Effect of chemical structure on the sonochemical degradation of perfluoroalkyl and polyfluoroalkyl substances (PFASs)

Fernandez, Nerea Abad; Rodríguez-Freire, Lucía; Keswani, Manish; Sierra-Álvarez, Reyes

doi:10.1039/c6ew00150e

Cited by 61 publications

(40 citation statements)

References 48 publications

(82 reference statements)

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“…Sonolytic degradation of PFOA ( Figure 1a (pseudo first order), are lower than previously reported values in the literature [10][11][12]33]. This is due to lower ultrasound power density (77 W L -1 ) and power intensity (0.69 W cm -2 ) in this study compared to 250 W L -1 and 6.4 W cm -2 used by [11] for a similar initial concentration (20 μM) of PFOA and PFOS.…”

Section: Resultscontrasting

confidence: 63%

“…Campbell and Hoffman (2015) observed insignificant degradation of PFAS at an ultrasonic frequency of 20 kHz using probe sonication [9]. Many studies reported highfrequency ultrasound (> 202 kHz), which uses a vibrating flat plate transducer, as a promising technology to mineralize PFOA and PFOS [10][11][12]. However, the sonochemical process optimization would benefit from a deeper understanding of the dynamics of PFAS adsorption at the collapsible cavity-water interface.…”

Section: Introductionmentioning

confidence: 99%

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Kinetic model for sonolytic degradation of non-volatile surfactants: Perfluoroalkyl substances

Shende

Andaluri

Suri

2019

Ultrasonics Sonochemistry

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Sonolytic degradation kinetics of non-volatile surfactant perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were investigated over a range of concentration, considering active cavity as a catalyst. The Michaelis-Menten type kinetic model was developed to empirically estimate the concentration of active cavity sites during reactions. Sonolytic degradation of PFOA and PFOS, as well as the formation of its inorganic constituents, fluoride, and sulfate, follows saturation kinetics of pseudo-first order at lower concentration (<2.34 µM) and zero order at higher concentration (>23.60 µM). Nitrate and hydrogen peroxide formations were 0.53 ± 0.14 µM/min and 0.95 ± 0.11 µM/min, respectively. At a power density of 77 W/L and frequency of 575 kHz, the empirically estimated maximum number of active cavity sites that could lead to the sonolytic reaction were 89.25 and 8.8 mM for PFOA and PFOS, respectively. This study suggests that a lower number of active cavity sites with higher temperature needed to degrade PFOS might be the reason for lower degradation rate of PFOS compared to that of PFOA. Diffusion of non-volatile surfactants at the cavity-water interface is found to be the rate-limiting step for the mineralization of perfluoroalkyl substances.

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Section: Resultscontrasting

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Kinetic model for sonolytic degradation of non-volatile surfactants: Perfluoroalkyl substances

Shende

Andaluri

Suri

2019

Ultrasonics Sonochemistry

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“…Sonolysis appears to destroy a wide range of PFAS compounds (long chain and short chain), with consistent observations of pseudo-first order rate kinetics and faster kinetics for larger PFASs with more fluorination (perfluorinated > polyfluorinated; Fernandez et al, 2016;Rayne & Forest, 2009;Rodriguez-Freire et al, 2016;Rodriguez-Freire et al, 2015). One limitation of the available sonolysis data for PFASs is that the focus is on viability and, therefore, high concentrations of PFAS are used (>10,000 ng/L).…”

Section: Sonolysismentioning

confidence: 57%

“…When the microbubbles are collapsed during compression cycles, significant energy is released in the form of heat, and literature observations suggest achievable temperatures of up to 5,000 degrees Kelvin within the bubbles (Campbell, Vecitis, Mader, & Hoffmann, ). For scale‐up, there are many optimization factors that can be explored (sound field distribution, bubbling gas in‐line, pH changes, and changing the external temperature and pressure) as well as the generation of the hydroxyl radical, which may have varying degrees of success for different PFAS (Cheng, Vecitis, Park, Mader, & Hoffmann, ; Drees, ; Fernandez, Rodriguez‐Freire, Keswani, & Sierra‐Alvarez, ; Hao, Guo, Wang, Leng, & Li, ; Mason, ; Moriwaki et al., ; Rayne & Forest, ; Rodriguez‐Freire, Balachandran, Sierra‐Alvarez, & Keswani, ; Vecitis, Park, Cheng, Mader, & Hoffmann, ; Vecitis et al., ).…”

