Decoloration and degradation of azo dye in aqueous solution supersaturated with oxygen by irradiation of high-energy electron beams

The electron beam-induced decoloration and degradation of an azo dye (Acid Red 265) in aqueous solution supersaturated with oxygen were studied. The solution, in which the dissolved oxygen concentration (DO) was increased by pressurizing with oxygen gas up to 0.3 MPa, was fed through a nozzle to a water channel under atmospheric pressure and irradiated with high-energy electron beams. It was confirmed that with high DO concentration, cleavage of aromatic rings of the dye molecules and reduction of total organic carbon were induced effectively by irradiation. The DO concentration by pressurizing under 0.3 MPa of oxygen was found to be adequate for the electron beam-induced oxidation of organic substances in water in the range of 5-14 kGy. (author)