Vol 2, Issue 4 (2018)


Ozone is widely used as an efficient and cost-effective oxidant and disinfectant in drinking and waste-water treatment. Besides its direct reactivity toward inorganic and organic pollutants, a significant part of the ozonation effectiveness is due to the generation of reactive radicals (hydroxyl radical HO°, superoxide anion O2°-, etc.) during its decomposition in water. This decomposition is usually initiated by both the hydroxide and the hydroperoxide (HO2-) anions. The capacity of HO2- to decompose O3 is advantageously implemented in the peroxone process. The OH° radical generation from a combination of H2O2 and O3 is effective for degradation and mineralization of many micro-pollutants and recalcitrant compounds (drugs, endocrine disruptorsm dyes, pesticides, etc.). However, kinetics constant of the initiation of O3 decomposition by HO2- to illustrate the fast reaction for OH° generation is still controversial in literatures.

The purpose of this study is to confirm the kinetics constant of this initiated reaction by reactive absorption using a jacketed, stirred-cell reactor, operated semi-continuously. Based on the dissolved H2O2 concentration decreasing and the outlet ozone concentration consumed, the stoichiometry of the initiation reaction was determined, and a fast pseudo – first order absorption regime was obtained from the chemical conditions. As a result, the reaction rate constant k of the fast initiation reaction of ozonation with hydrogen peroxide is determined in a range from 2.64×106 to 2.81×106 L mol-1 s-1 at 25°C, depending on the correlation of ozone, Henry’s law constant in water.


  • Thom Dang Thi
  • Pierre-François Biard
  • Tuyen V. Trinh
  • Annabelle Couvert

Key words:

  • Ozone
  • Hydrogen peroxide
  • Reactive absorption
  • Kinetics constant

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