硫酸溶液中铀酰离子的激光光化还原

PHOTOREDUCTION OF URANYL IONS IN SULFURIC ACID MEDIUM WITH LASER

摘要: 本文研究了硫酸溶液中铀酰离子的激光光化还原,选用CW He-Cd激光器的波长为4416(?),测得25℃时生成U(Ⅳ)的量子产额为0.69±0.03;研究了乙醇,硫酸和铀酰离子浓度对量子产额的影响。在C_2H_5OH>0.5M、H_2SO_4>2.0M和UO_2~(2+)>7.0×10~(-3)M时,它们的浓度变化对量子产额影响不大。在25℃和1.7M乙醇浓度下,测定了硫酸中氢离子和铀酰离子浓度与反应速率的关系,得到在一定条件下光化还原生成U(Ⅳ)的速率ν与H~+和U(Ⅵ)的关系式为: v=kH~+°UO_2~(2+)~6 由实验求得上式中常数a和b分别为0.16和1.3,计算出表观反应速率常数为4.1×10~(-5)(M,sec,mW)。

Abstract: The photoreduction of uranyl ions in sulfuric acid with a CW He-Cd laser at 4416 A has been investigated. A quantum yield of 0.69+0.02 is obtained for the production of U (IV) at 25℃. The effect of the concentrations of ethanol, sulfuric acid and uranyl ion on the quantum yield has been discussed. If U (VI) >7.0×10-3M, C2H5OH> 0.5M, and H2SO4>2.0M, the concentration effects for quantum yield are negligible. The dependence of reaction rate on the concentrations of sulfuric acid and uranyl ion has been studied. The rate of production of U (IV) depends on the concentration of H+ and UO22+ and the corresponding rate equation iswith a and b equal to 0.16 and 1.3 respectively. The apparent rate constant, k (M, sec, mW), is calculated to be 4.1×10-5 at 25℃.