Dechlorination Helps Defluorination: Insights into the Defluorination Mechanism of Florfenicol by S-nZVI and DFT Calculations on the Reaction Pathways

Environmental Science & Technology, Год журнала: 2024, Номер 58(5), С. 2542 - 2553

Опубликована: Янв. 23, 2024

Defluorination is essential to eliminate the antibiotic resistance and detrimental effects of florfenicol (C12H14Cl2FNO4S, FF), which achievable by sulfidated nanoscale zerovalent iron (S-nZVI), yet a comprehensive understanding mechanism lacking. Herein, we used experimental data density functional theory calculations demonstrate four dechlorination-promoted defluorination pathways FF, depending on S-nZVI or not. FF was defluorinated in rapid then slow but continuous manner, accompanying consecutive dechlorination deschloro (dFF) dideschloro (ddFF). Unexpectedly, predominant occurs spontaneous hydrolysis ddFF form hydrolyzed byproduct (HO-ddFF), i.e., independent S-nZVI, initiated intramolecular attack from carbonyl O alkyl F thus limited for dFF owing diminished nucleophilicity electron-withdrawing Cl. The removal Cl also makes reductive amenable. other two minor more occur synergy with dFF, are mediated reactive carbanion intermediates generate HO-dFF HO-ddFF, respectively. reliability these dechlorination-facilitated verified consistency theoretical data, providing valuable insights into degradation fluorinated contaminants.

Язык: Английский

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Lattice-sulfur-impregnated zero-valent iron crystals for long-term metal encapsulation

Nature Sustainability, Год журнала: 2024, Номер 7(10), С. 1264 - 1272

Опубликована: Авг. 7, 2024

Язык: Английский

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

Environmental Science & Technology, Год журнала: 2024, Номер 58(25), С. 11193 - 11202

Опубликована: Июнь 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.

Язык: Английский

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Mechanochemical nitridation of micron zero-valent iron for enhanced dechlorination of trichloroethylene: Mechanistic insights into nitrogen sources and ball milling conditions

Separation and Purification Technology, Год журнала: 2024, Номер 337, С. 126381 - 126381

Опубликована: Янв. 14, 2024

Язык: Английский

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New insights into long-lasting Cr(VI) removal from groundwater using in situ biosulfidated zero-valent iron with sulfate-reducing bacteria

Journal of Environmental Management, Год журнала: 2024, Номер 355, С. 120488 - 120488

Опубликована: Март 1, 2024

Язык: Английский

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