Ozone from gamma irradiation

The y-irradiation of samples in air occurs in the presence of some ozone formed by the radialysis of the air itself. (The smell of ozone is always detectable when the Gamma cell is opened.) Ozone can attack saturated polyolefins to generate radicals and initiate oxidative chains (12). The small but reproducible retardation of the oxidation of the PP films intimately wrapped in a natural rubber film is then consistent with an 03 component to the oxidation, the unsaturated rubber shielding the PP film to some extent from 03 attack by means of the rapid 0,-unsaturation reaction. As well as free radical generation, the 03-PP reaction may also lead to unstable ozonide and peroxide intermediates. 

Advanced oxidation processes (AOP) can be classified using their manner of OH radical production. The most known AOP in water treatment is the combination of ozone with H2O2. Other AOP include the UV-induced AOP (UV/H2O2, UV/ozone, UV/Ti02), Fenton and Photo-Fenton processes, sonolytically induced AOP and those AOP which create OH radicals directly from water by homolysis (gamma radiolysis/electron beam injection, VUV-irradiation). In the following chapters, each technology is discussed with respect to MTBE elimination. 

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