Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 3973-3981 |
| Seitenumfang | 9 |
| Fachzeitschrift | Environmental Science and Technology |
| Jahrgang | 51 |
| Ausgabenummer | 7 |
| Publikationsstatus | Veröffentlicht - 4 Apr. 2017 |
Abstract
We investigated a sequential photocatalysis-dark reaction, wherein organic pollutants were degraded on Ag/TiO 2 under UV irradiation and the dark reduction of hexavalent chromium (Cr(VI)) was subsequently followed. The photocatalytic oxidation of 4-chlorophenol (4-CP), a test organic substrate, induced the generation of degradation intermediates and the storage of electrons in Ag/TiO 2 which were then utilized for reducing Cr(VI) in the postirradiation period. The dark reduction efficiency of Cr(VI) was much higher with Ag/TiO 2 (87%), compared with bare TiO 2 (27%) and Pt/TiO 2 (22%). The Cr(VI) removal by Ag/TiO 2 (87%) was contributed by adsorption (31%), chemical reduction by intermediates of 4-CP degradation (26%), and reduction by electrons stored in Ag (30%). When formic acid, humic acid or ethanol was used as an alternative organic substrate, the electron storage effect was also observed. The postirradiation removal of Cr(VI) on Ag/TiO 2 continued for hours, which is consistent with the observation that a residual potential persisted on the Ag/TiO 2 electrode in the dark whereas little residual potential was observed on bare TiO 2 and Pt/TiO 2 electrodes. The stored electrons in Ag/TiO 2 and their transfer to Cr(VI) were also indicated by the UV-visible absorption spectral change. Moreover, the electrons stored in the preirradiated Ag/TiO 2 reacted with O 2 with showing a sign of low-level OH radical generation in the dark period.
ASJC Scopus Sachgebiete
- Chemie (insg.)
- Allgemeine Chemie
- Umweltwissenschaften (insg.)
- Umweltchemie
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in: Environmental Science and Technology, Jahrgang 51, Nr. 7, 04.04.2017, S. 3973-3981.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Sequential Process Combination of Photocatalytic Oxidation and Dark Reduction for the Removal of Organic Pollutants and Cr(VI) using Ag/TiO2
AU - Choi, Y.
AU - Koo, M.S.
AU - Bokare, A.D.
AU - Kim, D.-H.
AU - Bahnemann, D.W.
AU - Choi, W.
N1 - Funding information: This work was supported by Global Research Laboratory (GRL) Program (NRF-2014K1A1A2041044) and KCAP (Sogang Univ.) (2009-0093880), which were funded by the Korea Government (MSIP) through the National Research Foundation (NRF).
PY - 2017/4/4
Y1 - 2017/4/4
N2 - We investigated a sequential photocatalysis-dark reaction, wherein organic pollutants were degraded on Ag/TiO 2 under UV irradiation and the dark reduction of hexavalent chromium (Cr(VI)) was subsequently followed. The photocatalytic oxidation of 4-chlorophenol (4-CP), a test organic substrate, induced the generation of degradation intermediates and the storage of electrons in Ag/TiO 2 which were then utilized for reducing Cr(VI) in the postirradiation period. The dark reduction efficiency of Cr(VI) was much higher with Ag/TiO 2 (87%), compared with bare TiO 2 (27%) and Pt/TiO 2 (22%). The Cr(VI) removal by Ag/TiO 2 (87%) was contributed by adsorption (31%), chemical reduction by intermediates of 4-CP degradation (26%), and reduction by electrons stored in Ag (30%). When formic acid, humic acid or ethanol was used as an alternative organic substrate, the electron storage effect was also observed. The postirradiation removal of Cr(VI) on Ag/TiO 2 continued for hours, which is consistent with the observation that a residual potential persisted on the Ag/TiO 2 electrode in the dark whereas little residual potential was observed on bare TiO 2 and Pt/TiO 2 electrodes. The stored electrons in Ag/TiO 2 and their transfer to Cr(VI) were also indicated by the UV-visible absorption spectral change. Moreover, the electrons stored in the preirradiated Ag/TiO 2 reacted with O 2 with showing a sign of low-level OH radical generation in the dark period.
AB - We investigated a sequential photocatalysis-dark reaction, wherein organic pollutants were degraded on Ag/TiO 2 under UV irradiation and the dark reduction of hexavalent chromium (Cr(VI)) was subsequently followed. The photocatalytic oxidation of 4-chlorophenol (4-CP), a test organic substrate, induced the generation of degradation intermediates and the storage of electrons in Ag/TiO 2 which were then utilized for reducing Cr(VI) in the postirradiation period. The dark reduction efficiency of Cr(VI) was much higher with Ag/TiO 2 (87%), compared with bare TiO 2 (27%) and Pt/TiO 2 (22%). The Cr(VI) removal by Ag/TiO 2 (87%) was contributed by adsorption (31%), chemical reduction by intermediates of 4-CP degradation (26%), and reduction by electrons stored in Ag (30%). When formic acid, humic acid or ethanol was used as an alternative organic substrate, the electron storage effect was also observed. The postirradiation removal of Cr(VI) on Ag/TiO 2 continued for hours, which is consistent with the observation that a residual potential persisted on the Ag/TiO 2 electrode in the dark whereas little residual potential was observed on bare TiO 2 and Pt/TiO 2 electrodes. The stored electrons in Ag/TiO 2 and their transfer to Cr(VI) were also indicated by the UV-visible absorption spectral change. Moreover, the electrons stored in the preirradiated Ag/TiO 2 reacted with O 2 with showing a sign of low-level OH radical generation in the dark period.
UR - http://www.scopus.com/inward/record.url?scp=85020025015&partnerID=8YFLogxK
U2 - 10.1021/acs.est.6b06303
DO - 10.1021/acs.est.6b06303
M3 - Article
VL - 51
SP - 3973
EP - 3981
JO - Environmental Science and Technology
JF - Environmental Science and Technology
SN - 0013-936X
IS - 7
ER -