Electrochemical treatment of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) in groundwater impacted by aqueous film forming foams (AFFFs)

•Electrochemical treatment of AFFF-impacted groundwater was demonstrated.•A divided electrochemical cell was used.•PFOS and PFOA removal was greater than that observed in previous studies using MMO anodes.•Defluorination was observed for both PFOS and PFOA.•Other long-chain perfluorinated compounds...

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Bibliographic Details
Published in:Journal of hazardous materials 2015-09, Vol.295, p.170-175
Main Authors: Schaefer, Charles E., Andaya, Christina, Urtiaga, Ana, McKenzie, Erica R., Higgins, Christopher P.
Format: Article
Language:English
Subjects:
Alkanesulfonic Acids - chemistry
Caprylates - chemistry
Electrochemical
Electrochemical Techniques
Fluorocarbons - chemistry
Groundwater - chemistry
Perfluorinated
PFOA
PFOS
Water Pollutants, Chemical - chemistry
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Summary:•Electrochemical treatment of AFFF-impacted groundwater was demonstrated.•A divided electrochemical cell was used.•PFOS and PFOA removal was greater than that observed in previous studies using MMO anodes.•Defluorination was observed for both PFOS and PFOA.•Other long-chain perfluorinated compounds also were treated. Laboratory experiments were performed to evaluate the use of electrochemical treatment for the decomposition of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), as well as other perfluoroalkyl acids (PFAAs), in aqueous film forming foam (AFFF)-impacted groundwater collected from a former firefighter training area and PFAA-spiked synthetic groundwater. Using a commercially-produced Ti/RuO2 anode in a divided electrochemical cell, PFOA and PFOS decomposition was evaluated as a function of current density (0–20mA/cm2). Decomposition of both PFOA and PFOS increased with increasing current density, although the decomposition of PFOS did not increase as the current density was increased above 2.5mA/cm2. At a current density of 10mA/cm2, the first-order rate constants, normalized for current density and treatment volume, for electrochemical treatment of both PFOA and PFOS were 46×10−5 and 70×10−5 [(min−1) (mA/cm2)−1 (L)], respectively. Defluorination was confirmed for both PFOA and PFOS, with 58% and 98% recovery as fluoride, respectively (based upon the mass of PFOA and PFOS degraded). Treatment of other PFAAs present in the groundwater also was observed, with shorter chain PFAAs generally being more recalcitrant. Results highlight the potential for electrochemical treatment of PFAAs, particularly PFOA and PFOS, in AFFF-impacted groundwater.
ISSN:0304-3894
1873-3336
DOI:10.1016/j.jhazmat.2015.04.024