Enhancing the Thermal Mineralization of Perfluorooctanesulfonate on Granular Activated Carbon Using Alkali and Alkaline-Earth Metal Additives DOI
Charbel Abou Khalil, L. V. Chernysheva, Anthony Miller

et al.

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

Low-temperature mineralization of perfluorocarboxylic acids DOI Open Access
Brittany Trang, Yuli Li, Xiao‐Song Xue

et al.

Science, Journal Year: 2022, Volume and Issue: 377(6608), P. 839 - 845

Published: Aug. 18, 2022

Per- and polyfluoroalkyl substances (PFAS) are persistent, bioaccumulative pollutants found in water resources at concentrations harmful to human health. Whereas current PFAS destruction strategies use nonselective mechanisms, we that perfluoroalkyl carboxylic acids (PFCAs) could be mineralized through a sodium hydroxide-mediated defluorination pathway. PFCA decarboxylation polar aprotic solvents produced reactive ion intermediates degraded fluoride ions (78 ~100%) within 24 hours. The carbon-containing products were inconsistent with oft-proposed one-carbon-chain shortening instead computationally identified pathways consistent many experiments. Degradation was also observed for branched ether might extended degrade other classes as methods activate their headgroups identified.

Language: Английский

Citations

219
Critical Review of Thermal Decomposition of Per- and Polyfluoroalkyl Substances: Mechanisms and Implications for Thermal Treatment Processes DOI
Junli Wang, Zunhui Lin,

Xuexiang He

et al.

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(9), P. 5355 - 5370

Published: April 21, 2022

Per- and polyfluoroalkyl substances (PFASs) are fluorinated organic chemicals that concerning due to their environmental persistence adverse human ecological effects. Remediation of PFAS contamination presence in consumer products have led the production solid liquid waste streams containing high concentrations PFASs, which require efficient cost-effective treatment solutions. PFASs challenging defluorinate by conventional advanced destructive processes, physical separation processes produce (e.g., membrane concentrate, spent activated carbon) requiring further post-treatment. Incineration other thermal widely available, but use managing PFAS-containing wastes remains poorly understood. Under specific operating conditions, is expected mineralize degradation mechanisms pathways unknown. In this review, we critically evaluate decomposition mechanisms, pathways, byproducts crucial design operation processes. We highlight analytical capabilities challenges identify research gaps limit current understanding safely applying destroy as a viable end-of-life process.

Language: Английский

Citations

136
Mechanisms and pathways of PFAS degradation by advanced oxidation and reduction processes: A critical review DOI
Mohamed Gar Alalm, Daria C. Boffito

Chemical Engineering Journal, Journal Year: 2022, Volume and Issue: 450, P. 138352 - 138352

Published: Aug. 2, 2022

Language: Английский

Citations

131
High-performance photocatalytic decomposition of PFOA by BiOX/TiO2 heterojunctions: Self-induced inner electric fields and band alignment DOI
Xiaoqing Liu, Xiaoguang Duan, Teng Bao

et al.

Journal of Hazardous Materials, Journal Year: 2022, Volume and Issue: 430, P. 128195 - 128195

Published: Feb. 12, 2022

Language: Английский

Citations

77
Degradation of Perfluorooctanoic Acid by Chlorine Radical Triggered Electrochemical Oxidation System DOI
Dongbao Song,

Biting Qiao,

Xin Wang

et al.

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(25), P. 9416 - 9425

Published: June 9, 2023

Electrochemical oxidation (EO) has been shown to have the unique ability degrade perfluorooctanoic acid (PFOA), although radical chemistry involved in this degradation is unclear, particularly presence of chloride ions (Cl–). In study, reaction kinetics, free quenching, electron spin resonance, and probes were used examine roles ·OH reactive chlorine species (RCS, including Cl·, Cl2•–, ClO·) EO PFOA. Using NaCl, PFOA rates 89.4%–94.9% defluorination 38.7%–44.1% achieved after 480 min with concentrations ranging from 2.4 240 μM. The occurred via synergistic effect Cl· rather than through direct anodic oxidation. products density functional theory (DFT) calculations revealed that triggered first step reaction, thus initial transfer was not rate-limiting degradation. change Gibbs energy caused by 65.57 kJ mol–1, which more two times lower ·OH. However, subsequent demonstrated for time promising development electrochemical technology remove perfluorinated alkyl substances environment.

