Pu(Ⅳ)的光化学行为
THE PHOTOCHEMICAL BEHAVIOUR OF Pu(Ⅳ)
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摘要: 本文研究了H~+,N0_2~-对在μ=3的Pu(Ⅳ)高氯酸溶液中的光化学行为的影响。证明NO_3~-对光氧化有较大的影响。在63℃和μ=3时,对有无紫外光作用时Pu(Ⅳ)歧化反应进行了比较,结果表明紫外光照射有利于歧化反应的进行,二者反应浓度商的比值在H~+为1.0,1.5,2.0和3.0mol/l时分别为2.2×10~3,4.15×10~2,1,98×10~2和3.16×10~2。 还研究了甲醇、乙醇、UO~(2+)和Fe~(3+)对Pu(Ⅳ)在HNO~3溶液中光化学行为的影响。发现Fe~(3+)的加入可使Pu(Ⅵ)量显著减少,当Fe~(3+)≥0.038mol/l时,可使Pu(Ⅵ)的生成量由>80％降低到<10％。对Fe~(3+)抑制Pu(Ⅵ)生成的机理进行了初步探讨。Abstract: The effects of concentration of H+ and NO3- on the photochemical behaviour of Pu(Ⅳ) in perchloric acid solution (ionic strength = 3) have been investigated. The results show that the photochemical oxidation of Pu(Ⅳ) to Pu(Ⅵ)is obviously promoted by nitrate ion.Results of the study of thermo-disproportionation of Pu(Ⅳ) in perchloric acid solution (ionic strength = 3)at 63℃ and irradiation of ultraviolet beam at the same experimental condition show that the light irradiation with ultraviolet beam promotes the disproportionation of Pu (Ⅳ) , and ratios of reaction concentration quotient Pu(Ⅲ)2-Pu(Ⅵ)/Pu(Ⅳ)3 arc determined as 2.2×103, 4.15×102, 1.98×102 and 3.16×102 at H+ equal to 1.0, 1.5, 2.0 and 3.0 mol/1.The effects of CH3OH, C2H5OH, UO22+ and Fe3+ on the photochemical behaviour of Pu(Ⅳ) in nitrate solution are also studied. The results show that the Pu(Ⅳ) oxidation to Pu(Ⅵ) is inhibited by ferric ion, the quantity of Pu(Ⅵ) can be decreased from 80% to 10% if the concentration of ferric ion is 0.038 mol/1. The probable reason of inhibition of Pu(Ⅳ) oxidation to Pu(Ⅵ) by ferric ion is discussed.
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