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Per- and polyfluoroalkyl substances (PFAS) are highly stable ubiquitous contaminants that have been recently added to the list of regulated chemicals. While methods for PFAS detection exist, analysis is difficult, involving a tedious protocol and expensive instrumentation. Here, we demonstrate the first implementation of a phenoxazine dye as a sensing probe that facilitates rapid and inexpensive detection of representative PFAS, e.g., perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), at sensitivity levels covering the recently established Environmental Protection Agency (EPA) limits. The method comprises an electrode modified with a stable redox film of Meldola blue (MB) in its electropolymerized form ( ep MB), which provides amino sites for electrostatic interactions with PFAS. Long-chain PFAS bind specifically to the ep MB, inducing a hydrophobic-type cluster formation through ion-pair and F-F interactions. This binding generates concentration-dependent changes in the ep MB/ ep MB + oxidation, enabling rapid and sensitive quantification in a single step with high sensitivity, reaching a limit of detection of 0.4 ppt for PFOS and 1.65 ppt for PFOA. The sensor demonstrates good selectivity toward common interfering compounds like humic acid, sodium chloride and fluoride, metallic ions (Cu, Hg, As), as well as pesticides. In addition to PFOS and PFOA, the sensors can measure other perfluoroalkyl compounds, demonstrating potential as a tool for rapid quantification of a total PFAS index, with affinity for long-chain PFAS. This work highlights the integration of redox receptors into an electrochemical sensor to solve the grand challenge of PFAS analysis using a rapid and inexpensive procedure, with potential for field deployment.

By preparing Cu@CuO aerogel as a nanozyme which exhibits prominent peroxidase-like (POD) activity, an innovative homogeneous electrochemistry (HEC) coupled with the colorimetry dual-model sensing strategy is proposed to detect perfluorooctane sulfonate (PFOS) for the first time. Cu@CuO aerogel accelerates the oxidation process of colorless o-phenylenediamine to form yellow 2,3-diaminophenazinc (DAP), and meanwhile, DAP as an electroactive substance creates a reduction peak current upon the electrochemical measurements. Interestingly, in the presence of PFOS, the POD activity of Cu@CuO aerogel is inhibited since the specific coordination between PFOS and Cu(II) can cover the active sites, resulting in the color of the sensing system becoming light and the peak current of DAP decreasing. This innovative dual-mode detection method showed excellent electrochemical detection of PFOS in the concentration range 10.0 ~ 1125.0 nM with a limit of detection (LOD) as low as 3.3 nM and a LOD of 20.8 nM in the colorimetric detection in the range 62.3 ~ 875 nM. Furthermore, the sensor was successfully used for the analysis of real samples with an RSD value  ≤ 6.5%. The successful application of this two-mode sensing method for the determination of PFOS holds promise for the detection of other contaminants in the future., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Models to predict perfluorooctanesulfonic acid (PFOS) concentrations in livestock based on soil concentrations are essential to guide decisions surrounding food testing and farm management. A key parameter in modeling soil-to-livestock exposure pathways is the plant transfer factor (TF) from soil into forages. Uptake of PFOS and other individual per- and polyfluoroalkyl substances (PFASs) were examined in perennial mixed grasses and legumes on PFAS-contaminated farm fields. In a field plot study, PFOS TFs were similar within each plot over three consecutive years but varied 10-fold among the four plots with mean TFs ranging from 0.026 to 0.27. In a multifarm field survey study, mean PFOS TFs ranged from 0.039 to 0.37. Increasing concentrations of two PFOS precursors in soil were significantly associated with increasing PFOS TFs. These data represent a substantial increase in empirical observations of PFAS TFs for grass-based forages for use in modeling soil-to-livestock exposure scenarios.

Stored rainwater, the primary source of drinking water in the villages and towns of the Loess Plateau in northwest China, has been found to contain per- and polyfluoroalkyl substances (PFASs) and lacks necessary treatment measures. Coagulation is a common water treatment process, and enhancing its efficacy in removing PFASs can significantly improve treatment efficiency, reduce costs, and minimize the environmental and health risks associated with perfluorinated compounds. This study investigated the removal efficiency of perfluorobutanoic acid (PFBA), perfluorobutanesulfonic acid (PFBS), perfluorooctanoic acid (PFOA), and perfluorooctanesulfonic acid (PFOS) using inorganic salt coagulants alone and in combination with polydimethyldiallylammonium chloride (PDMDAAC). The results indicated that the removal efficiencies of the four PFASs by polyferric chloride (PFCl) and polyaluminum chloride (PACl) increased with alkalinity. PDMDAAC significantly enhanced the coagulation removal efficiency of the four PFASs. The removal efficiency of the four PFASs was highest when the raw water pH was near 7. Within the molecular weight range of 0-500,000 for PDMDAAC, the removal efficiency of the four PFASs increased with increasing molecular weight. Charge neutralization is the primary coagulation mechanism for the removal of anionic PFASs. Therefore, this study provides guidance for selecting coagulants to remove PFASs from stored rainwater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Microplastics (MPs) have become an emerging anthropogenic pollutant, and their ability to sorb contaminants potentially enhances the threats to the ecosystem. Only a few studies are available to understand the combined effects of microplastics and other pollutants. The present study investigated the sorption of perfluorooctane sulfonic acid (PFOS) onto polystyrene microplastics (PS-MPs) at varying concentrations, using molecular dynamics simulation (MDS) to preliminarily explore the adsorption behavior. The MDS results revealed negative interaction energies between PFOS and PS-MPs, underscoring PS-MPs' role as a potential adsorbent for PFOS in an aqueous solution. Thereafter, zebrafish embryos were employed to explore the toxic effects of combined exposure to PS-MPs and PFOS. Fluorescence and Scanning Electron Microscopy (SEM) suggested PS-MP accumulation individually and in combination with PFOS on the embryonic chorion membrane. As a result, the exposed group showed increased inner pore size of the chorionic membrane and accelerated heartbeat, indicating hypoxic conditions and hindered gaseous exchange. PS-MPs aggravated the toxicity of PFOS during larval development manifested by delayed hatching rate, increased mortality, and malformation rate. Additionally, increased ROS accumulation and altered antioxidant enzymatic status were observed in all the exposed groups suggesting perturbation of the redox state. Additionally, co-exposure of zebrafish larvae to PS-MPs and PFOS resulted in an abrupt behavioral response, which decreased AChE activity and altered neurotransmitter levels. Taken together, our results emphasize that PS-MPs can act as a potential vector for PFOS, exerting synergistic toxic effects in the aquatic environment, and hence their health risks cannot be ignored., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Dr. Rahul Kumar Singh reports financial support was provided by State Council of Science and Technology Uttar Pradesh. Dr. Rahul Kumar Singh reports financial support was provided by Institution of Eminence (IoE), BHU. Dr. Naresh Singhal reports financial support was provided by Royal Society of New Zealand Marsden Fund. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Granular activated carbon (GAC) and ion exchange resin (IXR) are widely used as adsorbents to remove PFAS from drinking water sources and effluent waste streams. However, the high cost associated with GAC and IXR generation has motivated the development of less expensive adsorbents for treatment of PFAS-impacted water. Thus, the objective of this research was to create an economically viable and sustainable PFAS adsorbent from sewage sludge. Stepwise pyrolysis at temperatures from 300 °C to 1000 °C yielded biochars whose specific surface area (SSA) and porosity increased from 41 to 148 m 2 /g, and from 0.062 to 0.193 cm 3 /g, respectively. On a per organic char basis, the SSA of the biochar was as high as 1183 m 2 /g, which is comparable to commercially-available activated carbons. The adsorption of perfluorooctane sulfonic acid (PFOS) on sludge biochar increased with increasing pyrolysis temperature, which was positively correlated with increasing porosity and SSA. When 1000 °C processed biochar was tested with a mixture of eight PFAS, preferential adsorption of longer carbon chain-length species was observed, indicating the importance of PFAS hydrophobic interactions with the biochar and the availability of a wide range of mesopores. The adsorption of each PFAS was dependent upon both chain length and head group, with longer chain-length species exhibiting greater adsorption than shorter chain-length species, along with greater adsorption of species with sulfonic acid head groups compared to their chain length counterparts with carboxylic acid head groups. These findings demonstrate that biochar derived from municipal solid waste can serve as a cost-effective and sustainable adsorbent for the removal of PFOS and PFAS mixtures from source waters. The circular economy benefits and waste reduction potential associated with the use of sewage sludge-derived biochar supports the development of a viable sludge-derived biochar for the removal of PFAS from water., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Kurt Pennell reports financial support was provided by Strategic Environmental Research and Development Program. Kurt Pennell reports financial support was provided by Woodard & Curran. Kurt Pennell reports a relationship with United States Environmental Protection Agency that includes: funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Perfluoroalkyl acids (PFAAs) are emerging pollutants that endangers food safety. Developing methods for the selective determination of trace PFAAs in complex samples remains challenging. Herein, an ionic liquid modified porous imprinted phenolic resin-dispersive filter extraction-liquid chromatography-tandem mass spectrometry (IL-PIPR-DFE-LC-MS/MS) method was developed for the determination of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in eggs. The new IL-PIPR adsorbent was prepared at room temperature, which avoids the disorder and instability of the template at high temperatures. The imprinting factor of IL-PIPR for PFOA and PFOS exceeded 7.3. DFE, combined with IL-PIPR (15 mg), was used to extract PFOA and PFOS from eggs within 15 min. The established method exhibits low limits of detection (0.01-0.02 ng/g) and high recoveries (84.7%-104.7%), which surpass those of previously reported methods. This work offers a new approach to explore advanced imprinted adsorbents for PFAAs, efficient sample pretreatment technique, and analytical method for pollutants in foods., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Competing Interests: Declaration of competing interest The author declares that he has no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Increasing levels of compounds have been detected in the environment, causing widespread pollution and posing risks to human health. However, despite their high environmental occurrence, there is very limited information regarding their toxicological effects. It is urgent to develop high-throughput screening (HTS) methods to guide toxicological studies. In this study, a receptor-ligand binding assay using an HTS system was developed to determine the binding potency of environmental pollutants on nuclear receptors. The test is conducted using a microplate reader (i.e., a 96-well plate containing various chemicals) by measuring the fluorescence polarization (FP) of a specific fluorescent probe. This assay consists of four parts: the construction and transformation of recombinant vectors, the expression and purification of the receptor protein (ligand-binding domain), receptor-probe binding, and competitive binding of chemicals with the receptor. The binding potency of two environmental pollutants, perfluorooctanesulfonic acid (PFOS) and triphenyl phosphate (TPHP), with peroxisome proliferator-activated receptor gamma (PPARγ) was determined to illustrate the assay procedure. Finally, the advantages and disadvantages of this method and its potential applications were also discussed.

