Articles | Volume 9, issue 13
Atmos. Chem. Phys., 9, 4229–4237, 2009
https://doi.org/10.5194/acp-9-4229-2009
Atmos. Chem. Phys., 9, 4229–4237, 2009
https://doi.org/10.5194/acp-9-4229-2009

  02 Jul 2009

02 Jul 2009

Photoinduced oxidation of sea salt halides by aromatic ketones: a source of halogenated radicals

A. Jammoul, S. Dumas, B. D'Anna, and C. George A. Jammoul et al.
  • Université de Lyon, Lyon, 69626, France; université Lyon 1, Lyon, 69626, France; CNRS, INSU, UMR5256, IRCELYON, Institut de recherches sur la catalyse et l'environnement de Lyon, Villeurbanne, 69626, France

Abstract. The interactions between triplet state benzophenone and halide anion species (Cl, Br and I have been studied by laser flash photolysis (at 355 nm) in aqueous solutions at room temperature. The decay of the triplet state of benzophenone was followed at 525 nm. Triplet lifetime measurements gave rate constants, kq (M−1 s), close to diffusion controlled limit for iodide (~8×109 M−1 s), somewhat less for bromide (~3×108 M−1 s) and much lower for chloride (<106 M−1 s). The halide (X) quenches the triplet state; the resulting product has a transient absorption at 355 nm and a lifetime much longer than that of the benzophenone triplet state, is formed. This transient absorption feature matches those of the corresponding radical anion (X2). We therefore suggest that such reactive quenching is a photosensitized source of halogen in the atmosphere or the driving force for the chemical oxidation of the oceanic surface micro layer.

Download
Altmetrics
Final-revised paper
Preprint