POTENTIAL PFAS DESTRUCTION TECHNOLOGY:
ELECTROCHEMICAL OXIDATION

f'ERM Research BRIEF

www.epa.gov/research

INNOVATIVE RESEARCH FOR A SUSTAINABLE FUTURE

In Spring 2020, the EPA established the PFAS Innovative
Treatment Team (PITT). The PITT was a multi-disciplinary
research team that worked full-time for 6-months on
applying their scientific efforts and expertise to a single
problem: disposal and/or destruction of PFAS-
contaminated media and waste. While the PITT formally
concluded in Fall 2020, the research efforts initiated under
the PITT continue.

As part of the PITT's efforts, EPA researchers considered
whether existing destruction technologies could be applied
to PFAS-contaminated media and waste. This series of
Research Briefs provides an overview of four technologies
that were identified by the PITT as promising technologies
for destroying PFAS and the research underway by the
EPA's Office of Research and Development to further
explore these technologies. Because research is sti 1
needed to evaluate these technologies for PFAS
destruction, this Research Brief should not be considered
an endorsement or recommendation to use this
technology to destroy PFAS.

Background

Various industries have produced and used per- and
polyfluoroalkyl substances (PFAS) since the mid-20th
century. PFAS are found in consumer and industrial
products, including non-stick coatings, waterproofing
materials, and manufacturing additives. PFAS are stable
and resistant to natural destruction in the environment,
leading to their pervasive presence in groundwater, surface
waters, drinking water and other environmental media
(e.g., soil) in some localities. Certain PFAS are also
bioaccumulative, and the blood of most U.S. citizens
contains detectable levels of several PFAS (CDC, 2009). The
toxicity of PFAS is a subject of current study and enough is
known to motivate efforts to limit environmental release
and human exposure (EPA, 2020).

To protect human health and the environment, EPA
researchers are identifying technologies that can destroy
PFAS in liquid and solid waste streams including
concentrated and spent (used) fire-fighting foam, biosolids,
soils, and landfill leachate. These technologies should be
readily available, cost effective, and produce little to no





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Figure 1. Mechanisms of electrochemical oxidation.

hazardous residuals or byproducts. Electrochemical
oxidation (EC) has been identified as a promising
technology that may be able to meet these requirements
with further development, testing, and demonstrations.

Electrochemical Oxidation: Technology Overview

EC is a water treatment technology that uses electrical
currents passed through a solution to oxidize pollutants.
EC treatment of persistent organic pollutants, such as
PFAS, has been demonstrated at the bench and pilot
scale (Nzeribe et al,, 2019). Advantages of EC include:
low energy costs, operation at ambient conditions, ability
to be in a mobile unit, and no requirement for chemical
oxidants as additives (Garcia-Segura et al. 2018).
Limitations of this technology include the potential
generation of toxic byproducts, incomplete destruction
of some PFAS, efficiency losses due to mineral build up
on the anode, high cost of electrodes, and potential
volatilization of contaminants (Schaefer et al., 2019;
Nzeribe et al., 2019). Despite these potential limitations,
EC may be a promising technology for PFAS destruction
in certain instances because of its demonstrated ability
to destroy PFAS with lower energy demands than
thermal incineration.

As shown in Figure 1, both direct and indirect oxidation
mechanisms are possible, although the mechanisms that

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January 2021

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occur vary with the specific PFAS. Direct oxidation can
result by electron transfer from the PFAS compound to the
anode, while indirect mechanisms involve
electrochemically-created, powerful oxidants known as
radicals (such as the hydroxyl radical, OH", shown in Figure
1). Through a series of reactions, intermediate products are
separated from the parent compound and subsequently
defluorinated (Schaefer et al., 2019; Zhuo et al., 2012;
Nzeribe et al., 2019). The speed of EC treatment of PFAS is
dependent on several variables, including: electrode
composition and surface area, initial PFAS concentration,
desired level of treatment, voltage, and co-contaminants.
Treatment duration using two-dimensional electrodes is
expected to be on the order of hours; however, recent
advances, including development of a reactive EC
membrane system, may be able to reduce the treatment
time to seconds (Le et al., 2019). It is important to note
that most of the testing completed to date has used
laboratory control waste streams (i.e. clean waters spiked
with PFAS rather than real-world waste streams). Real-
world waste streams may require longer treatment times
and may see reduced performance and electrode lifetime.