Environmental remediation of per- and polyfluoroalkyl substances (PFAS) has become a significant research topic in recent years due to the fact that these materials are omnipresent, resistant to degradation and thus environmentally persistent. Unfortunately, they have also been shown to cause health concerns. PFAS are widely used in industrial applications and consumer products. Vitamin B12 (B12) has been identified as being catalytically active towards a variety of halogenated compounds such as PFAS. It has also been shown to be effective when using sulfide as a reducing agent for B12. This is promising as sulfide is readily available in the environment. However, there are many unknowns with respect to PFAS interactions with B12. These include the reaction mechanism and B12's specificity for PFAS with certain functionalization(s). In order to understand the specificity of B12 towards branched PFAS, we examined the atomistic interactions between B12 and eight different PFAS molecules using Density Functional Theory (B3LYP/cc-pVDZ). The PFAS test set included linear PFAS and their branched analogs, carboxylic acid and sulfonic acid headgroups, and aromatic and non-aromatic cyclic structures. Conformational analyses were carried out to determine the lowest energy configurations. This analysis showed that small chain PFAS such as perfluorobutanoic acid interact with the cobalt center of B12. Bulkier PFAS prefer to interact with the amine and carbonyl groups on the sidechains of the B12 ring system. Furthermore, computed complexation energies determined that, in general, branched PFAS (e.g. perfluoro-5-methylheptane sulfonic acid) interact more strongly than linear molecules (e.g. perfluorooctanesulfonic acid). Our results indicate that it may be possible to alter the interactions between B12 and PFAS by synthetically modifying the sidechains of the ring structure., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

