Authors
Peijie Li, Jinchuan Lian, Xiaoxiang Cheng, Xinsheng Luo, Kunyu Chen, Congwei Luo, Ruimin Mu, Daoji Wu, Tao Yang
Published in
Water research. Volume 308. Issue Pt B. Pages 126889. Sep 07, 2026. Epub Sep 07, 2026.
Abstract
Although light-assisted ferrate (Fe(VI)) activation offers an activator-free strategy for micropollutant abatement, how visible light generates Fe(V)/Fe(IV) remains unclear at the molecular level. Here, five narrow-band LEDs (440-525 nm) were used to link Fe(VI) photochemistry with pollutant oxidation kinetics and iron-species contributions. At 440 nm, Vis-LED/Fe(VI) degraded 79.6-99.3% of six electron-rich micropollutants within 3 min, increasing rate constants by up to 4.3-fold relative to Fe(VI). Scavenging experiments and kinetic modeling identified Fe(V) and Fe(IV) as the dominant reactive species, together accounting for over 96% of diclofenac sodium (DCF) degradation. Time-dependent density functional theory calculations showed that visible excitation induced ligand-to-metal charge transfer (LMCT), which elongated a Fe-O bond from 1.654 to 2.025 Å and generated an Fe(V)-oxyl excited state that abstracted a hydrogen atom from water to give Fe(V). The apparent quantum yield of Fe(VI) decomposition decreased from 0.140 to 0.104 mol einstein-1 as wavelength increased from 440 to 525 nm, consistent with the charge-transfer component being photochemically productive. The system performance improved with light intensities and Fe(VI) concentrations, but declined under alkaline conditions and in humic-acid-rich water. These results establish visible-light activation of Fe(VI) via LMCT and identify Fe(V)/Fe(IV) as the oxidants responsible for micropollutant abatement.
PMID:
42731487
Bibliographic data and abstract were imported from PubMed on 13 Sep 2026.
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