Visible-light photocatalytic O2-to-H2O2 via nitrogen-graphene quantum dots-modified Bi2Fe4O9 for synchronizing the reduction of Cr(VI) and oxidation of organic contaminants: Kinetics, mechanism, and performance

[Display omitted] •N-GQDs/Bi2Fe4O9 suppress charge recombination and electron accumulation.•N-GQDs/Bi2Fe4O9 enhances in-situ H2O2 generation and H2O2 activation.•Electrons accumulation around N-GQDs accelerate the redox cycles of Fe(II)/Fe(III).•N-GQDs/Bi2Fe4O9 achieves simultaneous toxic Cr(VI) red...

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Veröffentlicht in:Chemical engineering journal (Lausanne, Switzerland : 1996) Jg. 487; S. 150712
Hauptverfasser: Wei, Ling-Wei, Zheng, Meng-Wei, Liu, Shou-Heng, Paul Wang, Hong, Pu, Ying-Chih, Nguyen, Van-Can
Format: Journal Article
Sprache:Englisch
Veröffentlicht: Elsevier B.V 01.05.2024
Schlagworte:
chromium
Cr(VI) reduction
irradiation
light
Organic contaminant oxidation
oxidation
Photo-Fenton process
photocatalysis
photocatalysts
Reactive oxygen species
Redox cycle
solar energy
species
toxicity
wastewater
Reactive oxygen species
Photo-Fenton process
Redox cycle
Cr(VI) reduction
Organic contaminant oxidation
ISSN:1385-8947, 1873-3212
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Zusammenfassung:[Display omitted] •N-GQDs/Bi2Fe4O9 suppress charge recombination and electron accumulation.•N-GQDs/Bi2Fe4O9 enhances in-situ H2O2 generation and H2O2 activation.•Electrons accumulation around N-GQDs accelerate the redox cycles of Fe(II)/Fe(III).•N-GQDs/Bi2Fe4O9 achieves simultaneous toxic Cr(VI) reduction and BPA oxidation in wastewater.•N-GQDs/Bi2Fe4O9 enables energy self-sufficient and simplified wastewater treatment methods. Synergistic coexistence of toxic chromium and organic contaminants in wastewater has made treatments highly complicated. As solar-driven wastewater treatments become increasingly environmentally and economically attractive, a photocatalyst (denoted as N-GQDs/Bi2Fe4O9) is developed for photocatalytic reduction of Cr(VI) and simultaneous oxidation of organic contaminants in wastewater. Incorporating N-GQDs (as electron reservoir) into Bi2Fe4O9 modulates the band structure (from 2.40 to 2.24 eV), facilitating charge transfer and electron accumulation at N-GQDs. Due to the photo-Fenton synergistic reaction between N-GQDs/Bi2Fe4O9 photocatalysis process, N-GQDs/ Bi2Fe4O9 demonstrates excellent H2O2 generation (1.64 μM min−1) and H2O2 activation (0.0063 min−1) performance, leading to generation of more highly reactive species (i.e., OH radicals), achieving BPA removal of 99.9 % under visible-light irradiation for 100 min. Interestingly, the photo-Fenton synergistic reaction enhances the reduction of Cr(VI) (99.8 %), while the Fe(II) active sites on the N-GQDs/Bi2Fe4O9 can also promote the synchronized Cr(VI) reduction. Also, the accumulated electron around N-GQDs enhances redox cycles of Fe(II)/Fe(III) reactions to realize the sustainable photo-Fenton catalytic reaction. This new N-GQDs/Bi2Fe4O9 photocatalyst demonstrates the feasibility of concurrent reduction of toxic Cr(VI)-to-Cr(III) and oxidation of organic contaminants in wastewater with a simple process via nearly unlimited solar energy.
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ISSN:1385-8947
1873-3212
DOI:10.1016/j.cej.2024.150712