PFAS Destruction and Near-Complete Defluorination of Undiluted Aqueous Film-Forming Foams at Ambient Conditions by Piezoelectric Ball Milling

Environmental Science & Technology, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 16, 2025

The nonthermal destruction of aqueous film-forming foam (AFFF) stockpiles, one the major culprits responsible for water and soil contamination by per- polyfluoroalkyl substances (PFAS), is extremely challenging because coexistence mixed recalcitrant PFAS complicated organic matrices at high concentrations. To date, complete defluorination undiluted AFFF ambient conditions has not been demonstrated. This study reports a novel piezoelectric ball milling approach treating with total fluorine concentration 9080 mg/L carbon 234 g/L. Near-complete (>95% conversion organofluorine to fluoride) was achieved comilling boron nitride. By carefully examining experimental data, we identified liquid film thickness (Z) collision interface as descriptor treatment performance. We further validated that effective proceeded when Z less than criteria value 2.3 μm. In light this new understanding, addition SiO2 dispersant pre-evaporation solvents reduce have strategies promote capacity.

Language: Английский

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A Comprehensive Review of Novel Adsorbents for Per- and Polyfluoroalkyl Substances in Water

ACS ES&T Water, Journal Year: 2024, Volume and Issue: 4(4), P. 1191 - 1205

Published: March 8, 2024

Recent literature has seen a significant surge in studies focusing on new adsorbent materials for per- and polyfluoroalkyl substances (PFASg), class of contaminants found natural waters worldwide that pose considerable threat to human environmental health. Despite growing interest, the fundamental mechanisms PFAS adsorption these are not fully understood, thus hindering progress developing effective solutions removal. This Review aims bridge knowledge gap by offering critical appraisal recent innovations specifically designed treating PFAS. Strategies aimed at enhancing nanopore capacity or introducing anion-exchange capabilities have shown promise. Innovative such as carbon nanotubes, graphene, graphene oxide evaluated. Modified clay-based silica-based adsorbents demonstrated efficacy removing PFAS, driven hydrophobic effect, Coulombic interactions, electrostatic interactions. Polymers, ranging from types synthetic variants, promise removal across wide pH range. We discuss including F–F ion-pair adsorption, ion exchange chemically thermally modified provide general guideline design adsorbents. offers holistic view advances related materials.

Language: Английский

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Near-complete destruction of PFAS in aqueous film-forming foam by integrated photo-electrochemical processes

Nature Water, Journal Year: 2024, Volume and Issue: 2(5), P. 443 - 452

Published: May 1, 2024

Language: Английский

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Characterizing Volatile Emissions and Combustion Byproducts from Aqueous Film-Forming Foams Using Online Chemical Ionization Mass Spectrometry

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(8), P. 3942 - 3952

Published: Feb. 13, 2024

Aqueous film-forming foams (AFFFs) are used in firefighting applications and often contain per- polyfluoroalkyl substances (PFAS), which can detrimentally impact environmental biological health. Incineration is a potential disposal method for AFFFs, may produce secondary PFAS other air pollutants. We online chemical ionization mass spectrometry (CIMS) to measure volatile emissions from incinerating AFFF concentrate solutions. quantified perfluorinated carboxylic acids (PFCAs) during the incineration of legacy contemporary AFFFs. These included trifluoroacetic acid, reached mg m–3 quantities incinerator exhaust. PFCAs likely arose as products incomplete combustion fluorosurfactants with lower peak furnace temperatures yielding higher PFCA concentrations. also detected short-chain PFAS, novel emissions. The headspace above solutions contained larger (C ≥ 8), less oxidized by CIMS. identified neutral resembling fluorotelomer surfactants (e.g., sulfonamide alkylbetaines thioether amido sulfonates) alcohols headspaces. Directly comparing distinct spaces byproducts measured CIMS provides insight toward chemistry thermal treatment

Language: Английский

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Enhancing the Thermal Mineralization of Perfluorooctanesulfonate on Granular Activated Carbon Using Alkali and Alkaline-Earth Metal Additives

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(25), P. 11162 - 11174

Published: June 10, 2024

Thermal treatment has emerged as a promising approach for either the end-of-life or regeneration of granular activated carbon (GAC) contaminated with per- and polyfluoroalkyl substances (PFAS). However, its effectiveness been limited by requirement high temperatures, generation products incomplete destruction, necessity to scrub HF in flue gas. This study investigates use common alkali alkaline-earth metal additives enhance mineralization perfluorooctanesulfonate (PFOS) adsorbed onto GAC. When treated at 800 °C without an additive, only 49% PFOS was mineralized HF. All tested demonstrated improved mineralization, Ca(OH)2 had best performance, achieving efficiency 98% air N2. Its ability increase reaction rate shift byproduct selectivity suggests that role may be catalytic. Moreover, reduced gas instead reacting additive form inorganic fluorine (e.g., CaF2) starting waste material. A hypothesized mechanism is proposed involves electron transfer from O2– defect sites CaO intermediates formed during thermal decomposition PFOS. These findings advocate GAC disposal reuse, potential reduce operating costs mitigate environmental impact associated incinerating PFAS-laden wastes.

