Study on superoxide and hydroxyl radicals generated in indirect electrochemical oxidation by chemiluminescence and UV-Visible spectra.
The generation and transformation of radicals on the cathode of indirect electrochemical oxidation were studied by chemiluminescence (CL) and UV-Visible spectra in the reactor with a salt bridge that connected the separated chambers. The CL intensity of 4 x 10(-9) mol/L luminol on the cathode with bubbling oxygen was about seven times that of the intensity without it, which was because of the generation of reactive oxygen species (ROS). The existence of ROS, especially the generation of the superoxide radical, could be affirmed by the fact that the CL intensity of 4 x 10(-9) mol/L 2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]pyrazin-3-one with bubbling oxygen was about four times that of the intensity without it. However, there was no chemiluminescence on the anode under the same condition. The change in the UV-Visible spectra of nitro blue tetrazolium and N,N-dimethyl-4-nitrosoaniline at the cathode chamber affirmed the transformation from oxygen to superoxide and hydroxyl radicals. The mechanism of the superoxide and hydroxyl radical generation and transformation on the cathode was discussed with the help of the experimental results and relative references.
Zhang
Bo-Tao
BT
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. zhangbotao@126.com
Zhao
Li-Xia
LX
Lin
Jin-Ming
JM
D055664:Electrochemical Techniques; D016166:Free Radical Scavengers / Q000737:chemistry / Q000378:metabolism; D017665:Hydroxyl Radical / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D049449:Luminescence; D008163:Luminescent Measurements / Q000379:methods*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism*; D010545:Peroxides / Q000737:chemistry / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000737:chemistry / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D013481:Superoxides / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D013997:Time Factors
D016166:Free Radical Scavengers; D010545:Peroxides; D017382:Reactive Oxygen Species; D013481:Superoxides; D017665:Hydroxyl Radical; D010100:Oxygen