Micellar effect on the photolysis of hydrogen peroxide

Photolysis experiments were performed to quantify the effect of three anion ic surfactants on the photolysis of hydrogen peroxide (H2O2) at the ambient laboratory temperature of 22+/-1 degreesC. H2O2 photolysis in water, metha nol, and surfactant monomeric solution was also conducted to compare the ph otochemical reactivity of H2O2 in different media. Photolysis rates were hi ghest for water, followed by micellar solutions, and lowest for methanol. T he results show that the photochemical reactivity of H2O2 is les favorable in organic solvent than in water and surfactant micelles affect H2O2 photol ysis. Retarded photolysis of H2O2 in micellar solutions implies that a frac tion of H2O2 dissolved in water partitions into micellar pseudophase of sur factant. H2O2 partitioned into micelles has less photochemical reactivity a nd thus photolysis rate was retarded in the presence of micelles. Photolysi s inhibitory level by micelles was shown to be dependent on the kinds of su rfactants used in this study. In addition, the inhibitory effect by surfact ant monomers was negligible due to the absence of micelles. (C) 2001 Elsevi er Science Ltd. All rights reserved.