The removal of per- and polyfluoroalkyl substances (PFAS) from drinking water is urgently needed. Here, we demonstrated high performance of vesicles on PFAS adsorption. Vesicles used in this study were enclosed amphiphile bilayers keeping their hydrophobic groups inside and their hydrophilic groups outside in water. The distribution coefficient K d of perfluorooctane sulfonic acid (PFOS) for vesicles was 5.3 × 10 5  L/kg, which is higher than that for granulated activated carbon (GAC), and K d of perfluorooctanoic acid (PFOA) for vesicles was 10 3 -10 4  L/kg. The removal efficiencies of PFOA and PFOS adsorption on DMPC vesicles were 97.1 ± 0.1% and 99.4 ± 0.2%, respectively. The adsorption behaviors of PFOA and PFOS on vesicles were investigated by changing the number of cis-double bonds in the hydrophobic chains of the vesicle constituents. Moreover, vesicles formed by membranes in the different phases were also tested. The results revealed that, when vesicles are formed of a membrane in the liquid-crystalline (liquid-like) phase, the adsorption amounts of both PFOA and PFOS increased as the cis-double bond in the hydrocarbon chains decreased, which is considered due to molecular shape similarity. When vesicles are formed of a membrane in the gel (solid-like) phase, they do not adsorb PFAS as much as in the liquid-crystalline phase, even though the hydrocarbon chains do not have any cis-double bond. Our findings demonstrate that vesicles can be utilized as PFAS adsorbents by optimizing the structure of vesicle constituents and their thermodynamical phase. Indeed, the vesicles (DMPC) were demonstrated that they can adsorb PFOA and PFOS, and be coagulated by a coagulant even in environmental water. The coagulation will enable the removal of PFOA and PFOS from the water after adsorption., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Recently, PFASs toxicity for the human immune system has become a growing concern. However, there is currently limited information on PFASs immunotoxicity beyond PFHxS, PFOA, PFOS, and PFNA. Therefore, it is urgent to close the present knowledge gap by testing a wider range of compounds. In the present study, twelve compounds were tested for a relationship between the chain-length and headgroup of a PFAS and its cytotoxic for THP-1. As such, THP-1, either as monocytes or differentiated macrophages, were exposed to PFASs in a concentration range of 0-800 μM for either 3 or 24 h. After that, cell viability and reactive oxygen species (ROS) generation were assessed using MTT and DCFH assay, respectively. PFASs' cytotoxicity is dependent on both their chain-length and headgroups. Cell viability decreased with increasing chain-length, and FTOHs displayed markedly higher toxicity than PFCAs and PFSAs. PFASs were ranked based on their calculated Relative Potency Factor. The ranking for the cytotoxicity data on monocytes appears to be 6:2 FTOH ≫ PFNA > PFDA > PFOS > PFOA >4: 2 FTOH > PFHxS = PFHxA > PFBA. For macrophages, this ranking was as follows: 6:2 FTOH >4:2 FTOH > PFOS > PFDA > PFNA > PFOA > PFHxS. The results observed for the ROS generating potential differed as FTOHs generated no ROS. Here, the ranking in monocytes was PFOA > PFNA > PFOS > PFHxS > PFDA > PFHxA = PFBS = PFBA. The ranking for macrophages was PFNA > PFDA ≥ PFOA > PFOS > PFHxA > PFHxS > PFBA = PFBS. In conclusion, the carbon chain-length and functional headgroup of a PFAS are major determinants for their toxicity to THP-1 cells. Furthermore, our study demonstrates the most potent cytotoxic effect for FTOHs in vitro, which has not been observed before to the authors' knowledge., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Victor H. Amstutz reports financial support was provided by The Netherlands Food and Consumer Product Safety Authority. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Per- and poly-fluoroalkyl substances (PFASs) are contaminants of emerging concern, yet the understanding of factors that control their leaching and release from contaminated soils remains limited. This study aimed to investigate the impact of dissolved organic carbon (DOC) on the release of PFASs-specifically, perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), and perfluorooctanoic acid (PFOA)from soils contaminated by aqueous film forming foam (AFFF). Batch aqueous leaching experiments were conducted on AFFF-contaminated soils under alkaline solution conditions (pH 9.5, 10.5, and 12) as it enhances leaching of both PFAS and DOC. Leaching of PFOS was significantly increased under alkaline conditions. Although the leaching of PFAS generally increased with pH, PFOS appeared to be more retained under the very alkaline pH conditions used in this study. At the same solution pH, leaching of PFOS and DOC was less in Ca(OH) 2 than in NaOH. The retention of PFOS under these conditions may be attributable to the shielding of the negative charge of the soil components and colloids (e.g., DOC and clay minerals) in the leachates and/or the screening of negative charges on head groups of PFOS due to the high concentration of divalent cations. Solution chemistry affected desorption of PFOS more than PFHxS and PFOA. The study highlights that the influence of DOC on PFAS leaching and transport can be very complex, and depends on leachate chemistry (e.g., pH and cation type), PFAS chemistry, the magnitude of PFAS contamination and factors that influence the solid:liquid partitioning of organic carbon in soil., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Shervin Kabiri reports financial support was provided by Australian Research Council. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Owing to the persistence and increasingly stringent regulations of perfluoroalkyl substances (PFAS), it is necessary to improve their adsorption capacities using activated carbon (AC). However, their adsorption capacities are suppressed by dissolved organic matter (DOM). In this study, two ACs modified with organic silicon (C-OS) and inorganic silicon (C-IS) were synthesized and used for the adsorption of PFAS in raw water (RW). The results showed that the PFAS adsorption capacity of C-IS was much less influenced by DOM than that of the original AC (C-virgin). In RW, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) adsorption capacities on C-IS were 15.08 and 3.65 times higher than those on C-virgin, respectively. DOM had less influence on the PFOA and PFOS adsorption kinetics of C-IS than C-OS and C-virgin. Under multi-PFAS condition, C-IS also exhibited slower desorption of short-chain PFAS and breakthrough in batch and column tests, respectively. Characterization of the ACs before and after adsorption and independent gradient modelling indicated that hydrogen bond interactions between the O-Si of C-IS and the -COOH or -CSO 3 H groups of PFAS contributed to PFAS adsorption. Density functional theory calculations demonstrated that the adsorption energy of C-IS was much lower than that of C-OS and C-virgin. The arrangement of PFAS molecules on C-OS was chaotic owing to the hydrophobic siloxane chain, whereas the arrangement of PFAS on C-IS was orderly in multi-layer or semi-micelle status and more favorable to PFAS adsorption. This study provides a new strategy for avoiding adverse effects of DOM on PFAS adsorption., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The transport of PFOS and PFOA in well-characterized sand was investigated for relatively low water saturations. An instrumented column was used for some experiments to provide real-time in-situ monitoring of water saturation and matric potential. The results showed that water saturations and matric potentials varied minimally during the experiments. Flow rates were monitored continuously and were essentially constant. These results demonstrate that surfactant-induced flow and other nonideal hydraulic processes did not materially impact PFAS transport for the experiment conditions. Air-water interfacial adsorption was demonstrated to provide the great majority of retention for PFOS and PFOA. Retention was significantly greater at the lower water saturations (0.35-0.45) compared to the higher saturations (∼0.66) for both PFAS, due to the larger extant air-water interfacial areas. Retardation factors were 5 and 3-times greater at the lower water saturations for PFOS and PFOA, respectively. Early breakthrough was observed for the PFAS but not for the non-reactive tracers at the lower water saturations, indicating the possibility that air-water interfacial adsorption was rate-limited to some degree. Independently determined retention parameters were used to predict retardation factors for PFOS and PFOA, which were similar to the measured values in all cases. The consistency between the predicted and measured values indicates that PFAS retention was accurately represented. In addition, air-water interfacial adsorption coefficients measured from the transport experiments were consistent with independently measured equilibrium-based values. Based on these results, it appears that the air-water interfacial adsorption processes mediating the magnitude of PFOS and PFOA retention under lower water-saturation conditions are consistent with those for higher water saturations. This provides some confidence that our understanding of PFAS retention obtained from work conducted at higher water saturations is applicable to lower water saturations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Perfluorooctanesulfonate (PFOS), a toxic anionic perfluorinated surfactant, exhibits variable electrostatic adsorption mechanisms on charge-regulated minerals depending on solution hydrochemistry. This work explores the interplay of multicomponent interactions and surface charge effects on PFOS adsorption to goethite surfaces under flow-through conditions. We conducted a series of column experiments in saturated goethite-coated porous media subjected to dynamic hydrochemical conditions triggered by step changes in the electrolyte concentration of the injected solutions. Measurements of pH and PFOS breakthrough curves at the outlet allowed tracking the propagation of multicomponent reactive fronts. We performed process-based reactive transport simulations incorporating a mechanistic network of surface complexation reactions to quantitatively interpret the geochemical processes. The experimental and modeling outcomes reveal that the coupled spatio-temporal evolution of pH and electrolyte fronts, driven by the electrostatic properties of the mineral, exerts a key control on PFOS mobility by determining its adsorption and speciation reactions on goethite surfaces. These results illuminate the important influence of multicomponent transport processes and surface charge effects on PFOS mobility, emphasizing the need for mechanistic adsorption models in reactive transport simulations of ionizable PFAS compounds to determine their environmental fate and to perform accurate risk assessment.

PER: and polyfluorinated alkyl substances, especially perfluorooctanoic acid and perfluorooctane sulfonic acid (PFOX), have attracted considerable attention lately because of their widespread occurrence in aquatic environment and potential biological toxicity to animals and human beings. The development of economical, efficient, and engineerable adsorbents for removing PFOX in water has become one of the research focuses. This review summarized the recent progress on natural mineral and industrial solid based adsorbent (NM&ISW-A) and removal mechanisms concerning PFOX onto NM&ISW-A, as well as proposed the current challenges and future perspectives of using NM&ISW-A for PFOX removal in water. Kaolinite and montmorillonite are usually used as model clay minerals for PFOX removal, and have been proved to adsorb PFOX by ligand exchange and electrostatic attraction. Fe-based minerals, such as goethite, magnetite, and hematite, have better PFOX adsorption capacity than clay minerals. The adsorbent prepared from industrial solid waste by high temperature roasting has great potential application prospects. Fabricating nanomaterials, amination modification, surfactant modification, fluorination modification, developing versatile composites, and designing special porous structure are beneficial to improve the adsorption performance of PFOX onto NM&ISW-A by enhancing the specific surface area, positive charge, and hydrophobicity. Electrostatic interaction, hydrophobic interaction, hydrogen bond, ligand and ion exchange, and self-aggregation (formation of micelle or hemimicelle) are the main adsorption mechanisms of PFOX by NM&ISW-A. Among them, electrostatic and hydrophobic interactions play a considerable role in the removal of PFOX by NM&ISW-A. Therefore, NM&ISW-A with electrostatic functionalities and considerable hydrophobic segments enables rapid, efficient, and high-capacity removal of PFOX. The future directions of NM&ISW-A for PFOX removal include the preparation and regeneration of engineerable NM&ISW-A, the development of coupling technology for PFOX removal based on NM&ISW-A, the in-depth research on adsorption mechanism of PFOX by NM&ISW-A, as well as the development of NM&ISW-A for PFOX alternatives removal. This review paper would be helpful the comprehensive understanding of NM&ISW-A potential for PFOX removal and the PFOX removal mechanisms, and identifies the gaps for future research and development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Background: The family of perfluoroalkyl and polyfluoroalkyl substances (PFAS) raised concern for their proven bioaccumulation and persistence in the environment and animals as well as for their hazardous health effects. As a result, new congeners of PFAS have rapidly replaced the so-called "old long-chain PFAS" (mainly PFOA and PFOS), currently out-of-law and banned by most countries. These compounds derive from the original structure of "old long-chain PFAS", by cutting or making little conformational changes to their structure, thus obtaining new molecules with similar industrial applications. The new congeners were designed to obtain "safer" compounds. Indeed, old-long-chain PFAS were reported to exert thyroid disruptive effects in vitro, and in vivo in animals and humans. However, shreds of evidence accumulated so far indicate that the "restyling" of the old PFAS leads to the production of compounds, not only functionally similar to the previous ones but also potentially not free of adverse health effects and bioaccumulation. Studies aimed at characterizing the effects of new-PFAS congeners on thyroid function indicate that some of these new-PFAS congeners showed similar effects., Purpose: The present review is aimed at providing an overview of recent data regarding the effects of novel PFAS alternatives on thyroid function., Results and Conclusions: An extensive review of current legislation and of the shreds of evidence obtained from in vitro and in vivo studies evaluating the effects of the exposure to novel PFOA and PFOS alternatives, as well as of PFAS mixture on thyroid function will be provided., (© 2024. The Author(s).)

