This study reexamined the mechanisms for oxidative organic degradation by the binary mixture of periodate and H2O2(PI/H2O2) that was recently identified as a new advanced oxidation process. Our findings conflicted with the previous claims that (i) hydroxyl radical (•OH) and singlet oxygen (1O2) contributed as the primary oxidants, and (ii) •OH production resulted from H2O2reduction by superoxide radical anion (O2•-). PI/H2O2exhibited substantial oxidizing capacity at pH < 5, decomposing organics predominantly by •OH. The likelihood of a switch in the major oxidant under varying pH conditions was revealed. IO4-as the major PI form under acidic conditions underwent one-electron reduction by H2O2to yield radical intermediates, whereas H2I2O104-preferentially occurring at pH > 7 caused 1O2generation through two-electron oxidation of H2O2. PI reduction by O2•-was suggested to be a key reaction in •OH production, on the basis of the electron paramagnetic resonance detection of methyl radicals in the dimethyl sulfoxide solutions containing PI and KO2, and the absence of deuterated and 18O-labeled hydroxylated intermediates during PI activation using D2O and H218O2. Finally, simple oxyanion mixing subsequent to electrochemical PI and H2O2production achieved organic oxidation, enabling a potential strategy to minimize the use of chemicals.
|Number of pages||12|
|Journal||Environmental Science and Technology|
|Publication status||Published - 2022 May 3|
Bibliographical noteFunding Information:
This work was supported by a National Research Foundation of Korea Grant, funded by the Korean government [Grant no. NRF-2021R1A2C2003763] and by the Technology Advancement Research Program, funded by the Ministry of Land, Infrastructure, and Transport of the Korean government [Grant 21CTAP-C157292-02].
© 2022 American Chemical Society. All rights reserved.
All Science Journal Classification (ASJC) codes
- Environmental Chemistry