Revisiting the Oxidizing Capacity of the Periodate-H2O2 Mixture: Identification of the Primary Oxidants and Their Formation Mechanisms.
Environ Sci Technol
; 56(9): 5763-5774, 2022 05 03.
Article
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| MEDLINE
| ID: mdl-35442651
ABSTRACT
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 (â¢OH) and singlet oxygen (1O2) contributed as the primary oxidants, and (ii) â¢OH production resulted from H2O2 reduction by superoxide radical anion (O2â¢-). PI/H2O2 exhibited substantial oxidizing capacity at pH < 5, decomposing organics predominantly by â¢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 H2O2 to yield radical intermediates, whereas H2I2O104- preferentially occurring at pH > 7 caused 1O2 generation through two-electron oxidation of H2O2. PI reduction by O2â¢- was suggested to be a key reaction in â¢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 H2O2 production achieved organic oxidation, enabling a potential strategy to minimize the use of chemicals.
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Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oxidantes
/
Peróxido de Hidrógeno
Tipo de estudio:
Diagnostic_studies
/
Prognostic_studies
Idioma:
En
Revista:
Environ Sci Technol
Año:
2022
Tipo del documento:
Article