Hydrothermal Destruction and Defluorination of Trifluoroacetic Acid (TFA)

Environmental Science & Technology, Год журнала: 2024, Номер 58(18), С. 8076 - 8085

Опубликована: Апрель 25, 2024

Per- and polyfluoroalkyl substances (PFAS) have received increased attention due to their environmental prevalence threat public health. Trifluoroacetic acid (TFA) is an ultrashort-chain PFAS the simplest perfluorocarboxylic (PFCA). While US EPA does not currently regulate TFA, its chemical similarity other PFCAs simple molecular structure make it a suitable model compound for studying transformation of PFAS. We show that hydrothermal processing in compressed liquid water transforms TFA at relatively mild conditions (T = 150–250 °C, P < 30 MPa), initially yielding gaseous products, such as CHF3 CO2, naturally aspirate from solution. Alkali amendment (e.g., NaOH) promotes mineralization CHF3, dissolved fluoride, formate, carbonate species final products. Fluorine carbon balances are closed using Raman spectroscopy fluoride ion selective electrode measurements experiments performed alkaline conditions, where gas yields negligible. Qualitative FTIR analysis allows establishing pathways; however, F-balance could be quantitatively without NaOH amendment. The kinetics under measured, showing little no dependency on concentration, indicating thermal decarboxylation rate-limiting step. A proposed mechanism motivates additional work generalize reaction pathways PFCAs.

Язык: Английский

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Comprehensive Review of Global Perspectives on Per- and Polyfluoroalkyl Compounds: Occurrence, Fate, and Remediation in Groundwater Systems

Water, Год журнала: 2024, Номер 16(11), С. 1583 - 1583

Опубликована: Май 31, 2024

Groundwater contamination with per- and polyfluoroalkyl compounds (PFASs) has become a growing worldwide environmental issue. The current review comprehensively evaluates the global perspective of PFAS pollution in groundwater. Data from 224 recent research articles covering various land use source types were reviewed, including industrial facilities, landfills, biosolids applications, firefighting training sites. bibliographic analysis shows an exponential increase publications on groundwater last five years, more than 50% coming USA, followed by Australia, Canada, China, Sweden. provides insight into analytical techniques, absorbing materials, treatment strategies, field tests, enhanced natural attenuation. Nevertheless, identified significant gaps areas precursor characterization, subsurface behavior, model validation data, long-term sustainable solutions. Moreover, cross-disciplinary approach is required to reduce regulate PFASs’ risks humans ecological system. This presents case study PFASs Saudi Arabian groundwater, revealing elevated levels PFOA PFOS highlighting need for region-specific studies remediation strategies. results will guide efforts protect drinking water supplies life-threatening contaminants.

Язык: Английский

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PFAS in Landfill Leachate: Practical Considerations for Treatment and Characterization

Journal of Hazardous Materials, Год журнала: 2024, Номер unknown, С. 136685 - 136685

Опубликована: Ноя. 1, 2024

Язык: Английский

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PFAS removal through foam harvesting during wastewater aeration

Journal of Hazardous Materials, Год журнала: 2025, Номер unknown, С. 137936 - 137936

Опубликована: Март 1, 2025

Aeration in wastewater treatment plants (WWTPs) is used for removal of organic matter and nutrients. Here we show that aeration can also lead to per- polyfluoroalkyl substances (PFAS), by foam fractionation. Rising air bubbles facilitate air-liquid interfacial adsorption PFAS spontaneous foaming occurrence. This suggests some modifications conventional processes enable may be sufficient achieve at WWTPs. However, high suspended solids concentrations the mixed liquor suspension within aerated bioreactors complicate fractionation, as both biomass retain PFAS. study explored feasibility fractionation enrichment using actual suspensions with typical total WWTP-relevant concentrations. The mechanisms involved aqueous solid phases were suggested, a mass balance analysis was performed distribution between two phases. Overall, from phase ranged 70 % 100 perfluorinated carbon numbers ≥ 6, while < 6 showed low 20 %. 60 %, depending on species. represents an ongoing effort advance potential implementation

Язык: Английский

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PFAS removal via adsorption: A synergistic review on advances of experimental and computational approaches

Chemosphere, Год журнала: 2025, Номер 377, С. 144323 - 144323

Опубликована: Март 29, 2025

Язык: Английский

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Degradation and Defluorination of Ultra Short-, Short-, and Long-Chain PFASs in High Total Dissolved Solids Solutions by Hydrothermal Alkaline Treatment─Closing the Fluorine Mass Balance

ACS ES&T Engineering, Год журнала: 2024, Номер unknown

Опубликована: Сен. 25, 2024

Язык: Английский

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Electrochemical Destruction of PFAS at Low Oxidation Potential Enabled by CeO2 Electrodes Utilizing Adsorption and Activation Strategies

Journal of Hazardous Materials, Год журнала: 2024, Номер 486, С. 137043 - 137043

Опубликована: Дек. 30, 2024

Язык: Английский

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How to take ‘forever’ out of forever chemicals

Nature, Год журнала: 2023, Номер unknown

Опубликована: Дек. 14, 2023

Язык: Английский

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Available and emerging liquid treatment technologies for PFASs

Remediation Journal, Год журнала: 2024, Номер 34(3)

Опубликована: Апрель 1, 2024

Abstract Per‐ and polyfluoroalkyl substances (PFASs) are present at a wide range of private sector facilities United States (US) government installations, including those operated by the Department Defense, Energy, National Aeronauts Space Administration, other entities, as well additional sites worldwide. Impacts have been identified in environmental media drinking water, groundwater, surface leachate, wastewater, soil, sediment, soil gas. Treatment technologies to remove or destroy PFASs cost effectively proven be elusive industry. However, recent developments bringing that goal close reality for some media. This article has prepared address only liquid treatment technologies. Soil presently lower priority may addressed future articles. The challenge identifying evaluating available emerging was put PFAS Experts Symposium Houston, Texas, on June 7–8, 2023, which attended professionals subject matter experts with broad backgrounds. discussions covered variety technical approaches led preparation this manuscript. strives concisely summarize modern potentially applicable managing PFAS‐impacted sites. Currently, ex situ sorbent using granular activated carbon (GAC) ion exchange (IX) resin commercially most widely used. Other summarized current applications presented allow reader evaluate each technology their particular use. is not intended provide guidance site‐specific design systems, but instead serve an update earlier articles from group others addressing related topics.

Язык: Английский

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Regeneration of PFAS-laden Granular Activated Carbon in Modified Supercritical CO2 Extraction

Опубликована: Июнь 3, 2024

Granular activated carbon (GAC) is used widely to treat PFAS-contaminated streams, resulting in large quantities of spent GAC that are landfilled or regenerated for future use. Herein, we report the development and application supercritical CO2 (scCO2) extraction modified with organic solvent acid modifier. The method yields > 97% desorption efficiency PFOA after ~60 minutes treatment a continuous flow reactor. mild conditions at ~100 °C do not trigger formation volatile fluorine alteration sorbent properties. Another benefit using scCO2 high miscibility co-solvent/scCO2, which eliminates diffusion transport limitations, enabling rapid PFAS into single-phase (gas-like) medium. introduction an co-solvent absence water as limit hydrophobic interactions between adsorbate. At same time, addition modifiers reduces electrostatic sorbents. Supercritical fluid (SFE) may prove effective other types sorbents, including various ion-exchange resins. SFE process can be economically regeneration scheme, leading reuse sorbents adsorption cycles achieving concentration effluent end-of-life technologies.

Язык: Английский

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