THE MECHANISM OF NITRITE FORMULATION IN THE RADIATION-INDUCED OXIDATION OF AMMONIA IN AERATED AQUEOUS-SOLUTIONS

The mechanism of the radiation-induced conversion of ammonia to nitrites and nitrates in aerated aqueous solutions has been studied. The formation of the pernitrite ion, O=N-O-O-, was detected at pH greater than or equal to 10.5. The kinetics of its formation and decay were studied, and k(form) was estimated at (2.3+/-0.2).10(7) L mol(-1) s(-1). The course of decay obeys first-order kinetics; the rate constant decreases at higher pH. Radiochemical yields of pernitrite, nitrite and nitrate at various pH and initial NH3 concentrations were determined. A mechanism of ammonia oxidation in aqueous solution is proposed.