Details
| Original language | English |
|---|---|
| Pages (from-to) | 218-226 |
| Number of pages | 9 |
| Journal | Applied Catalysis B: Environmental |
| Volume | 242 |
| Early online date | 22 Sept 2018 |
| Publication status | Published - Mar 2019 |
Abstract
Hematite nanoparticles (nHm) were tested for Cr(VI) photocatalytic reduction (300 μM) in the presence of different electron donors such as citrate (Cit), oxalate (Ox), 2-propanol and methanol. At pH 3 and under irradiation at λ ≥ 310 nm, almost negligible reaction took place in the absence of donor or with the alcohols, while the reduction was very rapid in the presence of Cit (less than 25 min), and faster with Ox (15 min). Homogeneous experiments with FeCl 3 instead of nHm showed a complete Cr(VI) reduction in the presence of both complexing agents in less than 10 min. Under irradiation at λ > 495 nm and with nHm at pH 3, a good Cr(VI) transformation took place with both donors, but at a considerably lower rate than under UV light (around 100% at 180 min), the decay being negligible in the homogeneous systems with Fe(III). Under irradiation at λ > 610 nm, no Cr(VI) transformation took place over nHm. Experiments at pH 6 under UV–Vis light with Cit in the presence of nHm gave a good Cr(VI) decay, faster with Fe(III) (60% and 90% in 105 min, respectively); some Cr(VI) transformation (around 35% in 180 min) was found with Cit under Vis light. Interestingly, at both wavelength ranges, the reaction was negligible when Ox was used. Mechanisms taking place under the different conditions were proposed, including the role of surface charge transfer complexes on nHm.
Keywords
- Citrate, Cr(VI), Nanohematite, Oxalate, Photocatalysis
ASJC Scopus subject areas
- Chemical Engineering(all)
- Catalysis
- Environmental Science(all)
- Chemical Engineering(all)
- Process Chemistry and Technology
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In: Applied Catalysis B: Environmental, Vol. 242, 03.2019, p. 218-226.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Photocatalytic reduction of Cr(VI) on hematite nanoparticles in the presence of oxalate and citrate
AU - Kretschmer, Imme
AU - Senn, Alejandro M.
AU - Meichtry, J. Martín
AU - Custo, Graciela
AU - Halac, Emilia B.
AU - Dillert, Ralf
AU - Bahnemann, Detlef
AU - Litter, Marta I.
N1 - Funding information: This work was partially supported by Agencia Nacional de Promoción Científica y Tecnológica of Argentina , PICT-0463 and PICT-208 grants and by the Scientific and Technological Cooperation Argentina-Germany BMBF/MINCYT ARG 07/005 .
PY - 2019/3
Y1 - 2019/3
N2 - Hematite nanoparticles (nHm) were tested for Cr(VI) photocatalytic reduction (300 μM) in the presence of different electron donors such as citrate (Cit), oxalate (Ox), 2-propanol and methanol. At pH 3 and under irradiation at λ ≥ 310 nm, almost negligible reaction took place in the absence of donor or with the alcohols, while the reduction was very rapid in the presence of Cit (less than 25 min), and faster with Ox (15 min). Homogeneous experiments with FeCl 3 instead of nHm showed a complete Cr(VI) reduction in the presence of both complexing agents in less than 10 min. Under irradiation at λ > 495 nm and with nHm at pH 3, a good Cr(VI) transformation took place with both donors, but at a considerably lower rate than under UV light (around 100% at 180 min), the decay being negligible in the homogeneous systems with Fe(III). Under irradiation at λ > 610 nm, no Cr(VI) transformation took place over nHm. Experiments at pH 6 under UV–Vis light with Cit in the presence of nHm gave a good Cr(VI) decay, faster with Fe(III) (60% and 90% in 105 min, respectively); some Cr(VI) transformation (around 35% in 180 min) was found with Cit under Vis light. Interestingly, at both wavelength ranges, the reaction was negligible when Ox was used. Mechanisms taking place under the different conditions were proposed, including the role of surface charge transfer complexes on nHm.
AB - Hematite nanoparticles (nHm) were tested for Cr(VI) photocatalytic reduction (300 μM) in the presence of different electron donors such as citrate (Cit), oxalate (Ox), 2-propanol and methanol. At pH 3 and under irradiation at λ ≥ 310 nm, almost negligible reaction took place in the absence of donor or with the alcohols, while the reduction was very rapid in the presence of Cit (less than 25 min), and faster with Ox (15 min). Homogeneous experiments with FeCl 3 instead of nHm showed a complete Cr(VI) reduction in the presence of both complexing agents in less than 10 min. Under irradiation at λ > 495 nm and with nHm at pH 3, a good Cr(VI) transformation took place with both donors, but at a considerably lower rate than under UV light (around 100% at 180 min), the decay being negligible in the homogeneous systems with Fe(III). Under irradiation at λ > 610 nm, no Cr(VI) transformation took place over nHm. Experiments at pH 6 under UV–Vis light with Cit in the presence of nHm gave a good Cr(VI) decay, faster with Fe(III) (60% and 90% in 105 min, respectively); some Cr(VI) transformation (around 35% in 180 min) was found with Cit under Vis light. Interestingly, at both wavelength ranges, the reaction was negligible when Ox was used. Mechanisms taking place under the different conditions were proposed, including the role of surface charge transfer complexes on nHm.
KW - Citrate
KW - Cr(VI)
KW - Nanohematite
KW - Oxalate
KW - Photocatalysis
UR - http://www.scopus.com/inward/record.url?scp=85054460575&partnerID=8YFLogxK
U2 - 10.1016/j.apcatb.2018.09.059
DO - 10.1016/j.apcatb.2018.09.059
M3 - Article
VL - 242
SP - 218
EP - 226
JO - Applied Catalysis B: Environmental
JF - Applied Catalysis B: Environmental
SN - 0926-3373
ER -