Salt effect on sensitized photooxidations. A kinetic approch to environmental decomposition of marine contaminants

Authors

  • María I. Gutiérrez Departamento de Química. Facultad de Ciencias Naturales. Universidad Nacional de la Patagonia
  • Susana Criado Departamento de Química. Universidad Nacional de Río Cuarto
  • Norman A. García Departamento de Química. Universidad Nacional de Río Cuarto

DOI:

https://doi.org/10.3989/scimar.1998.62n3217

Abstract


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.

Downloads

Download data is not yet available.

Downloads

Published

1998-09-30

How to Cite

1.
Gutiérrez MI, Criado S, García NA. Salt effect on sensitized photooxidations. A kinetic approch to environmental decomposition of marine contaminants. Sci. mar. [Internet]. 1998Sep.30 [cited 2024Apr.15];62(3):217-23. Available from: https://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/967

Issue

Section

Articles