Radiation-induced Degradation of Diethylstilbestrol by Electron Beam Irradiation

The degradation kinetics and primary radiolytic degradation mechanism of diethylstilbestrol by electron beam irradiation have been investigated. The results show that the electron beam irradiation is an effective method to reduce diethylstilbestrol. The degradation of diethylstilbestrol in acetonitrile/water oxidative system is higher than in methanol/water reductive system at the same absorbed dose. Furthermore, the study indicates that the decomposition rate increased with the addition of H2O2 to the solution. These illustrate hydroxyl radical (center dot OH) might play a crucial role in degradation of diethylstilbestrol. The removal of diethylstilbestrol followed pseudo-first-order kinetic in acetonitrile/water solution and the kinetics rate constant decayed exponentially with increasing initial concentration of diethylstilbestrol. The degradation rate of diethylstilbestrol decreased with increasing absorbed dose in acetonitrile/water solution, which was illustrated by changes in specific reduction efficiency and increased with decreasing initial concentration at a constant absorbed dose. Different systems saturated with O-2 or N-2 did not lead to an effectively increase in the degradation of diethylstilbestrol. The solution in alkaline condition was benefit for the degradation of diethylstilbestrol. Organic acids produced by the degradation of diethylstilbestrol were identified using ion chromatography, such as acetic acid, formic acid and oxalic acid. Diethylstilbestrol radiolysis may be caused by that center dot OH attacked diethylstilbestrol leading to the open of benzene ring and generation of organic acids.