Contribution of the photo-Fenton reaction to hydroxyl radical formation rates in river and rain water samples.
The hydroxyl radical (OH radical) formation rates from the photo-Fenton reaction in river and rain water samples were determined by using deferoxamine mesylate (DFOM), which makes a stable and strong complex with Fe(III), resulting in a suppression of the photo-Fenton reaction. The difference between the OH radical formation rates with and without added DFOM denotes the rate from the photo-Fenton reaction. The photoformation rates from the photo-Fenton reaction were in the range of 0.7 - 45.8 x 10(-12) and 2.7 - 32.3 x 10(-12) M s(-1) in river and rain water samples, respectively. A strong positive correlation between the OH radical formation rate from the photo-Fenton reaction and the amount of fluorescent matter in river water suggests that fluorescent matter, such as humic substances, plays an important role in the photo-Fenton reaction. In rain water, direct photolysis of hydrogen peroxide was an important source of OH radicals as well as the photo-Fenton reaction. The contributions of the photo-Fenton reaction to the OH radical photoformation rates in river and rain water samples were in the ranges of 2 - 29 and 5 - 38%, respectively. Taking into account the photo-Fenton reaction, 33 - 110 (mean: 80) and 42 - 110 (mean: 84)% of OH radical sources in river and rain water samples, respectively, collected in Hiroshima prefecture were elucidated.
Nakatani
Nobutake
N
Graduate School for International Development and Cooperation, Hiroshima University, Higashi-Hirosima, Japan. nnakatan@hiroshima-u.ac.jp
Ueda
Marina
M
Shindo
Hirotaka
H
Takeda
Kazuhiko
K
Sakugawa
Hiroshi
H
D003676:Deferoxamine / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D010777:Photochemistry; D011891:Rain / Q000737:chemistry*; D045483:Rivers / Q000737:chemistry*
C045076:Fenton's reagent; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D007501:Iron; D003676:Deferoxamine