Investigating Potential PFAS Emissions from Initial Electrolyzer Operation

Abstract

The fluoropolymers used in proton exchange membrane (PEM) water electrolysis are part of the broad OECD definition of per- and polyfluoroalkyl substances (PFAS), a family of substances subject to increasing regulation. Potential PFAS emissions during commercial operation have been investigated in PEM fuel cells, but have not been reported for PEM electrolyzers. Based on previous measurements of fluoride release rates in water, potential emissions of fluorinated substances are likely to be detectable during the onset of stack operation. This observation is extended to evaluating potential PFAS emissions by collecting and analyzing recirculated water samples from a multi-megawatt PEM electrolyser plant in the first ~2 weeks of operation. No PFAS substances were detected using U.S. EPA Method 1633, consistent with the lack of observed degradation based on cell voltage and fluoride measurements. Methodologies for selecting and handling water samples were established. Minimizing gas crossover and maintaining water quality during electrolyzer operation can mitigate potential chemical degradation via hydroxyl radical formation. Implementing dual uses of the reverse osmosis deionization system to provide water and wastewater treatment can increase closed-loop operation and minimize potential PFAS emissions from wastewater.

Keywords

PEM water electrolysis / Environmental assessment / Fluoropolymers / Water testing / Use-phase emissions / Per- and polyfluoroalkyl substances

Acknowledgments

We thank Erika Fisher for advising on experimental design and analysis, and James Lalikos and Brad Parks for advising on discussion of results.

Author Contributions

Conceptualization, P.S.; Methodology, P.S. and B.T.; Formal Analysis, P.S.; Investigation, B.T.; Data Curation, B.T.; Writing—Original Draft Preparation, P.S.; Writing—Review and Editing, P.S. and B.T. All authors have read and agreed to the published version of the manuscript.

Ethics Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.

Funding

This research received no external funding.

Declaration of Competing Interest

Dr. Parikhit Sinha and Bibek Tripathi are employed by Electric Hydrogen Co., Devens. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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