Due to their widespread production and known environmental contamination, the need for the detection and remediation of per- and polyfluoroalkyl substances (PFAS) has grown quickly. While destructive thermal treatment of PFAS at low temperatures (e.g., 200-500 °C) is of interest due to lower energy and infrastructure requirements, the range of possible degradation products remains underexplored. To better understand the low temperature decomposition of PFAS species, we have coupled gas-phase infrared spectroscopy with a multivariate curve resolution (MCR) analysis and a database of high-resolution PFAS infrared reference spectra to characterize and quantify a complex mixture resulting from potassium perfluorooctanesulfonate (PFOS-K) decomposition. Beginning at 375 °C, nine prevalent decomposition products (namely smaller perfluorocarbon species) are identified and quantified., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

There is considerable interest in addressing soils contaminated with per- and polyfluoroalkyl substances (PFAS) because of the PFAS in the environment and associated health risks. The neutralization of PFAS in situ is challenging. Consequently, mobilizing the PFAS from the contaminated soils into an aqueous solution for subsequent handling has been pursued. Nonetheless, the efficiency of mobilization methods for removing PFAS can vary depending on site-specific factors, including the types and concentrations of PFAS compounds, soil characteristics. In the present study, the removal of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) from artificially contaminated soils was investigated in a 2D laboratory setup using electrokinetic (EK) remediation and hydraulic flushing by applying a hydraulic gradient (HG) for a duration of 15 days. The percent removal of PFOA by EK was consistent (∼80%) after a 15-day treatment for all soils. The removal efficiency of PFOS by EK significantly varied with the OM content, where the PFOS removal increased from 14% at 5% OM to 60% at 50% OM. With HG, the percent removal increased for both PFOA and PFOS from about 20% at 5% OM up to 80% at 75% OM. Based on the results, the mobilization of PFAS from organic soil would be appropriate using both hydraulic flushing and EK considering their applicability and advantages over each other for site-specific factors and requirements., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The adsorption of per- and polyfluoroalkyl substances (PFAS), such as perfluorooctane sulfonate (PFOS), is currently a critical issue in the environmental domain, yet it is not fully understood. Diamane, as a stable monolayer adsorbent, has garnered significant research interest. Defects and strain are reported to play a crucial role in regulating its electronic structure. In this study, we employ density functional theory (DFT) calculations to investigate the adsorption of PFOS on both pristine and nitrogen-vacancy (N-V) defected diamane, respectively. Additionally, we systematically examine the effects of strain in diamane along both the a- and b-directions (two directions of a monolayer) on PFOS adsorption. This analysis involves studying the adsorption energy (E ads ), electron transfer, and the partial density of states. Finally, we propose the synergistic effects of N-V defects and compression strain in diamane, which enhance PFOS adsorption. Diamane is considered a promising candidate for PFOS sensing or capture., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The ubiquitousness of per- and polyfluoroalkyl substances (PFAS) is a big concern and PFAS remediation is urgently needed such as via degradation. While previous studies have explored ultrasonic degradation of PFAS, work evaluating the operational parameters is rare, especially concerning real wastes such as aqueous film-forming foam (AFFF) and foam fractionate (FF). This study investigates the key operational parameters affecting the degradation efficiency of PFAS, encompassing ultrasonication frequency (580-1144 kHz), power intensity (125-187.5 W), initial concentration (0.08-40 ppm), treatment duration (0.5-3 h), sample volume (100-500 mL), and PFAS structure (perfluorooctanoic acid or PFOA; perfluorooctane sulfonate or PFOS; 6:2 fluorotelomer sulfonate or 6:2 FTS). The defluorination kinetics is different from the removal/degradation kinetics due to the generation of degradation intermediates, suggesting the complex degradation mechanism, which should be evaluated to close the mass balance effectively. Notably, the optimised ultrasonic system achieves ∼125%/∼115% defluorination in AFFF/FF example wastes (compared to ∼65%/∼97% removal) despite their complex composition and the involvement of total oxidizable precursor (TOP) assay. In the meantime, a few new PFAS are detected in the post-treatments, including perfluorohexane sulfonic acid (PFHxS) and 10:2 fluorotelomer sulfonate (10:2 FTS) in the AFFF, and perfluorooctane sulfonamide (FOSA) and 8:2 fluorotelomer sulfonate (8:2 FTS) in the FF, again suggesting the complex degradation mechanism. Overall, ultrasonication is effective to degrade PFAS real example wastes, advancing its potential for scale-up applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Herein, Ce-doped CoFe layered double hydroxide (LDH), noted as CoCeFe ternary LDH, was prepared using the co-precipitation route. Prosperous synthesis of CoFe LDH and successful partial replacement of iron cations with cerium cations in CoCeFe ternary LDH were confirmed by X-ray diffraction patterns, energy-dispersive X-ray spectroscopy, and elemental dot-mapping images. Nanosheet morphology was recognized for both CoFe LDH and CoCeFe ternary LDH from scanning electron microscopy and transmission electron microscopy micrographs. In the following, a dispersive solid phase extraction (DSPE) method was developed using the synthesized CoCeFe ternary LDH as a sorbent for extracting perfluorooctanesulfonic acid (PFOS) from wastewater samples. For the selective analysis of PFOS, high-performance liquid chromatography-tandem mass spectroscopy (HPLC-MS/MS) in multiple reaction monitoring mode was used. Analytical parameters such as the limit of detection equal to 0.02 μg/L, with a linear range of 0.05-300 μg/L, the limit of quantification equal to 0.05 μg/L, and an enrichment factor equal to 23.3 were achieved for PFOS at the optimized condition (sorbent: 5 mg of CoCeFe ternary LDH, eluent type and volume: 150 μL mobile phase, pH: 3, adsorption time: 3 min, and desorption time: 5 min). The developed strategy for the analysis of PFOS was tested in real wastewater samples, including copper mine and petrochemical wastewater. The amount of analytes in real samples was calculated using the standard addition method, and good relative recovery in the range of 86%-105% was obtained. The main novelty of this research is the application of CoCeFe ternary LDH to extract the PFOS from wastewater using the DSPE method for determination by HPLC-MS/MS., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Per- and polyfluoroalkyl substances (PFAS) pose a significant threat to the environment due to their persistence, ability to bioaccumulate, and harmful effects. Methods to quantify PFAS rapidly and effectively are essential to analyze and track contamination, but measuring PFAS down to the ultralow regulatory levels is extremely challenging. Here, we describe the development of a low-cost sensor that can measure a representative PFAS, perfluorooctanesulfonic acid (PFOS), at the parts per quadrillion (ppq) level within 5 min. The method combines the ability of PFOS to bind to silver nanoparticles (AgNPs) embedded within a fluorine-rich Ti 3 C 2 -based multilayered MXene, which provides a large surface area and accessible binding sites for direct impedimetric detection. Fundamentally, we show that MXene-AgNPs are capable of binding PFOS and other long-chain PFAS compounds, though the synergistic action of AgNPs and MXenes via electrostatic and F-F interactions. This binding induced concentration-dependent changes in the charge-transfer resistance, enabling rapid and direct quantification with extremely high sensitivity and no response to interferences. The sensor displayed a linear range from 50 ppq to 1.6 ppt (parts per trillion) with an impressively low limit of detection of 33 ppq and a limit of quantification of 99 ppq, making this sensor a promising candidate for low-cost screening of the PFAS content in water samples, using a simple and inexpensive procedure.

