The shape and surface morphology of the MnO2 particles were examined by using scanning electron microscopy (SEM) (Figure ). The particles were polydispersed and of an asymmetric shape and rough surface morphology. The motion of MnO2 particles in various fuel concentrations and different chemical environments has been studied in our earlier report. In 5% H2O2 and 0.1% SDS, the average speed of MnO2 particles was 551 ± 115 µm s -1 , and can be regarded as a sufficient to enhance mass-transfer in the solution. In the decolorization experiment, 5 mg of MnO2 particles was added in 2500 µL R6G solution in a glass beaker, followed by the addition of aqueous solutions of SDS, H2O2 and pure water to make 10mL as the total reaction volume. The addition of H2O2 resulted in rapid generation of O2 bubbles that formed foam several centimeters at the top of the dye solution. The color of the bubbles started to change immediately after the adsorption of dye molecules on the bubbles via ABS mechanism. In the meantime, a generation of radical species can cause CD of the un-adsorbed dye molecules. We previously determined that CD based decolorization of methylene blue was primarily due to the loss of methyl groups from the dye structure. A similar mechanism could be responsible for the CD of R6G. It should be noted that the extent of decolorization solely due to CD cannot be reliably determined due to the simultaneous effect of ABS. However, in the absence of SDS, the contribution of ABS can be eliminated. But, this results in poor decolorization of the solution because in the absence of SDS, the particles cannot effectively undergo motion and the localized mass-transfer is not efficient. The aliquots from the reaction mixture were taken after 2 min, 10 min and 60 min intervals and diluted for the adsorption spectroscopy analysis. The resulting % decolorization was 85, 92 and ~100. The photograph of the reaction vessel is shown in Figure , whereas Figure -C show the untreated (0 min) and decolorized (60 min) solutions of R6G, respectively. To study the effect of an increase in dye concentration on decolorization efficiency, the volume of R6G solution was increased to 3500 µL by reducing the volume of pure water, keeping the concentrations of H2O2 and SDS constant. The total volume of the reaction mixture was again 10 mL. In this case, the % decolorization was recorded to be 77, 91 and ~100 after 2, 10 and 60 min intervals.