Hydrogen peroxide water sonolysis

In the sonolysis of pure water under argon, the formation rates of hydrogen radical and hydrogen peroxide are estimated to be 10.7 and 10.0 liM min-1, respectively. In an oxygen or air atmosphere, hydrogen radicals will react with oxygen as follows ... 

For every pair of OH radicals that react with PNP, one molecule of H202 is produced. This means that, in PNP solutions, the same amount of peroxide is produced from hydroxyl radical reactions as by sonolysis of pure water. In the absence of PNP, OH recombines to form hydrogen peroxide ... 

Several methods exist for the identification and quantification of the HO and H02 radicals generated by the sonolysis of water. These species can oxidize ionic moieties e.g. Fe2+ into Fe3+ (the Fricke dosimeter) and I- into iodine. In addition, either can dimerize to form hydrogen peroxide (Schemes 2 and 3), which can then be titrated using conventional techniques. The HO will also react with terephtha-late anion in aqueous solution to produce hydroxyterephthalate anion, a fluorescent material which can then be estimated using fluorimetry. 

Generally, oxidants are stable only for a short period of time therefore, electrosynthesis methods have been developed to produce oxidants on-site. Ultrasonic methods involving the application of high-intensity ultrasound are used to cause sonolysis of water to produce hydrogen peroxide and hydroxyl radicals. It should be noted that a simple combination of electrokinetics and ultrasonic waves is also investigated by some researchers, but the purpose was to enhance contaminant removal, not degradation. 

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