While commercially-available boron-doped diamond (BDD)
electrodes are the most common and most widely
evaluated in the literature, they are costly (~$7,125/m2)
and difficult to produce (Chaplin, 2019). Other mixed metal
oxide electrodes, such as Ti407, are a fraction of the cost of
BDD and have demonstrated effectiveness for PFAS
destruction but have yet to be commercialized (Le et al.,
2019). Very limited work has been done to evaluate long-
term EC treatment, and the expected lifespan of these
electrodes is unknown (Schaefer et al., 2019). Operational
costs are primarily driven by energy consumption (Le et al.,
2019). While significant work is being done to overcome
these limitations, the initial cost, availability, and lifecycle
costs of electrodes remain significant barriers to full-scale
use of EC for PFAS destruction.

EC is known to produce perchlorate through oxidation of
chloride in solution. Perchlorate generation and treatment
should be considered when evaluating overall cost and
feasibility of EC for PFAS-laden streams. Several authors
have reported destruction of PFAS via EC treatment when
evaluating individual compounds, such as PFOS and PFOA,
but the fate of the fluorine within the process has not yet
been fully assessed in a mass balance, making potential
fluorinated byproducts a possibility (Nzeribe et al., 2019).
This is especially concerning because some hazardous
intermediate degradation compounds, such as
trifluoroacetic acid, are volatile (Schaefer et al., 2015;
2017; Nzeribe et al., 2019).

Potential for PFAS Destruction

Researchers report reductions of the parent compounds,
but complete PFAS destruction has yet to be confirmed
as the potential for formation of products of incomplete
destruction has yet to be fully evaluated. Removal here
means the effluent contains less of the parent
compounds than the influent. Liang et al. (2018) reported
total removal of 77.2 and 96.5% of PFOA and PFOS,
respectively, from ion-exchange resin regenerate (still
bottom) with a Ti407 electrode. Xu et al. (2017) reported
97% removal efficiency of PFOA with a Zr-Pb02 film
electrode. And Gomez-Ruiz et al. (2017) reported 99.7%
removal of 8 PFAS with a BDD electrode. The time
required for parent compound removal varied greatly
among these studies and the technologies are still under
development but the initial results are promising.

Research Gaps

Development of EC into a readily available PFAS
destruction technology can be aided by: (i) reduction in
cost of electrodes; (ii) coupling the process with a
method to treat perchlorate and other byproducts; (iii)
evaluation of long-term operation of EC to determine
lifecycle electrode costs and evaluate process limitations
from impacts of mineral build up; (iv) analysis of
potential byproducts to understand that PFAS
compounds are being completely degraded; (v) field
demonstration of effective scale-up and optimization of
process parameters. Currently, EC is assessed to have an
intermediate technology readiness level, and further
work is needed in multiple areas to maximize technology
readiness (Lacasa et al. 2019).

Next Steps

EC is one of the technologies being evaluated by EPA
researchers for PFAS destruction. EPA researchers are
conducting pilot-scale testing to evaluate PFAS
destruction under a variety of conditions. EPA expects to
publish the results of this work in 2021.

References

Centers for Disease Control and Prevention (CDC). 2009.
Fourth National Report on Human Exposure to
Environmental Chemicals.

https://www.cdc.gov/exposurereport/pdf/fourthrep
ort.pdf. Accessed Jan. 15, 2021.

