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Homogeneous photoconversion of seawater uranium using copper and iron mixed-oxide semiconductor electrodes

Title
Homogeneous photoconversion of seawater uranium using copper and iron mixed-oxide semiconductor electrodes
Authors
Lee, S.[Lee, Seung Hoon]Kang, U.[Kang, Un Seock]Piao, G.[Piao, Guangxia]Kim, S.[Kim, Soon Hyun]Han, D.S.[Han, Dong Suk]Park, H.[Park, Hyun Woong]
DGIST Authors
Kim, S.[Kim, Soon Hyun]
Issue Date
2017
Citation
Applied Catalysis B: Environmental, 207, 35-41
Type
Article
Article Type
Article
Keywords
Electron ShuttleNuclear WasteP-TypePhotoelectrochemicalResource Recovery
ISSN
0926-3373
Abstract
Sunlight-driven conversion of hexavalent uranium (U(VI)) in seawater is achieved with mixed p-type CuO and CuFeO2 (CuO/CuFeO2) photocatalyst film electrodes synthesized via electrodeposition (ED) of Cu(II) and Fe(III), followed by annealing in air. The mixed photocatalysts exhibit a double-layer configuration with crystalline structures of CuO and CuFeO2. On irradiation of the CuO/CuFeO2 electrodes (held at −0.5 V vs. SCE) with solar simulated light (air mass 1.5; 100 mW cm−2), the U(VI) concentration decreases with time, while the total amount of uranium in solution does not change. This indicates that virtually all conversion reactions of U(VI) occur in the bulk solution, while surface reactions are limited due to insignificant adsorption of U(VI). U(VI) conversion leads to the mixed production of lower oxidation states U4+, U14/3+, and U16/3+ at a ratio of 42:28:30, with an overall Faradaic efficiency of ∼98%. The kinetics and induction time for U(VI) conversion are significantly influenced by the conditions of photocatalyst synthesis (CuO/CuFeO2, CuO, and CuFeO2; ED times of 2–4 h), the applied potential value (−0.4, −0.5, and −0.6 V vs. SCE), and the seawater condition (air-equilibrated vs. N2-purged; pH 3–10.4). Based on the obtained results, O2 is proposed to play a key role in shuttling photogenerated electrons between the electrodes and U(VI). In addition, the existence of an induction time is discussed in terms of material and reaction pathway. © 2017 Elsevier B.V.
URI
http://hdl.handle.net/20.500.11750/2086
DOI
10.1016/j.apcatb.2017.02.004
Publisher
Elsevier B.V.
Related Researcher
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Collection:
Smart Textile Convergence Research Group1. Journal Articles


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