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

Recent research has found biochar to be a cost-effective adsorbent for removal of perfluoroalkyl substances in water. To promote cleaner production and sustainable waste management, this study explored the potential to produce activated biochars by co-pyrolyzing sawdust with iron-rich biosolids and polyaluminum sludge. The maximum capacity to adsorb perfluorooctanesulfonic acid (PFOS) reached 27.2 mg g -1 with biosolids-activated biochar and 19.2 mg g -1 with aluminum sludge-activated biochar, compared to 6.2 mg g -1 with sawdust biochar. The increased adsorption capacities were attributed to electrostatic interactions between the anionic PFOS and metal functionalities on the biochar surface. In contrast, hydrophobic interaction was the dominant adsorption mechanism of sawdust biochar. The presence of dissolved organic matter at 5-50 mg L -1 was found to inhibit adsorption of PFOS in water, while pH as low as 3.0 and sodium chloride concentrations up to 100 mM enhanced removal of PFOS by all the three adsorbents. In batch adsorption tests at environmentally relevant PFOS dosages and adsorbent dosage of 0.25 g L -1 , the biosolids-sawdust biochar and Al sludge-sawdust biochar removed 71.4% and 66.9% of PFOS from drinking water and 77.9% and 87.9% of PFOS from filtrate of sludge digestate, respectively. The biosolids-sawdust biochar additionally removed Fe, although the Al sludge-sawdust biochar released Al into the alkaline drinking water and filtrate. Overall, this study proved co-pyrolyzing sawdust and Fe-rich biosolids to be an effective approach to activate sawdust biochar for enhanced removal of PFOS while recycling wastewater treatment residuals and sawdust., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Electrocatalytic destruction of per- and polyfluoroalkyl substances (PFAS) is an emerging approach for treatment of PFAS-contaminated water. In this study, a systematic ab initio investigation of PFAS adsorption on Ni, a widely used electrocatalyst, was conducted by means of dispersion-corrected Density Functional Theory (DFT) calculations. The objective of this investigation was to elucidate the adsorption characteristics and charge transfer mechanisms of different PFAS molecules on Ni surfaces. PFAS adsorption on three of the most thermodynamically favorable Ni surface facets, namely (001), (110), and (111), was investigated. Additionally, the role of PFAS chain length and functional group was studied by comparing the adsorption characteristics of different PFAS compounds, namely perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorobutanesulfonic acid (PFBS), and perfluorobutanoic acid (PFBA). For each PFAS molecule-Ni surface facet pair, different adsorption configurations were considered. Further calculations were carried out to reveal the effect of solvation, pre-adsorbed atomic hydrogen (H), and surface defects on the adsorption energy. Overall, the results revealed that the adsorption of PFAS on Ni surfaces is energetically favorable, and that the adsorption is primarily driven by the functional groups. The presence of preadsorbed H and the inclusion of solvation produced less exothermic adsorption energies, while surface vacancy defects showed mixed effects on PFAS adsorption. Taken together, the results of this study suggest that Ni is a promising electrocatalyst for PFAS adsorption and destruction, and that proper control for the exposed facets and surface defects could enhance the adsorption stability., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Ahmed Abokifa reports financial support was provided by National Alliance for Water Innovation. Brian Chaplin reports financial support was provided by National Alliance for Water Innovation. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

UV/Fe 3+ and persulfate are two promising advanced oxidative degradation systems for in situ remediation of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), yet a lack of comprehensive understanding of the degradation mechanisms. For the first time, we used density functional theory (DFT) to calculate the entire reaction pathways of the degradation of PFOA/PFOS in water by UV/Fe 3+ and persulfate. In addition, we have deeply explored the different attack pathways driven by •OH and SO 4 -• , and found that SO 4 -• determines PFOA/PFOS to obtain PFOA/PFOS free radicals through single electron transfer to initiate the degradation reaction, while •OH determines the speed of PFOA/PFOS degradation reaction. Both degradation reactions were thermodynamically advantageous and kinetically feasible under calculated conditions. Based on the thermodynamic data, persulfate was found to be more favorable for the advanced oxidative degradation of Perfluorinated compounds (PFCs). Moreover, for SO 4 -• and •OH co-existing in the persulfate system, pH will affect the presence and concentration of these two types of free radicals, and low pH is not necessary for the degradation of PFOA/PFOS in the persulfate system. These results can considerably advance our understanding of the PFOA/PFOS degradation process in advanced oxidation processes (AOPs), which is driven by •OH and SO 4 -• . This study provides a DFT calculation process for the mechanism calculation of advanced oxidation degradation of other types of PFCs pollutants, hoping to elucidate the future development of PFCs removal. Further research should focus on determining the advanced oxidation degradation pathways of other types of PFCs, to support the development of computational studies on the advanced oxidation degradation of PFCs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

A new adsorbent based on commercial granular activated carbon (GAC) and loaded with Cu(II) (GAC-Cu) was prepared to enhance the adsorption capacity of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). The surface area (SA) and pore volume of GAC-Cu decreased by ∼15% compared to those of pristine GAC. The scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) and leaching test results indicated that, compared with GAC, the Cu atomic ratio and Cu amount in GAC-Cu increased by 2.91 and 2.43 times, respectively. The point of zero charge (PZC) measured using a salt addition method obtained a pH of 6.0 (GAC) and 5.0 (GAC-Cu). According to the isotherm models obtaining highest coefficient of determination (R 2 ), GAC-Cu exhibited a 20.4% and 35.2% increase for PFOA and PFOS in maximum uptake (q m ), respectively, compared to those of GAC. In addition, the adsorption affinity (b) for GAC-Cu increased by 1045% and 175% for PFOA and PFOS, respectively. The pH effect on the adsorption capacity of GAC-Cu was investigated. The uptake of PFOA and PFOS decreased with an increase in pH for both GAC and GAC-Cu. GAC-Cu exhibited higher uptake than GAC at pH 6 and 7, but no enhanced uptake was observed at pH 4.0, 5.0, and 8.5. Therefore, ligand interaction was effective at weak acid or neutral pH., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant posing a risk in environmental persistence, bioaccumulation and biotoxicity. This study was to reach a comprehensive and deeper understanding of PFOS elimination in a UV 254 photolytic treatment with the co-presence of Fe 2+ and nitrilotriacetic acid trisodium salt (NTA). PFOS defluorination was noticeably enhanced in the UV/Fe 2+ -NTA treatment compared with UV/NTA, UV/Fe 2+ and our previously studied UV/Fe 3+ treatments. UV-vis, FTIR, and UPLC/MS-MS results indicated the formation of PFOS-Fe 2+ -NTA complex in PFOS, Fe 2+ and NTA mixture. The transition energy gap of PFOS-Fe 2+ -NTA decreased below the excitation energy supplied by UV 254 irradiation, corresponding with red shift appearing in UV-vis scanning spectrum. This favored intramolecular electron transfer from Fe 2+ -NTA to PFOS under UV 254 irradiation to form electron-accepting PFOS. Molecular electrostatic potential and atom charge distribution analyses suggested electron density rearrangement and perturbation in the perfluorinated carbon chain of electron-accepting PFOS, leading to the decrease in bond dissociation energies. Intermediate products detection suggested the parallel defluorination pathways of PFOS desulfonation, middle carbon chain scission and direct C-F cleavage. NTA exhibited crucial functions in the UV/Fe 2+ -NTA treatment by holding Fe 2+ /Fe 3+ in soluble form as a chelant and favoring water activation to generate hydrated electrons (e aq - ) under UV irradiation as a photosensitizer. Fe 2+ acting as the conduit for electron transfer and the bridge of PFOS anion and NTA was thought functioning best at 200 µM in this study. The degree of UV/Fe 2+ -NTA -synergized PFOS defluorination also depended on e aq - yield and UV 254 photon flux. The structure dependence on the electron transfer process of PFOS and PFOA was explored incorporating molecular structure descriptors. Because of possessing greater potential to acquire electrons or less likeliness to donate its electrons than PFOA, PFOS exhibited faster defluorination kinetics in the published "reduction treatments" than "oxidation" ones. Whereas, PFOA defluorination kinetics were at similar level in both "reduction" and "oxidation" treatments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Perfluorooctanesulfonate (PFOS) has become a major concern due to its widespread occurrence in the environment and severe toxic effects. In this study, we investigate PFOS sorption on goethite surfaces under different water chemistry conditions to understand the impact of variable groundwater chemistry. Our investigation is based on multiple lines of evidence, including (i) a series of sorption experiments with varying pH, ionic strength, and PFOS initial concentration, (ii) IR spectroscopy analysis, and (iii) surface complexation modeling. PFOS was found to bind to goethite through a strong hydrogen-bonded (HB) complex and a weaker outer-sphere complex involving Na + coadsorption (OS-Na + ). The pH and ionic strength of the solution had a nontrivial impact on the speciation and coexistence of these surface complexes. Acidic conditions and low ionic strength promoted hydrogen bonding between the sulfonate headgroup and protonated hydroxo surface sites. Higher electrolyte concentrations and pH values hindered the formation of strong hydrogen bonds upon the formation of a ternary PFOS-Na + -goethite outer-sphere complex. The findings of this study illuminate the key control of variable solution chemistry on PFOS adsorption to mineral surfaces and the importance to develop surface complexation models integrating mechanistic insights for the accurate prediction of PFOS mobility and environmental fate.

