ELIMINATION OF BENZENE AND CHLOROBENZENES BY PHOTODEGRADATION AND OZONATION PROCESSES

Abstract

Benzene (B) and two representative chlorobenzenes (1,4-dichlorobenzene (DCB) and 1,2,3-trichlorobenzene (TCB)) were oxidized by means of UV irradiation alone, ozone alone, and the combinations UV/H₂O₂ and O₃/H₂O₂. In the single photolytic process, the influence on the photodegradation of the pH, temperature, and type of radiation source used was established. A kinetic study was performed by evaluating the first-order rate constants and the quantum yields. The effect of the additional presence of hydrogen peroxide was pointed out in the combined process UV/H₂O₂,with the determination of the specific contribution of the radical pathway to the overall photodegradation system. In the oxidation by ozone based systems (ozone alone and the combination O₃/H₂O₂), the rate constants at 20°C for the reaction of each compound with ozone and hydroxyl radicals were determined.

Keywords:

• Benzene
• Chlorobenzenes
• Hydroxyl radicals
• Kinetic
• Ozone
• UV radiation

Acknowledgment

This research was supported by the Ministerio de Educación y Ciencia de España, through the Project CTQ 2004-00961/PPQ.

Notes

*Experiments with the polychromatic radiation source: X_P = conversions obtained at 10 min of reaction.