Radiolytic degradation of chlorobenzene in aerated and deoxygenated aqueous solutions.

Radiation-induced degradation of chlorobenzene was conducted at 0.1, 0.4, 0.5, 0.7, and 1.0 mmol/dm3 concentrations in aerated environment and at 1.0 mmol/dm3 in oxygen-free and N2O-saturated solutions. The results demonstrated that the elimination of chloride is important when the solution is oxygen free, because the [Formula: see text] attacks at the ipso position of the chloro group produces hydrochloric acid. The degradation was affected to a large extent by the concentration and to a lesser extent by the presence or absence of oxygen in the solutions which were irradiated. Thereby, the degradation occurred faster in the solutions with air and without oxygen and more slowly in the saturated solution with N2O. Some by-products were identified using an HPLC-UV-mass system. In addition, it was found that there is a linear correlation between the ln C/C0 and the dose, indicating that the radiolytic degradation followed pseudo-first-order reaction kinetics. The radiolytic oxidation was followed by the chemical oxygen demand (COD) test. The COD decreases when the solute concentration increases. The COD results were for a 0.47 mmol/dm3 of 5.94 mg O2 dm-3 kGy-1 and for 0.09 mmol/dm3 of 7.45 mg O2 dm-3 kGy-1.