Chaplin, B. P. 2019. The prospect of electrochemical
technologies advancing worldwide water treatment.
Acc. Chem. Res. 52(3):596-604.

Garcia-Segura, S.; Ocon, J. D.; Chong, M. N. 2018.
Electrochemical oxidation remediation of real
wastewater effluents — A review. Process Saf.
Environ. 113:48-67.

B

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Gomez-Ruiz, B.; Gomez-Lavfn, S.; Diban, N.; Boiteux, V.,
Colin, A.; Dauchy, X.; Urtiaga, A. 2017. Efficient
electrochemical degradation of poly-and perfluoroalkyl
substances (PFASs) from the effluents of an industrial
wastewater treatment plant. Chem. Eng. J. 322:196-
204.

Lacasa, E.; Cotillas, S.; Saez, C.; Lobato, J.; Canizares, P.;
Rodrigo, M. A. 2019. Environmental applications of
electrochemical technology: What is needed to enable
full-scale applications? Curr. Opin. Electrochem.
16:149-156.

Le, T. X. H.; Haflich, H.; Shah, A. D.; Chaplin, B. P. 2019.
Energy-efficient electrochemical oxidation of
perfluoroalkyl substances using a Ti4C>7 reactive
electrochemical membrane anode. Environ. Sci. Tech.
Lett. 6(8):504-510.

Liang, S., Pierce Jr., R. D.; Lin, H.; Chiang, S. Y.; Huang, Q. J.

2018.	Electrochemical oxidation of PFOA and PFOS in
concentrated waste streams. Remediation. 28(2):127-
134.

Nzeribe, B. N.; Crimi, M.; Thagard, S. M.; Holsen, T. M.

2019.	Physico-chemical processes for the treatment of
per- and polyfluoroalkyl substances (PFAS): A review.
Crit. Rev. Environ. Sci. Tech. 49(10):866-915.

Schaefer, C. E.; Andaya, C.; Burant, A.; Condee, C. W.;
Urtiaga, A.; Strathmann, T. J.; Higgins, C. P. 2017.
Electrochemical treatment of perfluorooctanoic acid
and perfluorooctane sulfonate: Insights into
mechanisms and application to groundwater
treatment." Chem. Eng. J. 317: 424-432.

Schaefer C. E.; Andaya, C.; Maizel, A.; Higgins, C. P. 2019.
Assessing continued electrochemical treatment of
groundwater impacted by aqueous film-forming
foams. J. Environ. Eng. 145(12): 06019007.

Schaefer, C. E.; Andaya, C.; Urtiaga, A.; McKenzie, E. R.;
Higgins, C. P. 2015. Electrochemical treatment of
perfluorooctanoic acid (PFOA) and perfluorooctane
sulfonic acid (PFOS) in groundwater impacted by
aqueous film forming foams (AFFFs). J. Hazard. Mater.
295:170-75.

US EPA (EPA). 2020. Basic information on PFAS.

https://www.epa.Eov/pfas/basic-information-pfas.
Accessed Sept. 15, 2020.

Xu, Z.; Yu, Y.; Liu, H.; Niu, J. 2017. Highly efficient and stable
Zr-doped nanocrystalline Pb02 electrode for
mineralization of perfluorooctanoic acid in a sequential
treatment system. Sci. Total Environ. 579:1600-1607.

Zhuo, Q.; Deng, S.; Yang, B.; Huang, J.; Wang, B.; Zhang, T.;
Yu, G. 2012. Degradation of perfluorinated compounds

on a boron-doped diamond electrode. Electrochim.
Acta 77:17-22.

Contacts

•	Max Krause - krause.max@epa.gov

•	Matthew Magnuson - maEnuson.matthew(a)epa.Eov

•	Brian Crone - crone.brian@epa.gov

Note: This Research Brief is a summary of research
conducted by the EPA's Office of Research and
Development and does not necessarily reflect EPA
policy.

U.S. Environmental Protection Agency

January 2021

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