Abstract
In this paper we show that bromide scavenges the ·OH radicals formed upon photolysis of nitrate, before they leave the solvent cage. Bromide can thus inhibit the in-cage recombination between ·OH and ·NO2. The consequence is an increased generation of ·NO2 and nitrite and of Br2 −· + ·OH, compared to ·OH alone in the absence of bromide. We show that this effect compensates for the lower reactivity of Br −·2 compared to ·OH toward certain organic substrates, e.g. phenol and tryptophan. Our findings could lead to a deep revision of the present views of the role of bromide in saltwater photochemistry.
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Acknowledgments
We acknowledge financial support by PNRA—Progetto Antartide, CIPE—Regione Piemonte (project A142), INCA (WG GLOB-CHEM), and by MIUR—Progetto India for the bursary of Radharani Das.
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Das, R., Dutta, B.K., Maurino, V. et al. Suppression of inhibition of substrate photodegradation by scavengers of hydroxyl radicals: the solvent-cage effect of bromide on nitrate photolysis. Environ Chem Lett 7, 337–342 (2009). https://doi.org/10.1007/s10311-008-0176-8
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DOI: https://doi.org/10.1007/s10311-008-0176-8