Chlorinated polyfluorooctane ether sulfonate (6:2 Cl-PFESA), hydrogenated polyfluorooctane ether sulfonate (6:2 H-PFESA), and chlorinated polyfluorooctanesulfonate (Cl-PFOS) share structural similarities with the regulated perfluorooctanesulfonate (PFOS), but their toxic potential is rarely known. Here, the thyroid disrupting potential of these four compounds in zebrafish larvae has been comparably investigated. PFOS, Cl-PFOS, and 6:2 Cl-PFESA were accumulated in the larvae at similar levels, approximately 1.3-1.6 times higher than 6:2 H-PFESA. Additionally, PFOS, Cl-PFOS, and 6:2 Cl-PFESA exhibited stronger disruption than 6:2 H-PFESA on genetic regulation, particularly concerning thyroid hormone (TH) activation and action and on TH homeostasis in both free and total forms of thyroxine (T4) and 3,5,3'-triiodothyronine (T3). These results indicate that chlorination or oxygen insertion does not substantially alter the thyrotoxicity of PFOS, but hydrogenation mitigates it. Molecular docking analysis and the luciferase reporter gene assay provided mechanistic perspectives that the PFOS-like substances could competitively replace THs to bind with TH plasma and membrane transporters, thereby disrupting TH transport and action, respectively. Moreover, they are also potent to disrupt TH synthesis and activation through Na + /K + -dependent transport of I - or competitive binding to the sites of deiodinases.

Acidimicrobium sp. strain A6 is a recently discovered autotrophic bacterium that is capable of oxidizing ammonium while reducing ferric iron and is relatively common in acidic iron-rich soils. The genome of Acidimicrobium sp. strain A6 contains sequences for several reductive dehalogenases, including a gene for a previously unreported reductive dehalogenase, rdhA. Incubations of Acidimicrobium sp. strain A6 in the presence of perfluorinated substances, such as PFOA (perfluorooctanoic acid, C 8 HF 15 O 2 ) or PFOS (perfluorooctane sulfonic acid, C 8 HF 17 O 3 S), have shown that fluoride, as well as shorter carbon chain PFAAs (perfluoroalkyl acids), are being produced, and the rdhA gene is expressed during these incubations. Results from initial gene knockout experiments indicate that the enzyme associated with the rdhA gene plays a key role in the PFAS defluorination by Acidimicrobium sp. strain A6. Experiments focusing on the defluorination kinetics by Acidimicrobium sp. strain A6 show that the defluorination kinetics are proportional to the amount of ammonium oxidized. To explore potential applications for PFAS bioremediation, PFAS-contaminated biosolids were augmented with Fe(III) and Acidimicrobium sp. strain A6, resulting in PFAS degradation. Since the high demand of Fe(III) makes growing Acidimicrobium sp. strain A6 in conventional rectors challenging, and since Acidimicrobium sp. strain A6 was shown to be electrogenic, it was grown in the absence of Fe(III) in microbial electrolysis cells, where it did oxidize ammonium and degraded PFAS., (Copyright © 2024. Published by Elsevier Inc.)

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) present in various water sources have raised a serious concern on their health risk worldwide. Anion exchange is known to be one of the effective treatment methods but the resin properties suitable for theses contaminants have not been fully understood. We examined four commercially available anion exchange resins with different properties (DIAION™ PA312, HPA25M, UBA120, and WA30) and one polymer-based adsorbent (HP20), for their PFOA and PFOS removal in the batch experiment. All or a part of the selected resins were further characterized for their functional group, surface morphology and pore size distribution. The 72 h batch experiment with the 100 mg/L PFOA or PFOS in the laboratory pure water matrix showed a superior capacity of the strong base anion exchange resins, the porous-type HPA25M and PA312, and the gel-type UBA120, for PFOA removal (92.6-97.9%). Among those resins, the high porous HPA25M was suggested most effective due to its remarkably high reaction rate and effectiveness to PFOS (99.9%). In the groundwater matrix, however, the performance of the those anion exchange resins was generally suppressed, causing up to 71% decrease in their removal rates. The least matrix impact was observed for PFOS removal by HPA25M, which indicated the resin's high selectivity to the contaminant. The physiochemical analysis indicated that the presence of relatively large pores (1 nm-10 nm) over HPA25M played an important role in the PFAS removal., Competing Interests: Declaration of competing interest Two authors are employees of a company that manufactures the adsorbents examined in this study, which may pose a conflict of interest. However, all of the data analysis and interpretation was conducted independently of the company and the authors have disclosed this potential conflict of interest., (Copyright © 2023. Published by Elsevier Ltd.)

Perfluorooctane sulfonate (PFOS) was widely used in industrial applications before it was listed as a persistent organic pollutant by the Conference of the Parties in the Stockholm Convention in 2009. Although the potential toxicity of PFOS has been studied, its toxic mechanisms remain largely undefined. Here, we investigated novel hub genes and pathways affected by PFOS to gain new conceptions of the toxic mechanisms of PFOS. Reduced body weight gain and abnormal ultra-structures in the liver and kidney tissues were spotted in PFOS-exposed rats, indicating successful establishment of the PFOS-exposed rat model. The transcriptomic alterations of blood samples upon PFOS exposure were analysed using RNA-Seq. GO analysis indicates that the differentially expressed gene-enriched GO terms are related to metabolism, cellular processes, and biological regulation. Kyoto encyclopaedia of gene and genomes (KEGG) and gene set enrichment analysis (GSEA) were conducted to identify six key pathways: spliceosome, B cell receptor signalling pathway, acute myeloid leukaemia, protein processing in the endoplasmic reticulum, NF-kappa B signalling pathway, and Fc gamma R-mediated phagocytosis. The top 10 hub genes were screened from a protein-protein interaction network and verified via quantitative real-time polymerase chain reaction. The overall pathway network and hub genes may provide new insights into the toxic mechanisms of PFOS exposure states., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Hydrophobic interaction is a prevalent sorption mechanism of poly- and perfluoroalkyl substances (PFAS) in natural and engineered environments. In this study, we combined quartz crystal microbalance with dissipation (QCM-D), atomic force microscope (AFM) with force mapping, and molecular dynamics (MD) simulation to probe the molecular behavior of PFAS at the hydrophobic interface. On a CH 3 -terminated self-assembled monolayer (SAM), perfluorononanoic acid (PFNA) showed ∼2-fold higher adsorption than perfluorooctane sulfonate (PFOS) that has the same fluorocarbon tail length but a different head group. Kinetic modeling using the linearized Avrami model suggests that the PFNA/PFOS-surface interaction mechanisms can evolve over time. This is confirmed by AFM force-distance measurements, which shows that while the adsorbed PFNA/PFOS molecules mostly lay flat, a portion of them formed aggregates/hierarchical structures of 1-10 nm in size after lateral diffusion on surface. PFOS showed a higher affinity to aggregate than PFNA. Association with air nanobubbles is observed for PFOS but not PFNA. MD simulations further showed that PFNA has a greater tendency than PFOS to have its tail inserted into the hydrophobic SAM, which can enhance adsorption but limit lateral diffusion, consistent with the relative behavior of PFNA/PFOS in QCM and AFM experiments. This integrative QCM-AFM-MD study reveals that the interfacial behavior of PFAS molecules can be heterogeneous even on a relatively homogeneous surface., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Ning Dai reports financial support was provided by National Science Foundation. Tashfia M. Mohona reports financial support was provided by National Science Foundation., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The pH-dependent soil-water partitioning of six perfluoroalkyl substances (PFASs) of environmental concern (PFOA, PFDA, PFUnDA, PFHxS, PFOS and FOSA), was investigated for 11 temperate mineral soils and related to soil properties such as organic carbon content (0.2-3%), concentrations of Fe and Al (hydr)oxides, and texture. PFAS sorption was positively related to the perfluorocarbon chain length of the molecule, and inversely related to solution pH for all substances. The negative slope between log K d and pH became steeper with increasing perfluorocarbon chain length of the PFAS (r 2  = 0.75, p ≤ 0.05). Organic carbon (OC) alone was a poor predictor of the partitioning for all PFASs, except for FOSA (r 2  = 0.71), and the OC-normalized PFAS partitioning, as derived from organic soil materials, underestimated PFAS sorption to the soils. Multiple linear regression suggested sorption contributions (p ≤ 0.05) from OC for perfluorooctane sulfonate (PFOS) and FOSA, and Fe/Al (hydr)oxides for PFOS, FOSA, and perfluorodecanoate (PFDA). FOSA was the only substance under study for which there was a statistically significant correlation between its binding and soil texture (silt + clay). To predict PFAS sorption, the surface net charge of the soil organic matter fraction of all soils was calculated using the Stockholm Humic Model. When calibrated against charge-dependent PFAS sorption to a peat (Oe) material, the derived model significantly underestimated the measured K d values for 10 out of 11 soils. To conclude, additional sorbents, possibly including silicate minerals, contribute to the binding of PFASs in soil. More research is needed to develop geochemical models that can accurately predict PFAS sorption in soils., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Zero-valent iron (Fe) is commonly employed as an additive for the mechanochemical destruction (MCD) of organic pollutants. The poly- and perfluoroalkyl substances (e.g., perfluorooctane sulfonate, PFOS) are a class of toxic environmental pollutants that are difficult to effectively degrade due to their thermodynamic and chemical stability. In this study, magnetite (Fe 3 O 4 ) was applied to improve the milling performance of Fe to PFOS and its promoting mechanisms were emphatically explored. The desulfurization rate was in ahead of the defluorination rate because the C-S bond is less stable than the C-F bonds in PFOS. Fe 3 O 4 had an excellent reinforcement effect on the milling performance of Fe, which was mainly through accelerating the electron transfer as a conductor, reacting with Fe to produce FeO, and facilitating the formation of HO ● . During the MCD of PFOS with Fe/Fe 3 O 4 as an additive, HO ● played a dominant role in the defluorination process (accounting for >67%). After the elimination of sulfonate group (-SO 3 - ), the produced radical (C 7 F 15 CF 2 ● ) continued to react through two main pathways: one was the stepwise defluorination after hydrogenation, and the other one was oxidation reaction after alcoholization to yield the corresponding aldehydes and carboxylic acids. The optimum Fe fraction (M Fe ) was 30%, and air atmosphere was more effective than oxygen and nitrogen conditions. This study helps to comprehensively understand the role of Fe 3 O 4 in defluorination and fills the gap of Fe/Fe 3 O 4 application in the MCD of PFASs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Persistent organic pollutants (POPs) exist widely in the environment and place significant impact on human health by bioaccumulation. Efficient recognition of POPs and their removal are highly challenging tasks because their specific structures interact often very weakly with the capture materials. Herein, a molecular nanocage ( 1 ) is studied as an efficient sensing and sorbent material for POPs, which is demonstrated by a representative and stable perfluorooctane sulfonate (PFOS) substrate containing a hydrophilic sulfonic group and a hydrophobic fluoroalkyl chain. A highly sensitive and unusual turn-on fluorescence response within 10 s and a 97% total removal of PFOS from water in 20 min have been achieved owing to the strong host-guest interactions between 1 and PFOS. The binding constant of 1 to PFOS is 2 orders of magnitude higher than state-of-the-art adsorbents for PFOS and thus represents a new benchmark material for the recognition and removal of PFOS. The host-guest interaction has been elucidated by solid-state NMR spectroscopy and single-crystal X-ray diffraction, which provide key insights at a molecular level for the design of new advanced sensing/sorbent materials for POPs.

