomposition of PFAAs precursors (PrePFAAs) which remain in extensive use. The decomposition of PrePFAAs may be accelerated by the light-activated engineered nanomaterials (ENMs) in water. In light of this hypothesis, we investigated the photochemical transformation of three PrePFAAs, which are 8:2 fluorotelomer sulfonic acid (8:2 FTSA), 8:2 fluorotelomer alcohol (8:2 FTOH), and 2-(N-ethylperfluorooctane-1-sulfonamido ethyl] phosphate (SAmPAP), in the presence of six ENMs under simulated sunlight irradiation. The transformation rates of 8:2 FTSA and 8:2 FTOH were increased by 2–6 times when in the presence of six ENMs. However, most of ENMs appeared to inhibit the decomposition of SAmPAP. The transformation rates of PrePFAAs were found to depend on the yield of reactive oxygen species generated by ENMs, but the rates were also related to compound photo-stability, adsorption to surfaces, and photo-shielding effects. The PrePFAAs are transformed to perfluorooctanoic acid (PFOA) or/and perfluorooctane sulfonate (PFOS) with higher toxicity and longer half-life, PFOA or PFOS and a few PFAAs having shorter carbon chain lengths. Higher concentrations of the PFAAs photodegradation products were observed in the presence of most of the ENMs.

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Hoffmann, Michael R.0000-0001-6495-1946
Additional Information:© 2020 Elsevier Ltd. Received 20 December 2019, Revised 14 May 2020, Accepted 19 May 2020, Available online 20 May 2020. This work was financially supported by the National Key R&D Program of China (2018YFC1800400), the National Natural Science Foundation of China (Project 21777009 and 21407138), the Beijing Municipal Natural Science Foundation (8182031), and the Fundamental Research Funds for the Central Universities of China (649911019). The authors would like to thank Engineer Wang from Shiyanjia Lab ( for the EPR analysis. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Funding AgencyGrant Number
National Key Research and Development Program of China2018YFC1800400
National Natural Science Foundation of China21777009
National Natural Science Foundation of China21407138
Beijing Municipal Natural Science Foundation8182031
Fundamental Research Funds for the Central Universities of China649911019
Subject Keywords:PFAAs precursors; Engineered nanoparticles; Photochemical transformation; Reactive oxygen species; PFOS; PFOA
Record Number:CaltechAUTHORS:20200521-073912870
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Official Citation:Yunrong Dai, Xingxing Guo, Siyu Wang, Lifeng Yin, Michael R. Hoffmann, Photochemical transformation of perfluoroalkyl acid precursors in water using engineered nanomaterials, Water Research, Volume 181, 2020, 115964, ISSN 0043-1354, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:103373
Deposited By: Tony Diaz
Deposited On:21 May 2020 16:04
Last Modified:02 Jun 2020 15:56

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