Am(Ⅲ)与腐殖酸配位行为的研究

    • 摘要: 采用萃取法研究了不同pH值的0.1mol/kgNaClO4溶液中,Am(Ⅲ)与腐殖酸的配位行为。实验结果表明,Am(Ⅲ)-腐殖酸配合物的累积稳定常数与溶液pH值有关,配位比为1∶2。不同pH值条件下,Am(Ⅲ)与腐殖酸配合物的累积稳定常数为:lgβ1=6.56±0.05,lgβ2=10.77±0.13(pH=4.0);lgβ1=7.94±0.11,lgβ2=11.80±0.21(pH=5.0);lgβ1=10.74±0.28,lgβ2=12.88±0.49(pH=6.0);lgβ1=12.85±0.30,lgβ2=14.80±0.62(pH=7.0);lgβ1=14.88±0.48,lgβ2=15.65±0.69(pH=8.0);pH值的变化与Am(Ⅲ)-腐殖酸配合物累积稳定常数间的关系为:lgβ1=2.16(±0.98)pH-2.34(±0.93),lgβ2=1.28(±1.04)pH+5.52(±1.21)。

       

      Abstract: COMPLEX FORMATION OF AMERICIUM(Ⅲ)WITH HUMIC ACIDZhang Yingjie Zhao XinWei Liansheng Lin Zhangji(China Institute of Atomioc Energy,P.O.Box 275(93),Beijing 102413)ABSTRACTThe presence of humic substances in natural waters will modify the migration behavior of actinides in the goesphere due to the strong reaction properties of these ligands with actinides.Therefore,the possible reactions of humic acid with actinides have been studied widely in recent years.The complex formation of Am(Ⅲ) with humic acid is studied with solvent extraction technique.The experiments are performed in the pH range from 4.0 to 8.0 in 0.1 mol/kg NaClO4 solution at ambient temperature.Experimental results show that the complex formation constants of Am(Ⅲ) with humic acid are varied with the variation of pH value in solution. 1∶2 complex is obtained in the experiments and the complex formation constants determined at each pH are:lgβ1=6.56±0.05,lgβ2=10.77±0.31 at pH=4.0. lgβ1=7.94±0.11,lgβ2=11.80±0.21 at pH=5.0. lgβ1=10.74±0.28,lgβ2=12.88±0.49 at pH=6.0. lgβ1=12.85±0.30,lgβ2=14.80±0.62 at pH=7.0. lgβ1=14.88±0.48,lgβ2=15.65±0.69 at pH=8.0,respectively. The dependence of the complex formation constant on pH is:lgβ1=2.16(±0.98)pH-2.34(±0.93),lgβ2=1.28(±1.04)pH+5.52(±1.21),respectively.Keywords 241Am(Ⅲ) Humic acid Extraction Complex HDEHP Stability constant

       

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