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HERO ID
1797795
Reference Type
Journal Article
Title
Photooxidation of arsenite under 254 nm irradiation with a quantum yield higher than unity
Author(s)
Ryu, J; Monllor-Satoca, D; Kim, D-H; Yeo, J; Choi, W
Year
2013
Is Peer Reviewed?
1
Journal
Environmental Science & Technology
ISSN:
0013-936X
EISSN:
1520-5851
Volume
47
Issue
16
Page Numbers
9381-9387
Language
English
PMID
23879475
DOI
10.1021/es402011g
Web of Science Id
WOS:000323471700048
Abstract
Arsenite (As(III)) in water was demonstrated to be efficiently oxidized to arsenate (As(V)) under 254 nm UV irradiation without needing any chemical reagents. Although the molar absorption coefficient of As(III) at 254 nm is very low (2.49±0.1 M(-1)cm(-1)), the photooxidation proceeded with a quantum yield over 1.0, which implies a chain of propagating oxidation cycles. The rate of As(III) photooxidation was highly enhanced in the presence of dissolved oxygen, which can be ascribed to its dual role as an electron acceptor of photo-excited As(III) and a precursor of oxidizing radicals. The in-situ production of H2O2 was observed during the photooxidation of As(III) and its subsequent photolysis under UV irradiation produced OH radicals. The addition of tert-butyl alcohol as OH radical scavengers significantly reduced (but not completely inhibited) the oxidation rate, which indicates that OH radicals as well as superoxide serve as an oxidant of As(III). Superoxide, H2O2, and OH radicals were all in situ generated from the irradiated solution of As(III) in the presence of dissolved O2 and their subsequent reactions with As(III) induce the regeneration of some oxidants, which makes the overall quantum yield higher than 1. The homogeneous photolysis of arsenite under 254 nm irradiation can be also proposed as a new method of generating OH radicals.
Tags
IRIS
•
Arsenic Hazard ID
PubMed
Considered New
PubMed
Considered New
2. Lit Search Updates through Oct 2015
PubMed
Considered
7. Other Studies through Oct 2015
Physical Chemistry/Engineering
•
Arsenic (Inorganic)
1. Literature
Lit search updates through Oct 2015
3. Hazard ID Screening
Other potentially supporting studies
•
n-Butanol
Database searches
Pubmed
•
tert-Butanol
Considered Studies
Electronic Search
•
n-Butanol
Database Searches - March 2014 (private)
Pubmed - 3/2014
Excluded (not pertinent)
Not chemical specific
•
tert-Butanol
Excluded/ Not on Topic
Methodology/Solvent
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