Photodegradation of methylene blue dye by the UV/H2O2 and UV/acetone oxidation processes

The photodegradation of methylene blue (MB) dye in aqueous solutions was investigated using a laboratory-scale UV lamp in the presence of hydrogen peroxide (H2O2). Different initial concentrations of dyes (10, 20, 30, 40 ppm) were investigated using different doses of H2O2. Substantial decolorization of the dye was reached using UV/H2O2, where neither UV nor H2O2 alone was appreciably able to decolorize any of the dyes. The optimum dose of H2O2 increased with the increase of the initial concentration of the dye. The experimental decoloration kinetics data followed the pseudo-first-order reaction model. The time of decoloration increased with an increase in the initial dye concentration. The effect of the presence of photosensitized material such as acetone on the decoloration rate of the MB dye was also examined. Increasing acetone concentration shortened the time needed to completely decolorize MB solutions. The oxidation role of hydroxyl-free radicals was evaluated using sodium carbonate.