Language: Английский

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Headgroup Dependence and Kinetic Bottlenecks of Gas-Phase Thermal PFAS Destruction

ACS ES&T Engineering, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 2, 2025

Recent studies of thermal PFAS destruction have reported seemingly incoherent temperatures and products, often because decomposition pathways are highly dependent on the respective experimental system. Here, we applied accurate DLPNO–CCSD(T) coupled cluster calculations to isolate identify major processes during in gas phase, with relevance incineration, oxidation, other treatment technologies which their volatile products desorb into phase. All investigated perfluoroalkyl acids decompose via unimolecular headgroup loss, either through HF elimination or homolytic bond cleavage as a function type. In contrast, all fluorotelomers undergo initial hydrogen abstraction from characteristic C2H4 moiety by hydroxyl radicals under representative incineration conditions, followed radical decomposition. Subsequent formation perfluoroalkanes, including CF4, can then be prevented supplying sufficient donors such hydrocarbon fuel water well scavenging released fluorine. This leads generation stable 1H-perfluoroalkanes. While parent proceeds at gas-phase ≤700 °C, carbon–carbon 1H-perfluoroalkanes requires up ∼950 °C 2 s residence time, making this step kinetic bottleneck way complete mineralization.

Language: Английский

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Filling the Gaps in PFAS Detection: Integrating GC-MS Non-Targeted Analysis for Comprehensive Environmental Monitoring and Exposure Assessment

Environmental Science & Technology Letters, Journal Year: 2025, Volume and Issue: 12(2), P. 104 - 112

Published: Jan. 23, 2025

Per- and polyfluoroalkyl substances (PFAS) have garnered increasing attention in recent years, non-targeted analysis (NTA) has become essential for elucidating novel PFAS structures. NTA research been dominated by liquid chromatography–mass spectrometry (LC-MS) with gas (GC-MS) used less often as evidenced bibliometrics. However, the performance of GC-MS studies (GC-NTA) rivals that LC-ESI-MS, is shown to cover a complementary chemical space. An LC-ESI-MS amenability model applied list approximately 12,000 revealed than 10% known chemistry predicted be amenable typical LC-MS analysis. Therefore, there strong potential applying methods more fully assess environmental contamination landscape, uniquely shedding light on both PFAS, especially within space realm volatile semivolatile PFAS. Waste streams from fluorochemical manufacturing facilities heavily studied using targeted GC-MS; however, GC-NTA needed discover are not emitted facilities. Studies incineration PFAS-containing materials, such aqueous film forming foam, focused destruction parent compounds, little about transformation products formed during processes. holds elucidate when incinerated. Wastewater treatment plants landfills sources environment, yet understand air emissions these sources. Consumer lead indoor exposures via dust, but this area either or GC-MS. Despite challenges advancing GC-NTA, we call researchers, grantors, managers, other stakeholders recognize necessity so may face together.

Language: Английский

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A review on the occurrence of per- and polyfluoroalkyl substances in the aquatic environment and treatment trends for their removal

Journal of environmental chemical engineering, Journal Year: 2024, Volume and Issue: 12(5), P. 113325 - 113325

Published: June 12, 2024

Language: Английский

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Thermal Transformations of Perfluorooctanoic Acid (PFOA): Mechanisms, Volatile Organofluorine Emissions, and Implications to Thermal Regeneration of Granular Activated Carbon

Journal of Hazardous Materials, Journal Year: 2024, Volume and Issue: 479, P. 135737 - 135737

Published: Sept. 3, 2024

Language: Английский

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Thermochemistry of Species in Gas-Phase Thermal Oxidation of C₂ to C₈ Perfluorinated Carboxylic Acids

The Journal of Physical Chemistry A, Journal Year: 2024, Volume and Issue: 128(7), P. 1313 - 1326

Published: Feb. 9, 2024

New thermochemical properties,

Language: Английский

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