Salt effect on sensitized photooxidations. A kinetic approch to environmental decomposition of marine contaminants
| Autor: | María I. Gutiérrez, Susana Criado, Norman A. García |
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| Jazyk: | angličtina |
| Rok vydání: | 1998 |
| Předmět: | |
| Zdroj: | Scientia Marina, Vol 62, Iss 3, Pp 217-223 (1998) |
| Druh dokumentu: | article |
| ISSN: | 0214-8358 1886-8134 |
| DOI: | 10.3989/scimar.1998.62n3217 |
| Popis: | The salt effect on the kinetics of singlet molecular oxygen [O2(1Δg)]-mediated photooxidations of sea water contaminants was investigated. Two families of photooxidizable compounds were employed in the study: anthracene derivatives and phenols. The presence of salt (NaCl in H2O and LiCl in MeCN, in both cases in the range 0-0.45 M) produces changes in the photooxidation rate. For solvent-polarity-dependent reactions, this behavior can be predicted, by knowing the solvent-polarity dependence of the rate constant for chemical reaction of the substrates with O2(1Δ g) in non-saline solutions (kr). For the cases of photooxidations possessing solvent-polarity-independent or scantily-dependent kr values, the photooxidation rates decrease as the salt content in the solution increases, mainly due to a predominance of the physical quenching pathway. In addition, the quantum yield for O2(1 Δg) generation (ΦΔ) was determined in a series of saline solutions, in the range of 0-0.45 M in water and MeCN solutions, in the presence of NaCl and LiCl respectively. The Δ values are independent, within the experimental error on the salt content. |
| Databáze: | Directory of Open Access Journals |
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