Is the bleaching of phenosafranine by hydrogen peroxide oxidation catalyzed by silica-supported 5,10,15,20-tetrakis-(sulfonatophenyl)porphine-Mn(III) really biomimetic?

Abstract: Phenosafranine is a toxic, polluting dye, belonging to the N-phenylphenazinium class, whose inexpensive and environmentally friendly elimination from industrial effluents could be of interest. In this study we report phenosafranine degradation and concomitant decolorization of the corresponding wastewaters by H2O2 oxidation in the presence of 5,10,15,20-tetrakis(4-sulfonatophenyl)-porphine-Mn(III) catalyst immobilized on a modified silica support bearing imidazolyl functionality. Some operational features of the catalytic process are described and a chemical mechanism for the bleaching process is hypothesized. The proposed method was compared to others, based on the use of the oxidizing enzymes such as laccase, horseradish peroxidase, and lignin peroxidase.