New Processes in the Environmental Chemistry of Nitrite. 2. The Role of Hydrogen Peroxide
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- 作者：Davide Vione ; Valter Maurino ; Claudio Minero ; Daniele Borghesi ; Mirco Lucchiari ; and Ezio Pelizzetti
- 刊名：Environmental Science & Technology
- 出版年：2003
- 出版时间：October 15, 2003
- 年：2003
- 卷：37
- 期：20
- 页码：4635 - 4641
- 全文大小：151K
- 年卷期：v.37,no.20(October 15, 2003)
- ISSN：1520-5851
文摘
The oxidation of nitrite and nitrous acid to 
NO2 uponirradiation of dissolved Fe(III), ferric (hydr)oxides, and nitratehas previously been shown to enhance phenol nitration.This allowed the proposal of a new role for nitrite and nitrousacid in natural waters and atmospheric aerosols. Thispaper deals with the interaction between hydrogen peroxide,a key environmental factor in atmospheric oxidativechemistry, and nitrite/nitrous acid. The reaction betweennitrous acid and hydrogen peroxide yields peroxynitrous acid,a powerful nitrating agent and an important intermediatein atmospheric chemistry. The kinetics of this reaction iscompatible with a rate-determining step involving eitherH3O2+ and HNO2 or H2O2 and protonated nitrous acid. In theformer case the rate constant between the two specieswould be 179.6 ± 1.4 M-1 s-1, in the latter case it would beas high as (1.68 ± 0.01) × 1010 M-1 s-1 (diffusion-controlled reaction). Due to the more reasonable value ofthe rate constant, the reaction between H3O2+ andHNO2 seems more likely. In the presence of HNO2 + H2O2the nitration of phenol is strongly enhanced whencompared with HNO2 alone. The nitration rate of phenolin the presence of peroxynitrous acid decreases aspH increases, thus HOONO is a potential source of atmosphericnitroaromatic compounds in acidic water droplets. Themixture Fe(II) + H2O2 (Fenton reagent) can oxidize nitriteand nitrous acid to nitrogen dioxide, which results in phenolnitration. The nitration in the presence of Fe(II) + H2O2+ NO2-/HNO2 occurs more rapidly than the one with H2O2+ NO2-/HNO2 at pH 5, where little HNO2 is available todirectly react with hydrogen peroxide. Both systems, however,are more effective than NO2-/HNO2 alone in producingnitrophenols from phenol. Another process leading to theoxidation of nitrite to nitrogen dioxide is the photo-Fenton one. It can be relevant at pH 
6, as nitrite doesnot react with H2O2 at room temperature. Under suchconditions the source of Fe(II) is the photolysis of ferric (hydr)oxides (heterogeneous photo-Fenton reaction). In thepresence of nitrite this reaction induces very effectivenitrophenol formation from phenol.
NO2 uponirradiation of dissolved Fe(III), ferric (hydr)oxides, and nitratehas previously been shown to enhance phenol nitration.This allowed the proposal of a new role for nitrite and nitrousacid in natural waters and atmospheric aerosols. Thispaper deals with the interaction between hydrogen peroxide,a key environmental factor in atmospheric oxidativechemistry, and nitrite/nitrous acid. The reaction betweennitrous acid and hydrogen peroxide yields peroxynitrous acid,a powerful nitrating agent and an important intermediatein atmospheric chemistry. The kinetics of this reaction iscompatible with a rate-determining step involving eitherH3O2+ and HNO2 or H2O2 and protonated nitrous acid. In theformer case the rate constant between the two specieswould be 179.6 ± 1.4 M-1 s-1, in the latter case it would beas high as (1.68 ± 0.01) × 1010 M-1 s-1 (diffusion-controlled reaction). Due to the more reasonable value ofthe rate constant, the reaction between H3O2+ andHNO2 seems more likely. In the presence of HNO2 + H2O2the nitration of phenol is strongly enhanced whencompared with HNO2 alone. The nitration rate of phenolin the presence of peroxynitrous acid decreases aspH increases, thus HOONO is a potential source of atmosphericnitroaromatic compounds in acidic water droplets. Themixture Fe(II) + H2O2 (Fenton reagent) can oxidize nitriteand nitrous acid to nitrogen dioxide, which results in phenolnitration. The nitration in the presence of Fe(II) + H2O2+ NO2-/HNO2 occurs more rapidly than the one with H2O2+ NO2-/HNO2 at pH 5, where little HNO2 is available todirectly react with hydrogen peroxide. Both systems, however,are more effective than NO2-/HNO2 alone in producingnitrophenols from phenol. Another process leading to theoxidation of nitrite to nitrogen dioxide is the photo-Fenton one. It can be relevant at pH 6, as nitrite doesnot react with H2O2 at room temperature. Under suchconditions the source of Fe(II) is the photolysis of ferric (hydr)oxides (heterogeneous photo-Fenton reaction). In thepresence of nitrite this reaction induces very effectivenitrophenol formation from phenol.