Per-/polyfluoroalkyl substances (PFASs) contamination has caused worldwide health concerns, and increased demand for effective elimination strategies. Herein, we developed a new indole derivative decorated with a hexadecane chain and a tertiary amine center (named di-indole hexadecyl ammonium, DIHA), which can form stable nanospheres (100-200 nm) in water via supramolecular assembly. As the DIHA nanospheres can induce electrostatic, hydrophobic and van der Waals interactions (all are long-ranged) that operative cooperatively, in addition to the nano-sized particles with large surface area, the DIHA nanocomposite exhibited extremely fast adsorption rates (in seconds), high adsorption capacities (0.764-0.857 g g -1 ) and selective adsorption for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), outperformed the previous reported high-end PFASs adsorbents. Simultaneously, the DIHA nanospheres can produce hydrated electron (e aq - ) when subjected to UV irradiation, with the virtue of constraining the photo-generated e aq - and the adsorbed PFOA/PFOS molecules entirely inside the nanocomposite. As such, the UV/DIHA system exhibits extremely high degradation/defluorination efficiency for PFOA/PFOS, even under ambient conditions, especially with the advantages of low chemical dosage requirement (μM level) and robust performance against environmental variables. Therefore, it is a new attempt of using supramolecular approach to construct an indole-based nanocomposite, which can elegantly combine adsorption and degradation functions. The novel DIHA nanoemulsion system would shed light on the treatment of PFAS-contaminated wastewater., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Xin Jin, Cheng Gu has patent licensed to ZL202010353919.4., (Copyright © 2022. Published by Elsevier Ltd.)

Volatile per- and polyfluoroalkyl substances (PFAS) are detected in various consumer goods, raising concerns over environmental fate and human exposure. Volatile PFAS are commonly analyzed by gas chromatography-chemical ionization-mass spectrometry. Mass-labeled standards are used for quantitative analysis of volatile PFAS and to ensure quality control. However, mass-labeled fluorotelomer alcohol (FTOH) analyzed in positive chemical ionization produces signals corresponding to nonlabeled (native) FTOH ions, resulting in false positives. This observation was attributed to deuterium or hydrogen abstraction of mass-labeled standards. Deuterium abstraction of deuterated standards, including d 4 -4:2 FTOH, 13 C 2 - d 2 -6:2 FTOH, 13 C 2 - d 2 -10:2 FTOH, and hydrogen abstraction of 13 C-labeled standard 13 C 2 -8:2 FTOH are ionization artifacts that yielded responses for native FTOH m / z values. False positives for native (nonlabeled) FTOHs caused by the introduction of a mass-labeled surrogate can be controlled by blank subtracting or decreasing mass-labeled standard concentrations. Alternatively, different mass-labeled standards can also be used in sample analysis.

Per- and polyfluoroalkyl substances (PFAS) represent a large class of structurally diverse chemicals of increasing public concern, mostly due to their chemical stability and undetermined toxicity profiles. In laboratory animals, adverse effects implicated for certain PFAS, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in particular, include liver toxicity and the associated metabolic dysregulation, immune and thyroid alterations, reproductive toxicity, and selected tumors. The broad commercialization and environmental distribution of PFAS has drawn attention to the need for understanding risks associated with combined exposure to multiple PFAS in complex mixtures. The purpose of this investigation is to determine whether binary combinations of PFAS elicit a molecular response that is either greater than or less than the sum of the individual responses. Exposure of FaO rat hepatoma cells for 24 h to 25 μM-200 μM of the 4- and 8-carbon perfluorocarboxylic acids (PFBA and PFOA) or the 4, 6, and 8-carbon perfluorosulfonic acids (PFBS, PFHxS, and PFOS, respectively) individually caused a dose-dependent increase in PPARα-regulated expression of peroxisomal bifunctional enzyme (Ehhadh). Potency increased with carbon number, with the carboxylates eliciting a greater transcriptional response than the corresponding sulfonates. Combined exposure to PFOA and PFBA produced an effect that was significantly less than the sum of the individual responses. The response to the combination of PFOA and PFOS produced a summative effect at concentrations that were not cytotoxic. Combined exposures to PFOS and either PFBS or PFHxS at low noncytotoxic concentrations produced a transcriptional effect that was significantly less than the sum of the individual effects. The results demonstrate that among the five structurally related perfluoroalkyl acids included in this investigation, PPARα transcriptional activation in response to combined binary exposures is consistently at or below that predicted by the sum of the individual effects., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Due to numerous applications and excellent environmental stability, long-chain perfluorinated chemicals (PFCs) are ubiquitous in water across the world and adversely affect the living organisms. Thus, this study focused on the mitigation of the most frequently used long-chain PFCs namely perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) from water using reduced graphene oxide modified zinc ferrite immobilized chitosan beads (rGO-ZF@CB) as an adsorbent. The results from the adsorption isotherm and kinetic studies revealed that the adsorption data fitted well to the Langmuir and the pseudo-second-order models. According to the Langmuir isotherm, the rGO-ZF@CB possessed the maximum adsorption capacity of 16.07 mg/g for PFOA and 21.64 mg/g for PFOS. Both the electrostatic attractions and hydrophobic interactions have driven the removal of PFOA and PFOS by prepared rGO-ZF@CB. Eventually, the rGO-ZF@CB could be considered as an efficient adsorbent for the effective removal of PFOA and PFOS molecules from the aqueous environment., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Few articles are reported for the simultaneous separation and sensitive detection of the kynurenine pathway (KP) metabolites. This work describes a capillary electrochromatography-mass spectrometry (CEC-MS) method using acrylamido-2-methyl-1-propanesulfonic acid (AMPS) functionalized stationary phase. The AMPS column was prepared by first performing silanization of bare silica with gamma-maps, followed by polymerization with AMPS. The CEC-MS/MS methods were established for six upstream and three downstream KP metabolites. The simultaneous separation of all nine KP metabolites is achieved without derivatization for the first time in the open literature. Numerous parameters such as pH and the concentration of background electrolyte, the concentration of the polymerizable AMPS monomer, column length, field strength, and internal pressure were all tested to optimize the separation of multiple KP metabolites. A baseline separation of six upstream metabolites, namely tryptophan (TRP), kynurenine (KYN), 3-hydroxykynurenine (HKYN), kynurenic acid (KA), anthranilic acid (AA), and xanthurenic acid (XA), was possible at pH 9.25 within 26 min. Separation of six downstream and related metabolites, namely: tryptamine (TRPM), hydroxy‑tryptophan (HTRP), hydroxyindole-3 acetic acid (HIAA), 3-hydroxyanthranilic acid (3-HAA), picolinic acid (PA), and quinolinic acid (QA), was achieved at pH 9.75 in 30 min. However, the challenging simultaneous separation of all nine KP metabolites was only accomplished by increasing the column length and simultaneous application of internal pressure and voltage in 114 min. Quantitation of KP metabolites in commercial human plasma was carried out, and endogenous concentration of five KP metabolites was validated. The experimental limit of quantitation ranges from 100 to 10,000 nM (S/N = 8-832, respectively), whereas the experimental limit of detection ranges from 31 to 1000 nM (S/N = 2-16, respectively). Levels of five major KP metabolites, namely TRP, KYN, KA, AA, and QA, and their ratios in patient plasma samples previously screened for inflammatory biomarkers [C-reactive protein (CRP) and tumor necrosis factor-alpha (TNF-α)] was measured. Pairs of the level of metabolites with significant positive correlation were statistically evaluated., Competing Interests: Declaration of Competing Interest All authors of this manuscript declare that they have no known competing conflict of interests that may have influenced the research data reported in this paper., (Copyright © 2021. Published by Elsevier B.V.)

