Regeneration of exhausted adsorbents after PFAS adsorption: a critical review

Journal of Hazardous Materials, Journal Year: 2024, Volume and Issue: 471, P. 134429 - 134429

Published: April 27, 2024

Language: Английский

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Selective perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) adsorption by nanoscale zero-valent iron (nZVI): performance and mechanisms

Environmental Science Nano, Journal Year: 2024, Volume and Issue: 11(5), P. 1915 - 1925

Published: Jan. 1, 2024

This study investigated the adsorption of PFOA and PFOS by nanoscale zero-valent iron, revealing mechanism enriching understanding environmental remediation.

Language: Английский

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Modified competitive Langmuir model for prediction of multispecies PFAS competitive adsorption equilibria on colloidal activated carbon

Separation and Purification Technology, Journal Year: 2024, Volume and Issue: 345, P. 127368 - 127368

Published: April 4, 2024

Competitive adsorption of four perfluoroalkyl substances (PFAS), i.e., perfluorobutyl sulfonate (PFBS), perfluorohexane (PFHxS), perfluorooctanoate (PFOA), and perfluorooctane (PFOS), on colloidal activated carbon (CAC) was studied a new predictive model, modified competitive Langmuir model (MCLM), proposed to predict the equilibria. The is modification (CLM) that gives additional weighting molecular weight PFAS molecules. A comparative study done test capability by comparing its predictions widely used CLM ideal adsorbed solution theory (IAST), as well experimental data from batch experiments seven different mixtures abovementioned PFAS. models were tested various combinations two three analytes. analysis showed better MCLM over existing in most cases. Additionally, an error performed fit single-solute isotherms indicated isotherm Freundlich isotherm. Moreover, also approximately equal impact PFOA PFHxS PFOS higher PFHxS, compared PFOA, PFBS which hints at hydrophobicity but due smaller size pore accessibility.

Language: Английский

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Ecological risk of per- and polyfluorinated alkyl substances in the phytoremediation process: a case study for ecologically keystone species across two generations

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 951, P. 174962 - 174962

Published: July 26, 2024

Language: Английский

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Impacts of Perfluoroalkyl Substances on Aqueous and Nonaqueous Phase Liquid Dechlorination by Sulfidized Nanoscale Zerovalent Iron

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(25), P. 11193 - 11202

Published: June 11, 2024

Per- and poly fluoroalkyl substances (PFASs) are often encountered with nonaqueous phase liquid (NAPL) in the groundwater at fire-fighting military training sites. However, it is unclear how PFASs affect dechlorination performance of sulfidized nanoscale zerovalent iron (S-nFe0), which an emerging promising NAPL remediation agent. Here, S-nFe0 synthesized controllable S speciation (FeS or FeS2) were characterized to assess their interactions for trichloroethylene (TCE-NAPL). Surface-adsorbed blocked materials' reactive sites inhibited aqueous TCE dechlorination. In contrast, PFASs-adsorbed particles improved hydrophobicity tended enrich NAPL–water interface, re-exposed after accumulation into accelerate This PFASs-induced phenomenon allowed materials present a higher reactivity (up 1.8-fold) high electron efficiency 99%) TCE-NAPL Moreover, nFe0-FeS2 was more readily enriched interface selective than nFe0-FeS, regardless coexisting PFASs. These results unveil that small amount yet previously overlooked can favor reductions by S-nFe0, highlighting importance transportation induced remediation.

Language: Английский

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Groundwater solutes influence the adsorption of short-chain perfluoroalkyl acids (PFAA) to colloidal activated carbon and impact performance for in situ groundwater remediation

Journal of Hazardous Materials, Journal Year: 2024, Volume and Issue: 474, P. 134746 - 134746

Published: May 27, 2024

Subsurface injection of colloidal activated carbon (CAC) is an in situ remediation strategy for perfluoroalkyl acids (PFAA), but the influence groundwater solutes on longevity uncertain, particularly short-chain PFAA. We quantify impact inorganic anions, dissolved organic matter (DOM), and stabilizing polymer PFAA adsorption to a commercial CAC. Surface characterization supported chain-length dependent results mechanisms are provided. Inorganic anions decreased (<7 perfluorinated carbons) due competitive effects, while long-chain (≥ 7 were less impacted. DOM all manner. High concentrations (10 mg/L, ∼5 mg OC/L) PFOA by factor 2, PFPeA one order magnitude, completely hindered PFBA adsorption. MW has than low DOM, possibly differences ability access CAC micropores. Low (1 ∼0.5 did not CMC (90 kDa average MW) had negligible likely minimal surface coverage. Longevity modeling demonstrated that limit capacity barrier,

