Decomposition of aqueous ozone in the presence of aromatic organic solutes

Abstract

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=>olefin=>H(2)O(2)=>HO(2)(-)) 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 H(2)O(2). Parts of H(2)O(2) dissociate to HO(2)(-), 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.