Ru (3 +) [of Runo] ~ (3 +) Kinetic Analysis Method

With nuclear fuel burning up increasing, the yield of fission products increase, the reaction of high-yield fission products comparatively stand out. It is necessary to study of chemical behavior of ruthenium which is one of the most important fission products of nuclear fuel with high yield and long life. It is reported that ruthenium's speciation is very complicated, especially the chemical behavior and speciation in the aqueous solution is more complicated, and herewith the analysis of ruthenium in the complex solution is a still unresolved problem. Ruthenium has the remarkable characters such as forming the composition, etc. In the nitric acid the ruthenium forms RuNO³⁺ and a bit of Ru³⁺. Although study indicates that the chemical bond of Ru—NO is quite stable, Ru(bipy)₃²⁺ forms in the existence of bipy which has fine stability and water solubility. In this study the rate differential kinetic method for determination of the Ru³⁺ and RuNO³⁺ in the same sample was developed utilizing bipy as complexing agent.1,The study of kinetic of the reactions of Ru³⁺,RuNO³⁺ and bipyThe rate must be differential if different substances react with the same complexing agent. The rate differential kinetic is to use the difference of rate to determinate mixture in the same time. In general, the method is not used to determinate the reaction which rate is too high, and the reaction rate of two components must has enough difference of rate, at least, 3-4 times.1) The study results of kinetic of the reaction of Ru³⁺ and bipyThe reaction rate constant: k₁=0.131 min^-1, concentration class: n=1.0 of the reaction of Ru³⁺ and bipy. The rate equations: 2) The study results of kinetic of the reactions of RUNO³⁺ and bipyThe reaction rate constant: k₂= 3.7×10^-3(mol/L)⁰.214(min)^-1, concentration class: n₂=0.786 of the reaction of RuNO³⁺ and bipy. The rate equations:3) The study result of general equation as follows2,The study of thermodynamics of the reactions of Ru³⁺,RuNO³⁺ and bipyAlthough concentration of the Ru³⁺ and RuNO³⁺ can not be determined by the rate differential kinetic, combining with the thermodynamics, this problem can be resolved. The determination method is as follows.1) Determination of the equilibrium constant of the reaction of Ru³⁺ and bipy K₁=8.93×10¹⁰ (mol/L)^-3, the gage factor m₁=32) Determination the equilibrium constant of the reaction of RuNO³⁺ and bipy K₂=1.39×10¹¹ (mol/L)^-3, the gage factor m₂=33) Induction of the parameters of the thermodynamics in the formula determination of the concentration of C(Ru(bzpy)₃²⁺)_eq then we can get out the C₀ (C₀=C(Ru)₀+C(RuNO)₀.3,Calculation of the concentration of Ru³⁺,RuNO³⁺Combination of the rate equation and the thermodynamics equation By determination of the initial rate of reaction and the equilibrium concentration of product, we can get out C(RU)₀, C(RuNO)₀. Newton tangents method was applied since the concentration class of RuNO³⁺ is not integral value.If the system is single component, by measuring the initial rate of reaction, the equations to account the Ru³⁺ and RuNO³⁺ component as follows. When the initial rate of reaction was measured, the average concentration of 2min replaces it.With simplicity, fast response, high sensitivity, the spectrophotometry was applied combining with the rate differential kinetic in this study. The concentration of Ru(bipy)₃²⁺ was measured with the spectrophotometry. The condition was optimized such as the measuring wavelength, the reaction temperature, the acidity, the buffer and concentration, the reducer and concentration, the developer concentration and so on.The study shows the reaction of Ru³⁺,RuNO³⁺ and bipy has stable luminescence at 2min, and the difference of rate has 4.6 times which meet the requirement of the rate differential kinetic, so the 2min was chosed as the measuring point in this experiment.4 The application of sample analysis by the rate differential kineticOn the foundation of the above experiments, the sample of single component, mixing system and simulated samples was measured.1) The recovery of Ru³⁺ is 96%～105%.2) The recovery of RuNO³⁺ is 95%～106%. 3) the average relative error is -5.42%, the average relative error of component is 0.73%.4) The RSD of simulated samples is 0.65% (n=6).