Decomposition of aqueous ozone in the presence of aromatic organic solutes

The decomposition of aqueous ozone is mainly due to the OH. radical chain reaction. Some aromatic compounds have been found to tremendously accelerate ozone decomposition in buffered water although their direct reactions with ozone are very low. Hydrogen peroxide has been detected as an important intermediate product in this process. Therefore, a reaction pathway (aromatic ring double right arrow olefin double right arrow H2O2 double right arrow HO2-) is proposed in this study. Aromatic rings react with OH. radicals or ozone to yield olefins. The olefin formed immediately reacts with ozone and is converted to H2O2 Parts of H2O2 dissociate to HO2-, which strongly accelerates aqueous ozone decomposition. Therefore, a new chain reaction appears. The proposed reaction pathway is much faster than another promotion pathway, such as aqueous ozone decomposition promoted by methanol, formic acid or glucose. (C) 2004 Elsevier Ltd. All rights reserved.