Photolytic and Radiolytic Oxidation of Humic Acid

Authors

  • Marcela V. Martin,

    1. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA, CCT La Plata-CONICET/UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
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  • Gustavo T. Ruiz,

    1. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA, CCT La Plata-CONICET/UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
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  • Mónica C. Gonzalez,

    1. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA, CCT La Plata-CONICET/UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
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  • Claudio D. Borsarelli,

    1. Laboratorio de Cinética y Fotoquímica. Instituto de Química del Noroeste Argentino (INQUINOA), Universidad Nacional de Santiago del Estero, Santiago del Estero, Argentina
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  • Daniel O. Mártire

    Corresponding author
    1. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA, CCT La Plata-CONICET/UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
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  • This paper is part of the Special Issue on the 21st Conference of the IAPS.

Corresponding author e-mail: dmartire@inifta.unlp.edu.ar (Daniel O. Mártire)

Abstract

The reactions of Br2˙, Br˙, HO˙ and N3˙ with Aldrich humic acid (AHA) were investigated. The Br/Br2˙ radicals were obtained in flash-photolysis experiments (λexc = 266 nm) performed with NaS2O8 solutions in the presence of bromide ions. HO˙and N3˙ radicals were generated by pulse radiolysis of N2O-saturated solutions. From the combination of a bilinear analysis and computer simulations of the absorbance traces, it was possible to obtain information on the rate constants for the reactions of Br2˙, Br˙, HO˙ and N3˙ with AHA and on the intermediate species involved in the mechanism. Evidence for the participation of phenoxyl radicals (λmax = 410 nm) is given.

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