Efficient photo-assisted reduction of Cr(VI) via activated carbon mediated Z-scheme FeS2/α-FeOOH/C heterojunction: Focusing on molecular oxygen fate and synergetic reduction mechanism
Herein, pyrite (FeS2), goethite (α-FeOOH) and activated carbon (C) were combined to construct FeS2/α-FeOOH/C composites with C mediated Z-scheme heterojunction for efficient photo-assisted Cr(VI) reduction. Characterization tests indicated the strong interaction via Fe-O-C and C-S-C, the increased a...
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Veröffentlicht in: | Journal of water process engineering 2025-01, Vol.69, p.106661, Article 106661 |
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Sprache: | eng |
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Zusammenfassung: | Herein, pyrite (FeS2), goethite (α-FeOOH) and activated carbon (C) were combined to construct FeS2/α-FeOOH/C composites with C mediated Z-scheme heterojunction for efficient photo-assisted Cr(VI) reduction. Characterization tests indicated the strong interaction via Fe-O-C and C-S-C, the increased amount of crystal defects and surface oxygenic functional groups, and the decreased agglomeration degree during combination strengthened electron transport and visible light conversion efficiency, resulting in synergistic effect for enhanced Cr(VI) removal. Additionally, C mediated Z-scheme heterojunction with lower resistance facilitated the transfer and separation efficiency of photo-generated carriers, further accelerating Cr(VI) reduction. Consequently, almost 100 % of Cr(VI) was reduced via FeS2/α-FeOOH/C in 60 min, 4 times that of pristine FeS2. Quenching, EPR and control experiments confirmed photocatalysis made more contribution than single reductive reagents (FeS2) in Cr(VI) reduction. The specific contribution rate of reductive species like e−, Fe2+, S22− and •O2− in this complicated system was firstly detailedly demonstrated and •O2− played a predominant role under oxic condition. Meanwhile, oxidative species like H2O2, 1O2 and •OH ascribed to DO activation or photo-generated h+ preferred to reacted with Fe2+ and S22− with higher reducibility and-only delayed Cr(VI) reduction rate. Hence, the final total Cr(VI) removal efficiency and generated Cr(III) kept stable in oxic solution.
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•C mediated Z-scheme heterojunction was successfully constructed in FeS2/α-FeOOH/C.•Strong interaction and combination enhanced electron transport capacity.•Contribution rate of reductive species for Cr(VI) reduction was detailly described.•Oxidative species reacted with Fe2+ and S22− only inhibited Cr(VI) reduction rate. |
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ISSN: | 2214-7144 2214-7144 |
DOI: | 10.1016/j.jwpe.2024.106661 |