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Near-complete destruction of PFAS in aqueous film-forming foam by integrated photo-electrochemical processes

Nature Water (2024)Cite this article

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Abstract

Per- and polyfluoroalkyl substances (PFAS) are highly recalcitrant pollutants in the water environment worldwide. Aqueous film-forming foam (AFFF) used for firefighting is a major source of PFAS pollution. However, complete defluorination (that is, cleaving all C–F bonds into F− ions) of PFAS by non-thermal technology is rare. The destruction of the PFAS mixture in the complex organic matrix of AFFF is even more challenging. Here we designed and demonstrated an ultraviolet/sulfite–electrochemical oxidation (UV/S–EO) process. The tandem UV/S–EO leverages the complementary advantages of UV/S and EO modules in the PFAS transformation mechanism and the engineering process design (for example, foaming control, chemical dosage and energy consumption). At ambient temperature and pressure, the UV/S–EO realized near-complete defluorination and mineralization of most PFAS and organics in AFFF (50–5,000 times diluted, containing up to 200 mg l−1 organic fluorine and 3,764 mg l−1 organic carbon). This work highlights the integration of molecular-level insight and engineering design towards solving the major challenges of AFFF water pollution.

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Fig. 1: EO destruction and defluorination of individual PFAS.
Fig. 2: UV/S–EO treatment of selected PFAS.
Fig. 3: Evolution of detected transformation products during the UV/S–EO treatment of 25 μM PFOA.
Fig. 4: UV/S–EO treatment of AFFF.
Fig. 5: Advantages and engineering considerations of the UV/S–EO process.

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Data availability

The data that support the findings of this study are available within the paper and its Supplementary Information. Source data for all graphs are provided in this paper.

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Acknowledgements

Financial support was provided by the Strategic Environmental Research and Development Program (ER22-3184 for Y.G., Z.L., N.Y., J.L. and Y.Y.) and the National Science Foundation (CBET-2120452 for S.Y., L.E.Q.-C. and Y.Y.). We thank S. Fernando and T. Holsen at Clarkson University for providing the Ansulite AFFF sample and the assistance in non-targeted PFAS analyses.

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Authors and Affiliations

  1. Department of Civil and Environmental Engineering, Clarkson University, Potsdam, NY, USA

    Yunqiao Guan, Nanyang Yang, Shasha Yang, Luz Estefanny Quispe-Cardenas & Yang Yang

  2. Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA, USA

    Zekun Liu & Jinyong Liu

  3. Institute for a Sustainable Environment, Clarkson University, Potsdam, NY, USA

    Shasha Yang & Luz Estefanny Quispe-Cardenas

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Contributions

Y.G. conducted PFAS degradation experiments, analysed the data and drafted the paper. Z.L. conducted PFAS degradation and NMR analysis. N.Y., S.Y. and L.E.Q.-C. assisted in the liquid chromatography high-resolution tandem mass spectrometry analysis. J.L. and Y.Y. designed and supervised the research and revised the paper.

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Correspondence to Jinyong Liu or Yang Yang.

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Nature Water thanks Shilai Hao and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary information

Supplementary Texts 1–3, Tables 1–5 and Figs. 1–21.

Source data

Source Data Fig. 1

EO treatment of individual PFAS.

Source Data Fig. 2

UV/S–EO degradation and defluorination of individual PFAS.

Source Data Fig. 3

Transformation of PFOA during UV/S–EO treatment.

Source Data Fig. 4

UV/S–EO treatment of AFFF.

Source Data Fig. 5

Variation of TOC and foaming potentials during UV/S–EO treatment; energy consumption evaluation.

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Guan, Y., Liu, Z., Yang, N. et al. Near-complete destruction of PFAS in aqueous film-forming foam by integrated photo-electrochemical processes. Nat Water (2024). https://doi.org/10.1038/s44221-024-00232-7

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