Performance and selectivity of the terephthalic acid probe for *OH as a function of temperature, pH and composition of atmospherically relevant aqueous media - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Photochemistry and Photobiology A: Chemistry Année : 2011

Performance and selectivity of the terephthalic acid probe for *OH as a function of temperature, pH and composition of atmospherically relevant aqueous media

Résumé

In the present study, we investigated the performance and selectivity of terephthalic acid (TA) as a trapping molecule for the laboratory quantification of photogenerated *OH in synthetic water (where the organic and inorganic concentration is perfectly controlled), adopted as a proxy of natural atmospheric water (i.e. cloud droplets). TA reacts with *OH to yield 2-hydroxyterephthalic acid (TAOH). First, we focused our investigation on the reactivity of TA as a function of pH and temperature of laboratory-made solutions, by using nitrate and hydrogen peroxide as photochemical *OH sources. For the pH dependence of the TAOH formation yield (YTAOH), by fitting data using linear regression we obtained the relationship YTAOH = (0.0248 ± 0.0059)pH + (0.046 ± 0.035) at T = 288 K, in the pH range 3.9-7.5. For the temperature dependence we got YTAOH = (0.0059 ± 0.0011)T − (1.50 ± 0.31), between 278 and 303 K at pH 5.4. Furthermore, the performance and selectivity of TA were assessed in the presence of different photochemical *OH sources (nitrate and H2O2) and scavengers (alcohols and carboxylic acids) at variable concentrations. These species are naturally present in the atmospheric aqueous phase. From these experiments we obtained the second-order reaction rate constant between TA and *OH, kTA,*OH = (4.0 ± 0.1) × 109M−1 s−1 in aerated solution, at pH 6.0 and 293 ± 2 K.
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hal-00694951 , version 1 (07-05-2012)

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  • HAL Id : hal-00694951 , version 1

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Tiffany Charbouillot, Marcello Brigante, Gilles Mailhot, Pratap Reddy Maddigapu, Claudio Minero, et al.. Performance and selectivity of the terephthalic acid probe for *OH as a function of temperature, pH and composition of atmospherically relevant aqueous media. Journal of Photochemistry and Photobiology A: Chemistry, 2011, pp.70-76. ⟨hal-00694951⟩
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