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用Ar~+激光器的4880A单色光较详细地研究了UO_2(NO_3)_2)-HCOOH-HNO_3水溶液体系中UO_3~(2+)的光化学行为。结果表明,在此体系中吸收光物质主要是甲酸铀酰络合物,甲酸铀酰络合物首先还原生成U(Ⅴ),随后歧化生成U(Ⅳ)、U(Ⅵ)。生成U(Ⅳ)的量子产额Φ主要取决于溶液中甲酸铀酰络合物的生成度α。温度升高,Φ先是增大,而后降低。在低浓度范围,U(Ⅳ)生成速率分别与UO_2~(2+)浓度或HCOO-浓度成正比。所假设的反应机理能较好地符合一些实验结果。
The photochemical behavior of UO_3 ~ (2+) in UO_2 (NO_3) _2) -HCOOH-HNO_3 aqueous solution was investigated in detail using Ar ~ + 4880A monochromatic laser. The results showed that U (Ⅴ) was first reduced to U (Ⅴ) and then disproportionated to U (Ⅳ) and U (Ⅵ). The quantum yield φ of U (Ⅳ) depends mainly on the degree of formation of uranyl formate in solution α. As the temperature increases, Φ increases first and then decreases. In the low concentration range, the formation rate of U (IV) is proportional to the concentration of UO 2 2+ or HCOO- respectively. The hypothesized reaction mechanism can better meet some experimental results.