Production of Reactive Oxygen Species on Photolysis of Dilute Aqueous Quinone Solutions

Authors

  • Shikha Garg,

    1. School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW, Australia
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  • Andrew L. Rose,

    1. Centre for Water and Waste Technology, The University of New South Wales, Sydney, NSW, Australia
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  • T. David Waite

    Corresponding author
    1. School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW, Australia
    2. Centre for Water and Waste Technology, The University of New South Wales, Sydney, NSW, Australia
      Corresponding author email: d.waite@unsw.edu.au (T. David Waite)
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Corresponding author email: d.waite@unsw.edu.au (T. David Waite)

ABSTRACT

We have examined the generation of the reactive oxygen species (ROS) superoxide and hydrogen peroxide (H2O2) by irradiation of dilute aqueous solutions of disodium anthraquinone-2-6-disulfonate (AQDS) with simulated sunlight. Irradiating a solution of AQDS in 2 mM NaHCO3 and 0.01 M NaCl produced superoxide and H2O2 at nanomolar concentrations. Experiments in which initial concentrations of dioxygen, H2O2, the superoxide radical trap nitroblue tetrazolium and the electron donor dimethyl sulfoxide were varied suggested that the interaction of solvent water with photo-excited quinone moieties produces dioxygen-reducing radicals, and that these are the primary source of ROS in the system. A kinetic model for ROS production is proposed based on our experimental data.

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