Comment on “Biodegradation of perfluorooctanesulfonate (PFOS) as an emerging contaminant”

Avendaño, Sandra Mejia; Zhong, Guowei; Liu, Jinxia

doi:10.1016/j.chemosphere.2015.03.022

Cited by 14 publications

(4 citation statements)

References 7 publications

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“…The estimated global production of PFOS and a major precursor compound (perfluorooctane sulfonyl fluoride) was 122,500 t between 1970 and 2002 . Both PFOA and PFOS are resistant to degradation − and difficult to remove during conventional water and wastewater treatment. ,− The revised EU Water Framework Directive, which is subject to the final approval by the EU parliament, proposes a limit value of 100 ng/L for a total of 20 PFAS, including PFOA, PFOS, and their short-chain homologues . Certain short-chain PFAS are being included in the list of Persistent Mobile and Toxic substances …”

Section: Introductionmentioning

confidence: 99%

An Investigation of Thermal Air Degradation and Pyrolysis of Per- and Polyfluoroalkyl Substances and Aqueous Film-Forming Foams in Soil

et al. 2022

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In this study, we found that thermal decomposition of per- and polyfluoroalkyl substances (PFAS) in soil was rapid at moderate temperatures of 400–500 °C, regardless of whether the soil was contaminated by a single PFAS compound or a PFAS mixture in aqueous film-forming foams. Substantial degradation (>99%) of PFAS in soil, including perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), short-chain homologues, cationic and zwitterionic precursors, and PFOA and PFOS alternatives, occurred in 30 min at 500 °C in both a sealed reactor in air and a horizontal reactor under a continuous flow of N2. The effect of the initial PFAS level in soil (0.001–10 μmol/g) and soil texture was insignificant, provided a sufficiently high temperature was applied. Furthermore, this study showed, for the first time, that kaolinite dramatically decreased the apparent yield of F from PFAS heated at >300 °C, likely due to the chemisorption of F radicals on kaolinite. This phenomenon was not observed when kaolinite and an inorganic fluoride salt (NaF) were thermally treated. Lastly, various nonpolar thermal degradation products of PFOA and PFOS were reported for the first time. The profile of fluorinated volatiles, particularly perfluoroalkenes, was similar between these two chemicals. The results support a radical-mediated degradation pathway of PFAS.

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Section: Introductionmentioning

confidence: 99%

An Investigation of Thermal Air Degradation and Pyrolysis of Per- and Polyfluoroalkyl Substances and Aqueous Film-Forming Foams in Soil

et al. 2022

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“…Perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS), members of a group of compounds known as per- and polyfluoroalkyl substances (PFASs), have been detected in drinking water in many locations. − PFOA and PFOS are both resistant to degradation − and difficult to remove during conventional water and wastewater treatment. ,− The U.S. EPA recently released an updated drinking water advisory on PFOA and PFOS specifying a maximum combined level of 70 ng/L, making removal of PFOA/PFOS from drinking water − and remediation of PFAS-contaminated sites a priority issue. , …”

Section: Introductionmentioning

confidence: 99%

PFOA and PFOS Are Generated from Zwitterionic and Cationic Precursor Compounds During Water Disinfection with Chlorine or Ozone

Xiao

Hanson

Golovko

et al. 2018

Environ. Sci. Technol. Lett.

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Perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) are anionic organic pollutants, which are widespread in the environment. They have become a global concern due to their persistence in the environment as well as their toxicity and bioaccumulative properties. In this study, we demonstrate that PFOA, PFOS, or both are produced from a group of four zwitterionic/cationic polyfluoroalkyl amide (FA) and sulfonamide (FS) compounds during conventional drinking-water disinfection with chlorine or ozone. FA compounds were readily degraded by chlorine and converted primarily to PFOA, likely by a Hofmann-type rearrangement. FS compounds were much less reactive toward chlorine; the generation of PFOS from the FSs was not significant. All four FA and FS compounds were degraded rapidly during ozonation, generating PFOA, PFOS, and a number of infrequently reported products for which chemical structures were either confirmed or tentatively proposed using high-resolution mass spectrometry. FSs generated both PFOS and PFOA during ozonation with the yield of PFOA even higher than that from the FAs. The results of this study may provide important insight into the degradation mechanisms of FAs and FSs and shed light on their contribution to the secondary formation of PFOA and PFOS in natural and engineered systems.

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“…Aerobic biodegradation of saturated PFAA has been reported, but either without investigating degradation products, or with a PFCA as terminal degradation product (Chetverikov et al, 2017;Kwon et al, 2014;Yi et al, 2016). A comment on the publication by Kwon et al identified these issues and questioned the conclusion that PFOS was biodegraded (Mejia Avendaño et al, 2015).…”

Section: Biological Degradationmentioning

confidence: 99%

Innovative treatment technologies for PFAS-contaminated water - Utilizing foam partitioning and exploring electrochemical oxidation

Smith

2023

Acta Universitatis Agriculturae Sueciae

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The presence of per- and polyfluoroalkyl substances (PFAS) in the aquatic environment has become a global cause for concern. PFAS are persistent anthropogenic chemicals, and certain PFAS are known to be mobile, bioaccumulative and toxic. PFAS are often found in landfill leachate, effluents from industrial and municipal wastewater treatment plants, and groundwater contaminated with aqueous film-forming foam (AFFF). Conventional wastewater treatment technologies are typically inefficient towards the removal of PFAS. Therefore, this thesis aimed to explore the effectiveness of foam fractionation (FF) and electrochemical oxidation (EO) for PFAS removal and degradation. In FF, PFAS adsorb to rising air bubbles and are separated from the water as a concentrated foam. In this thesis, a continuous pilot-scale FF reactor was optimized for PFAS removal from landfill leachate, reaching ΣPFAS removal efficiencies of 60%. Gaps in the mass balance were identified, so a follow-up study assessed if emissions to air could explain this loss of PFAS. Here, FF could remove up to 84% of ΣPFAS from AFFF-contaminated industrial water. While the measured PFAS emissions to air were high, they did not contribute significantly to the mass balance. EO was tested as a destructive technology for the treatment of fractionated foam produced from groundwater and landfill leachate. Treatment effectiveness was assessed with thorough analysis strategies, including target analysis, PFAS sum parameters and effect-based methods, and a coupled numerical model was developed to describe the PFAS degradation kinetics. While the total degradation was higher with EO only, the energy efficiency of the FF+EO system was higher. Finally, the potential of integrating foam fractionation with existing treatment processes was investigated. Foam was sampled from ten different full-scale water treatment plants, and it was found that the ΣPFAS enrichment relative to the influent reached up to a factor of 105. However, no PFAS removal from influent to effluent was found, possibly because the foam was not actually removed in any of the processes. Altogether, this thesis contributes to an increased understanding of treatment options for PFAS contaminated water, with a particular focus on FF and EO.

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Comment on “Biodegradation of perfluorooctanesulfonate (PFOS) as an emerging contaminant”

Cited by 14 publications

References 7 publications

An Investigation of Thermal Air Degradation and Pyrolysis of Per- and Polyfluoroalkyl Substances and Aqueous Film-Forming Foams in Soil

An Investigation of Thermal Air Degradation and Pyrolysis of Per- and Polyfluoroalkyl Substances and Aqueous Film-Forming Foams in Soil

PFOA and PFOS Are Generated from Zwitterionic and Cationic Precursor Compounds During Water Disinfection with Chlorine or Ozone

Innovative treatment technologies for PFAS-contaminated water - Utilizing foam partitioning and exploring electrochemical oxidation

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