Reaction kinetics of nitrous acid with acetohydroxamic acid in HClO4 and HNO3 medium

The presence of nitrous acid in feed solution of PUREX process is unavoidable. Owing to its effect on the valence of plutonium and other nuclides, nitrous acid should be scavenged. The kinetics of reaction of AHA with nitrous acid was studied in HClO4 and HNO3 medium. The reaction rate equation in HClO4 and HNO3 medium is obtained as. --dc(HNO2)/dr= k·c(HNO2)1·c(AHA)0.75·c(HClO4)0.5 and --dc(HNO2)/dt=k·c(HNO2)1·c(AHA)0.25.· c(HNO3)1, respectively. In HClO4 medium, the reaction rate constant (k) is found to be (2.37±0.21) L1.25/(mol1.25·s) at θ=5 degree C, I=0.5 mol/kg. Reaction rate constant is increased slightly with the increased ion strength in the range of 0.5-2.0 mol/kg. In HNO3 medium, the reaction rate constant (k) is found to be (0.482±0.048) L1.25/(mol1.25·s) at θ=10 degree C and I= 0.5 mol/kg. Reaction rate constant is also increased slightly with the increased ion strength in the range of 0.5-3.0 mol/kg. The effect of temperature to the reaction rate is also studied. The results show that with the increase of temperature, the reaction rate increases quickly. And the activation energy is found to be 99.0 kJ/mol and 46.9 kJ/mol respectively in HNO3. (authors)