Language: Английский

Citations

58
Electrostatic Field in Contact‐Electro‐Catalysis Driven C−F Bond Cleavage of Perfluoroalkyl Substances DOI
Yanfeng Wang, Jing Zhang, Wenkai Zhang

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(19)

Published: March 1, 2024

Abstract Perfluoroalkyl substances (PFASs) are persistent and toxic to human health. It is demanding for high‐efficient green technologies remove PFASs from water. In this study, a novel PFAS treatment technology was developed, utilizing polytetrafluoroethylene (PTFE) particles (1–5 μm) as the catalyst low frequency ultrasound (US, 40 kHz, 0.3 W/cm 2 ) activation. Remarkably, system can induce near‐complete defluorination different structured PFASs. The underlying mechanism relies on contact electrification between PTFE water, which induces cumulative electrons surface, creates high surface voltage (tens of volts). Such generate abundant reactive oxygen species (ROS, i.e., O ⋅ − , HO⋅, etc.) strong interfacial electrostatic field (IEF 10 9 ~10 V/m). Consequently, IEF significantly activates molecules reduces energy barrier nucleophilic reaction. Simultaneously, co‐existence (PTFE*( e )) HO⋅ enables synergetic reduction oxidation its intermediates, leading enhanced thorough defluorination. US/PTFE method shows compelling advantages consumption, zero chemical input, few harmful intermediates. offers new promising solution effectively treating PFAS‐contaminated drinking

Language: Английский

Citations

22
Estimated scale of costs to remove PFAS from the environment at current emission rates DOI
Alison L. Ling

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 918, P. 170647 - 170647

Published: Feb. 6, 2024

Language: Английский

Citations

16
The impact of anions on electrooxidation of perfluoroalkyl acids by porous Magnéli phase titanium suboxide anodes DOI Creative Commons

Yaye Wang,

Yifei Wang,

Shuping Dong

et al.

PLoS ONE, Journal Year: 2025, Volume and Issue: 20(1), P. e0317696 - e0317696

Published: Jan. 23, 2025

Previous studies have indicated the great performance of electrooxidation (EO) to mineralize per- and polyfluoroalkyl substances (PFASs) in water, but different anions presented wastewater may affect implementation EO treatment field applications. This study invetigated perfluorooctane sulfonate (PFOS) perfluorooctanoic acid (PFOA), two representative perfluoroalkyl acids (PFAAs), using porous Magnéli phase titanium suboxide anodes electrolyte solutions with present, including NO 3 - , SO 4 2- CO PO 3- . The experiment results indicate that enhanced PFAS degradation, while suppressed degradation reactions its concentration higher than 10 mM. exhibited less impact. Further electrochemical characterizations radical quenching experiments illustrate mechanisms how impact performance.

Language: Английский

Citations

2
An Investigation of Thermal Air Degradation and Pyrolysis of Per- and Polyfluoroalkyl Substances and Aqueous Film-Forming Foams in Soil DOI

Ali Alinezhad,

Pavankumar Challa Sasi,

Ping Zhang

et al.

ACS ES&T Engineering, Journal Year: 2022, Volume and Issue: 2(2), P. 198 - 209

Published: Jan. 11, 2022

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

Language: Английский

Citations

68
Destruction of perfluorooctanesulfonate (PFOS) in a batch supercritical water oxidation reactor DOI
Brian R. Pinkard, S. Divakara Shetty, Derek Stritzinger

et al.

Chemosphere, Journal Year: 2021, Volume and Issue: 279, P. 130834 - 130834

Published: May 18, 2021

Language: Английский

Citations

62