Section: Electrochemical Oxidationmentioning

confidence: 99%

“…Most non‐PFAAs sonolysis applications are operated between 20 kHz and 40 kHz because of input energy requirements. To treat a broad range of organic contaminants (including PFAAs), a frequency range of 500 kHz to 1,100 kHz seems appropriate based on demonstrations in the literature (Fernandez et al., ; Rodriguez‐Freire et al., ; Rodriguez‐Freire et al., ), but site‐specific, real‐time data observations are suggested to specify a design frequency. Available demonstrations in the literature explore PFAS treatment with sonolysis at frequencies greater than 200 kHz to maximize the surface area and resultant contact between PFAS molecules and microbubbles (Cheng et al., ; Drees, ; Hao et al., ; Mason, ; Moriwaki et al., ; Rayne & Forest, ; Rodriguez‐Freire et al., ; Vecitis et al., ; Vecitis et al., ).…”

Section: Electrochemical Oxidationmentioning

confidence: 99%

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A review of emerging technologies for remediation of PFASs

Ross

McDonough

Miles

et al. 2018

Remediation Journal

381

268

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The need for remediation of poly‐ and perfluoroalkyl substances (PFASs) is growing as a result of more regulatory attention to this new class of contaminants with diminishing water quality standards being promulgated, commonly in the parts per trillion range. PFASs comprise >3,000 individual compounds, but the focus of analyses and regulations has generally been PFASs termed perfluoroalkyl acids (PFAAs), which are all extremely persistent, can be highly mobile, and are increasingly being reported to bioaccumulate, with understanding of their toxicology evolving. However, there are thousands of polyfluorinated “PFAA precursors”, which can transform in the environment and in higher organisms to create PFAAs as persistent daughter products. Some PFASs can travel miles from their point of release, as they are mobile and persistent, potentially creating large plumes. The use of a conceptual site model (CSM) to define risks posed by specific PFASs to potential receptors is considered essential. Granular activated carbon (GAC) is commonly used as part of interim remedial measures to treat PFASs present in water. Many alternative treatment technologies are being adapted for PFASs or ingenious solutions developed. The diversity of PFASs commonly associated with use of multiple PFASs in commercial products is not commonly assessed. Remedial technologies, which are adsorptive or destructive, are considered for both soils and waters with challenges to their commercial application outlined. Biological approaches to treat PFASs report biotransformation which creates persistent PFAAs, no PFASs can biodegrade. Water treatment technologies applied ex situ could be used in a treatment train approach, for example, to concentrate PFASs and then destroy them on‐site. Dynamic groundwater recirculation can greatly enhance contaminant mass removal via groundwater pumping. This review of technologies for remediation of PFASs describes that: GAC may be effective for removal of long‐chain PFAAs, but does not perform well on short‐chain PFAAs and its use for removal of precursors is reported to be less effective; Anion‐exchange resins can remove a wider array of long‐ and short‐chain PFAAs, but struggle to treat the shortest chain PFAAs and removal of most PFAA precursors has not been evaluated; Ozofractionation has been applied for PFASs at full scale and shown to be effective for removal of total PFASs; Chemical oxidation has been demonstrated to be potentially applicable for some PFAAs, but when applied in situ there is concern over the formation of shorter chain PFAAs and ongoing rebound from sorbed precursors; Electrochemical oxidation is evolving as a destructive technology for many PFASs, but can create undesirable by‐products such as perchlorate and bromate; Sonolysis has been demonstrated as a potential destructive technology in the laboratory but there are significant challenges when considering scale up; Soils stabilization approaches are evolving and have been used at full scale but performance need to be assessed usin...

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Managing and treating per‐ and polyfluoroalkyl substances (PFAS) in membrane concentrates

et al. 2021

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Per-and polyfluoroalkyl substances (PFAS), which are present in many waters, have detrimental impacts on human health and the environment. Reverse osmosis (RO) and nanofiltration (NF) have shown excellent PFAS separation performance in water treatment; however, these membrane systems do not destroy PFAS but produce concentrated residual streams that need to be managed. Complete destruction of PFAS in RO and NF concentrate streams is ideal, but long-term sequestration strategies are also employed. Because no single technology is adequate for all situations, a range of processes are reviewed here that hold promise as components of treatment schemes for PFAS-laden membrane system concentrates. Attention is also given to relevant

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Effect of chemical structure on the sonochemical degradation of perfluoroalkyl and polyfluoroalkyl substances (PFASs)

Abstract: The study provides insights into the effect of carbon chain length, functional group substitutions and chemical structure on sonochemical degradation of perfluoroalkyl and polyfluoroalkyl substances.

Cited by 61 publications

References 48 publications

Kinetic model for sonolytic degradation of non-volatile surfactants: Perfluoroalkyl substances

Kinetic model for sonolytic degradation of non-volatile surfactants: Perfluoroalkyl substances

A review of emerging technologies for remediation of PFASs

Managing and treating per‐ and polyfluoroalkyl substances (PFAS) in membrane concentrates

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