Real-time degradation dynamics of hydrated per- and polyfluoroalkyl substances (PFASs) in the presence of excess electrons

Yamijala, Sharma; Shinde, Ravindra; Wong, Bryan M.

doi:10.1039/c9cp06797c

Cited by 46 publications

(40 citation statements)

References 21 publications

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“…An understanding of the e aq – -mediated mechanism of degradation governing PFAS decomposition has yet to be fully elucidated. Recent reports on first-principles theoretical studies have attempted to advance our understanding of the elementary steps of the reaction pathway. ,, For example, in a report combining both experimental and theoretical results, Bentel et al demonstrated a strong dependence of the rate of degradation and defluorination of PFxS on the carbon chain length. However, the bond dissociation energies (BDE) calculated by DFT, in the same report by Bentel, could not explicitly explain this difference.…”

Section: Introductionmentioning

confidence: 99%

Nanosecond Transient Absorption of Hydrated Electrons and Reduction of Linear Perfluoroalkyl Acids and Sulfonates

Maza

Breslin

Owrutsky

et al. 2021

Environ. Sci. Technol. Lett.

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We report the rate constants (k q ) and activation energies (E a ) associated with the initial reduction of linear perfluoroalkyl carboxylates (PFxA, x = the number of carbons present in the surfactant) and perfluoroalkyl sulfonates (PFxS) by the hydrated electron (e aq − ) as measured using temperature-dependent transient absorption spectroscopy. The reduction of PFxA and PFxS by e aq − displays a negligible dependence on the number of carbons present in the surfactant and occurs with an apparent k q on the order of 10 8 to 10 9 M −1 s −1 with the k q corresponding to PFxA reduction being on average two times smaller than those for PFxS. There are no significant differences in the E a associated with PFxA or PFxS reduction; the magnitude of E a (∼11 kJ mol −1 ) is consistent with the reduction of PFxA and PFxS being a diffusion controlled process. These results are discussed within the framework of recent theoretical and experimental work on the degradation of PFxA and PFxS.

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Section: Introductionmentioning

confidence: 99%

Nanosecond Transient Absorption of Hydrated Electrons and Reduction of Linear Perfluoroalkyl Acids and Sulfonates

Maza

Breslin

Owrutsky

et al. 2021

Environ. Sci. Technol. Lett.

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“…A UV/sulfite system achieved a 98% decrease in PFOS concentration within 30 min (at a rate of 0.118 min –1 ), and a UV/iodide system achieved 52% decrease in PFOS concentration after 1.5 h (at a rate of 0.577 min –1 ). , Hydrated electrons are highly reactive and have extremely short lifespans under oxygen saturated conditions (about 10 –7 s) with a diffusion pathway of <2 nm. ,, Competing side-reactions that scavenge hydrated electrons include their reactions with protons, oxygen, and hydroxyl radicals . Thus, to increase the reaction between PFAS and hydrated electrons, different approaches can be used, including increasing the rate of production (sulfite or iodide addition), eliminating competing scavengers (oxygen, protons, hydroxyl radicals), and increasing the probability of reaction between the hydrated electron and PFAS.…”

Section: Introductionmentioning

confidence: 99%

Structural Dependence of Reductive Defluorination of Linear PFAS Compounds in a UV/Electrochemical System

Rao

Khor

et al. 2020

Environ. Sci. Technol.

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Per and polyfluoroalkyl substances (PFAS), legacy chemicals used in firefighting and the manufacturing of many industrial and consumer goods, are widely found in groundwater resources, along with other regulated compounds, such as chlorinated solvents. Due to their strong C− F bonds, these molecules are extremely recalcitrant, requiring advanced treatment methods for effective remediation, with hydrated electrons shown to be able to defluorinated these compounds. A combined photo/ electrochemical method has been demonstrated to dramatically increase defluorination rates, where PFAS molecules sorbed onto appropriately functionalized cathodes charged to low cell potentials (−0.58 V vs Ag/ AgCl) undergo a transient electron transfer event from the electrode, which "primes" the molecule by reducing the C−F bond strength and enables the bond's dissociation upon the absorption of a hydrated electron. In this work, we explore the impact of headgroup and chain length on the performance of this two-electron process and extend this technique to chlorinated solvents. We use isotopically labeled PFAS molecules to take advantage of the kinetic isotope effect and demonstrate that indeed PFAS defluorination is likely driven by a twoelectron process. We also present density functional theory calculations to illustrate that the externally applied potential resulted in an increased rate of electron transfer, which ultimately increased the measured defluorination rate.

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“…Non-stick cookwares are the metal cookware with a nonstock coating of PFASs. Per-and polyfluoroalkyl substances (PFASs) are the synthetic chemical compounds that are detrimental to the environment as well as human health (Yamijala et al, 2020). PFASs are one of the emerging concerns because its exposure may cause irregularities in growth, behaviour and learning of infants and mature children.…”

Section: Non-stickmentioning

confidence: 99%

Assessment of Indian cooking practices and cookwares on nutritional security: A review

Saxena

Saini

Samtiya

et al. 2021

JANS

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Food provides us nutrients and the energy required for growth, reproduction, and maintenance. Energy is required to perform all voluntary and involuntary activities like digestion, respiration, circulation, carrying out professional, household and recreational activities. Despite having rich food diversity, we are using only a few items as our staple food. With the adoption of eastern cooking practices and cookwares, risk of both pre-and post-transitional diseases like diabetes, cardiovascular diseases, malnutrition, obesity, etc. has increased significantly. Aluminium toxicity and nutrients breakdown has become a common problem in pressure cooking. To overcome this problem, it is important to shift from the modernized cooking methods to our traditional cooking practices, i.e., use of earthen cookwares, clay pots and some selected metal utensils, e.g., copper, iron, brass, etc. It has been shown that earthen, copper, iron, and soapstone cookwares do not leach toxic trace elements into the food and enhance the sensory qualities without decreasing the food nutrients. Adoption of traditional Indian cooking practices (such as fermentation, roasting, germination, etc.), cookwares (such as earthen, copper, iron, soapstone, etc.) and increasing the consumption of healthy diet grains like millets, etc. can easily combat the pre- and post-transition health problems in India, effectively. This review would provide a deep understanding to the people to decide the best cookware and cooking processes that will improve their health and provide ample nutritional value to them.

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Real-time degradation dynamics of hydrated per- and polyfluoroalkyl substances (PFASs) in the presence of excess electrons

Abstract: Per- and polyfluoroalkyl substances (PFASs) are harmful man-made chemicals that have contaminated several drinking water resources worldwide. Our work provides the first real-time assessment of PFAS degradation in the presence of excess electrons.

Cited by 46 publications

References 21 publications

Nanosecond Transient Absorption of Hydrated Electrons and Reduction of Linear Perfluoroalkyl Acids and Sulfonates

Nanosecond Transient Absorption of Hydrated Electrons and Reduction of Linear Perfluoroalkyl Acids and Sulfonates

Structural Dependence of Reductive Defluorination of Linear PFAS Compounds in a UV/Electrochemical System

Assessment of Indian cooking practices and cookwares on nutritional security: A review

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