Reaction of ferricyanide and methyl viologen with free radicals produced by ultrasound in aqueous solutions

Abstract

The redox reactions of organic radicals, with Fe(CN) 63 - and methyl viologen, generated from the sonochemical decomposition of aliphatic alcohols in aqueous solutions, have been studied. The number of radicals produced was found to relate to the amount of adsorbed alcohol molecules (Gibbs surface excess) at the gas-aqueous solution interface for any bulk solution concentration of the alcohol. The majority of the radicals produced stem from the thermal degradation of the alcohol molecules that have entered imploding cavitation bubbles. The maximum rate of reduction at 355 kHz, of Fe(CN) 63 -, was 2.6 ± 0.3 μM min -1, whereas for methyl viologen, it was 1.2 ± 0.3 μM min -1 under the condition..