Language: Английский

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Removal of PFAS by hydrotalcite: Adsorption mechanisms, effect of adsorbent aging, and thermal regeneration

Water Research, Journal Year: 2024, Volume and Issue: 260, P. 121925 - 121925

Published: June 11, 2024

Layered double hydroxides (LDH) have been shown to be effective adsorbents, but their utility for the treatment of per- and polyfluoroalkyl substances (PFAS) in water has not fully explored. In this study, adsorption 9 PFAS on hydrotalcite (HT), a type LDH, was investigated using reaction solutions with environmentally relevant concentrations. The individual by HT depended upon range factors, including temperature used pre-treat (i.e., calcine) HT, aging conditions, presence anions solution. calcined near 400 °C most effectively adsorbed PFAS, its ability adsorb sensitive storage conditions. CO2 moisture from air, which likely resulted re-intercalation CO32− into interlayer regions observed reduce may explain performance loss over time. trend among influence process Cl−, NO3−, SO42−, indicated that occurred via combination ion exchange, electrostatic attraction, hydrophobic interactions, although relative importance each mechanism deserves further investigation. During we also demonstrated first time can thermally regenerated at without affecting PFOS PFBA. Overall, our results suggest serve as an alternative treatment.

Language: Английский

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Effects of Physical and Chemical Aging of Colloidal Activated Carbon on the Adsorption of Per- and Polyfluoroalkyl Substances

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

Published: Feb. 14, 2025

Colloidal activated carbon (CAC) is an injectable adsorbent that sequesters per- and polyfluoroalkyl substances (PFAS) in the subsurface, serving as situ remediation technology for PFAS-impacted sites. However, effectiveness of CAC sorptive barrier could change over time due to alterations its physicochemical properties induced by aging processes. In this study, effects on surface resulting impact adsorption behaviors PFAS compounds were determined using four accelerated treatments, including wet-dry cycling (W/D), hydrogen peroxide (H), Fenton's reagent (F), mineral acid (A). treatments showed a greater physical structure chemical composition than either W/D-CAC H-CAC. Aging lowered specific area anion exchange capacity, increased oxygen content, point zero charge, suggesting negative impacts capacity removal. This reduction sorption was confirmed batch isotherm experiments. All aged had lower multisolute system, six with different chain lengths (C4-C8) functional groups (sulfonate or carboxylate), only exception being perfluorooctanesulfonic (PFOS). The results suggest process important, yet often overlooked, factor determining long-term removal, especially shorter-chain hydrophilic PFAS. More research needed verify influence field-scale processes performance longevity.

Language: Английский

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Influences of dissolved organic matters on the adsorption and bioavailability of sulfadiazine: Molecular weight- and type-dependent heterogeneities

Chemosphere, Journal Year: 2024, Volume and Issue: 354, P. 141677 - 141677

Published: March 9, 2024

Language: Английский

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Performance of pitcher-type POU filters for the removal of 75 PFAS from drinking water: comparing different water sources

Frontiers in Environmental Chemistry, Journal Year: 2024, Volume and Issue: 5

Published: June 4, 2024

This study presents a comprehensive assessment of the performance popular pitcher-type point-of-use (POU) water filters to remove PFAS contaminants from tap waters. The evaluated filters, Brita (Elite and Standard), ZeroWater, Aquagear, ClearlyFiltered, were tested for their efficacy in removing 75 targeted PFAS, total organic carbon (TOC), dissolved solids (TDS), chloride, sulfate two Canadian waters with background Σ concentrations 13 56 ng/L. Overall, performances varied depending on structure filter media, source, specific present. ZeroWater was top performer case removal. volume-weighted average removal after 160 L filtration using Saint-Donat 99% 77% 20% (Elite). In Montreal water, which had different characteristics lower levels, ≈100% 96% 60% 48% (Elite), 38% (Standard). Both laboratory home tests involving yielded similar high-performance results water. Although exhibited high (99%) TDS TOC desorption significant drop pH observed 80 L, phenomenon explained by higher concentration anions this contrast, no due anions. Aquagear demonstrated an unusual increase initial 20 needs further evaluation. discusses individual performance, influence characteristics, potential meet new NSF guidelines, provides valuable insights consumers seeking choose appropriate easy-to-use system ensure safe clean drinking regions.

Language: Английский

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