Hydroxyl radical generation with a high power ultraviolet light emitting diode (UV-LED) and application for determination of hydroxyl radical reaction rate constants

作者：Takeda Kazuhiko^*; Fujisawa Katsunari; Nojima Hitoshi; Kato Ryota; Ueki Ryuta; Sakugawa Hiroshi

来源：Journal of Photochemistry and Photobiology A: Chemistry , 2017, 340: 8-14.

DOI：10.1016/j.jphotochem.2017.02.020

• Hydroxyl radical
• Reaction rate constant
• Ultraviolet light emitting diode
• Nitrite
• Terephthalate

We propose a simple, efficient and selective hydroxyl radical generation system based on the photolysis of submicromolar concentrations of nitrite using a high-power ultraviolet light emitting diode (UV-LED). Hydroxyl radical formation by the 6.75-W UV-LED was at least 10 times greater than that by a 300-W Xe lamp. In the UV-LED system, the hydroxyl radical formation rate from nitrite was about four orders of magnitude larger than that from nitrate and two orders of magnitude larger than that from hydrogen peroxide. Such efficient and selective hydroxyl radical formation can be attributed to the overlap of the emission spectrum of the UV-LED and absorption of nitrite. The system was used to determine the reaction rate constants between hydroxyl radicals and chemicals based on the competition method with terephthalate as the hydroxyl radical probe. The reaction rate constants between hydroxyl radicals and some low-molecular-weight organic compounds and inorganic halide salts with various reaction rate constants were determined. The values obtained ranged from 10(5) to 10(10) M-1 s(-1), and agreed well with previously reported values. The potential of the developed method to determine the reaction rate constants of hydroxyl radicals is discussed.

• 出版日期2017-5-1