Purpose: Per- and poly-fluoroalkyl-substances (PFASs) are synthetic compounds that raised concern due to their potential adverse effects on human health. Long-chain PFAS were banned by government rules in many states, and thus, new emerging PFAS were recently introduced as substitutes. Among these, Perfluoro{acetic acid, 2-[(5-methoxy-1,3-dioxolan-4-yl)oxy]}, ammonium salt (C6O4) was recently introduced to produce a range of food contact articles and literature data about this compound are scanty. The aim of this study was to evaluate the in vitro effects of exposure to C6O4, compared with PFOA and PFOS on thyroid cells., Methods: FRTL5 rat-thyroid cell lines and normal human thyroid cells (NHT) were incubated with increasing concentrations of C6O4 for 24, 48, 72, and 144 h to assess cell viability by WST-1. Cell viability was confirmed by AnnexinV/PI staining. Long-chain PFAS (PFOA and PFOS) were used at same concentrations as positive controls. The proliferation of cells exposed to C6O4, PFOA, and PFOS was measured by staining with crystal violet and evaluation of optical density after incubation with SDS. Changes in ROS production by FRTL5 and NHT after exposure to C6O4 at short (10, 20, and 30 min) and long-time points (24 h) were evaluated by cytofluorimetry., Results: C6O4 exposure did not modify FRTL5 and NHT cell viability at any concentration and/or time points with no induction of necrosis/apoptosis. At difference, PFOS exposure reduced cell viability of FRTL5 while and NHT, while PFOA only in FRTL5. FRTL5 and NHT cell proliferation was reduced by incubation with by PFOA and PFOS, but not with C6O4. ROS production by NHT and FRTL5 cells was not modified after C6O4 exposure, at any time/concentration tested., Conclusions: The present in vitro study constitutes the first evaluation of the potential adverse effects of the new emerging PFAS C6O4 in cultured rat and human thyroid cells, suggesting its safety for thyroid cells in vitro., (© 2020. The Author(s).)

Lipases comprise one of the major enzyme classes in biotechnology with applications within, e.g., baking, brewing, biocatalysis, and the detergent industry. Understanding the mechanisms of lipase function and regulation is therefore important to facilitate the optimization of their function by protein engineering. Advances in single-molecule studies in model systems have provided deep mechanistic insights on lipase function, such as the existence of functional states, their dependence on regulatory cues, and their correlation to activity. However, it is unclear how these observations translate to enzyme behavior in applied settings. Here, single-molecule tracking of individual Thermomyces lanuginosus lipase (TLL) enzymes in a detergency application system allowed real-time direct observation of spatiotemporal localization, and thus diffusional behavior, of TLL enzymes on a lard substrate. Parallelized imaging of thousands of individual enzymes allowed us to observe directly the existence and quantify the abundance and interconversion kinetics between three diffusional states that we recently provided evidence to correlate with function. We observe redistribution of the enzyme's diffusional pattern at the lipid-water interface as well as variations in binding efficiency in response to surfactants and calcium, demonstrating that detergency effectors can drive the sampling of lipase functional states. Our single-molecule results combined with ensemble activity assays and enzyme surface binding efficiency readouts allowed us to deconvolute how application conditions can significantly alter protein functional dynamics and/or surface binding, both of which underpin enzyme performance. We anticipate that our results will inspire further efforts to decipher and integrate the dynamic nature of lipases, and other enzymes, in the design of new biotechnological solutions.

Allergic asthma, driven by T helper 2 cell-mediated immune responses to common environmental antigens, remains the most common respiratory disease in children. Perfluorinated chemicals (PFCs) are environmental contaminants of great concern, because of their wide application, persistence in the environment, and bioaccumulation. PFCs associate with immunological disorders including asthma and attenuate immune responses to vaccines. The influence of PFCs on the immunological response to allergens during childhood is unknown. We report here that a major PFC, perfluorooctane sulfonate (PFOS), inactivates house dust mite (HDM) to dampen 5-wk-old, early weaned mice from developing HDM-induced allergic asthma. PFOS further attenuates the asthma protective effect of the microbial product lipopolysaccharide (LPS). We demonstrate that PFOS prevents desensitization of lung epithelia by LPS, thus abolishing the latter's protective effect. A close mechanistic study reveals that PFOS specifically binds the major HDM allergen Der p1 with high affinity as well as the lipid A moiety of LPS, leading to the inactivation of both antigens. Moreover, PFOS at physiological human (nanomolar) concentrations inactivates Der p1 from HDM and LPS in vitro, although higher doses did not cause further inactivation because of possible formation of PFOS aggregates. This PFOS-induced neutralization of LPS has been further validated in primary human cell models and extended to an in vivo bacterial infection mouse model. This study demonstrates that early life exposure of mice to a PFC blunts airway antigen bioactivity to modulate pulmonary inflammatory responses, which may adversely affect early pulmonary health., Competing Interests: The authors declare no competing interest.

The aim of the present study is to determine four anionic alkyl sulfate (AS) surfactants with different alkyl chains, namely, C8, C10, C12, and C14, in wastewater by CE with capacitively coupled contactless conductivity detection (CE-C 4 D). The conditions effective for the separation of the four AS surfactants were systematically optimized and found to be in a Tris-His (50 mM/20 mM) BGE solution at a pH of 8.95, using a separation voltage of +15 kV, hydrodynamic injection by siphoning using a 20 cm injection height and an injection time of 20 s. The LODs for C8, C10, C12, and C14 were 2.58, 2.30, 2.08, and 3.16 mg/L, respectively. The conditions used to achieve the simultaneous adsorption and preconcentration of the AS surfactants using Al 2 O 3 beads were pH of 3 and 0.1 mM NaCl. The adsorption efficiencies were found to be 45.6, 50.8, 81.7, and 99.9%, while the desorption efficiencies reached 66.1, 70.4, 83.9, and 100.0% for C8, C10, C12, and C14, respectively. The concentrations of the AS surfactants in wastewater samples were quantified by CE-C 4 D after preconcentration by simultaneous adsorption using Al 2 O 3 beads. The results obtained from the proposed method were consistent with those obtained by HPLC-MS/MS, with a deviation of less than 15%. Our results indicate that the CE-C 4 D performed after preconcentration by an adsorption technique using Al 2 O 3 beads is a new, inexpensive, and suitable method for quantifying AS surfactants in wastewater samples., (© 2020 Wiley-VCH GmbH.)