通过BCR(community bureau of reference)提取和富集系数、转移系数计算,对铀、钍在铀尾矿-植物体系中的迁移进行了研究。尾矿中U、Th的总量达205 mg/kg、141mg/kg,但其生物有效性较低,其酸溶态和可还原态的U仅占10.5%和10.8%、Th仅占0...通过BCR(community bureau of reference)提取和富集系数、转移系数计算,对铀、钍在铀尾矿-植物体系中的迁移进行了研究。尾矿中U、Th的总量达205 mg/kg、141mg/kg,但其生物有效性较低,其酸溶态和可还原态的U仅占10.5%和10.8%、Th仅占0.9%和2.8%,而残渣态U占67.7%、Th占92.1%。库区三种优势植物的各部位U、Th含量高出背景区对照值的10倍以上,明显超过了《食品中放射性物质限制浓度标准》中植物类食品的限制浓度。由于植物生长介质中仅生物有效部分的重金属能为植物所积累,因而本文提出应以富集系数BF*(等于植物中重金属含量/其生长介质中相应重金属的生物有效态含量的比值)来衡量植物对重金属的富集程度。尾矿的风化程度较弱及其U、Th生物有效性较低,植物各位U、Th的BF*均较小,三种植物对U、Th的富集程度均较低,但对钍的富集能力明显强于铀。可能受菌根对重金属的强积累能力的影响,U、Th主要富集于植物的根部,向地上部分茎、叶的转移量相对较低。目前,库区尾矿中U、Th在植物中的富集虽然不是很强,但随植物定居时间的增加,尾矿中放射性核素的生物有效性及向库区植物中迁移的能力呈增强的趋势,环境风险将逐渐增高,应引起环境管理部门的足够关注。展开更多
The extraction behavior of N, N, N’, N’-tetraisobutul-3 -oxy-dioctlylglutaramide to Uranium (VI) and Thorium (IV ) fromnitric acid solution was studied by using n-octnol and kerosene as diluent . This extractant can...The extraction behavior of N, N, N’, N’-tetraisobutul-3 -oxy-dioctlylglutaramide to Uranium (VI) and Thorium (IV ) fromnitric acid solution was studied by using n-octnol and kerosene as diluent . This extractant can not only effectively extract threevalence lanthanide and actinide, but also extract four-and six-valence actinide such as Uranium(VI) and Thorium (IV). Theresults show that the distributions of U (VI) and Th (IV) increase with the concentrations of nitric acid, Th Du . Theextraction mechanism of U(VI) and TI0V)can be inferred to be the neutral compex extraction, the structural formulas of theextractives are UO2(NO3)2. L and Th(NO3)4. L, lgKexU(VI)=(VI).455±0.09, IgK’exTh(IV)=1.66±0.04 respectively. Thisextractant can be easily synthesized and is insoluble in water, stable toward radiation nontoxic. The extracted U (VI) and Th (IV)can be effectively stripped. It can be completely decomposed without any renmants. This is good for disposal of radioactivewaste.展开更多
文摘通过BCR(community bureau of reference)提取和富集系数、转移系数计算,对铀、钍在铀尾矿-植物体系中的迁移进行了研究。尾矿中U、Th的总量达205 mg/kg、141mg/kg,但其生物有效性较低,其酸溶态和可还原态的U仅占10.5%和10.8%、Th仅占0.9%和2.8%,而残渣态U占67.7%、Th占92.1%。库区三种优势植物的各部位U、Th含量高出背景区对照值的10倍以上,明显超过了《食品中放射性物质限制浓度标准》中植物类食品的限制浓度。由于植物生长介质中仅生物有效部分的重金属能为植物所积累,因而本文提出应以富集系数BF*(等于植物中重金属含量/其生长介质中相应重金属的生物有效态含量的比值)来衡量植物对重金属的富集程度。尾矿的风化程度较弱及其U、Th生物有效性较低,植物各位U、Th的BF*均较小,三种植物对U、Th的富集程度均较低,但对钍的富集能力明显强于铀。可能受菌根对重金属的强积累能力的影响,U、Th主要富集于植物的根部,向地上部分茎、叶的转移量相对较低。目前,库区尾矿中U、Th在植物中的富集虽然不是很强,但随植物定居时间的增加,尾矿中放射性核素的生物有效性及向库区植物中迁移的能力呈增强的趋势,环境风险将逐渐增高,应引起环境管理部门的足够关注。
文摘The extraction behavior of N, N, N’, N’-tetraisobutul-3 -oxy-dioctlylglutaramide to Uranium (VI) and Thorium (IV ) fromnitric acid solution was studied by using n-octnol and kerosene as diluent . This extractant can not only effectively extract threevalence lanthanide and actinide, but also extract four-and six-valence actinide such as Uranium(VI) and Thorium (IV). Theresults show that the distributions of U (VI) and Th (IV) increase with the concentrations of nitric acid, Th Du . Theextraction mechanism of U(VI) and TI0V)can be inferred to be the neutral compex extraction, the structural formulas of theextractives are UO2(NO3)2. L and Th(NO3)4. L, lgKexU(VI)=(VI).455±0.09, IgK’exTh(IV)=1.66±0.04 respectively. Thisextractant can be easily synthesized and is insoluble in water, stable toward radiation nontoxic. The extracted U (VI) and Th (IV)can be effectively stripped. It can be completely decomposed without any renmants. This is good for disposal of radioactivewaste.
