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Journal Article 
Photooxidation of arsenite under 254 nm irradiation with a quantum yield higher than unity 
Ryu, J; Monllor-Satoca, D; Kim, D-H; Yeo, J; Choi, W 
In Press 
Environmental Science and Technology
ISSN: 0013-936X
EISSN: 1520-5851 
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. 
• Arsenic Hazard ID
          Considered New
          Considered New
     2. Lit Search Updates through Oct 2015
     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
• 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