Thermodynamic study of the complexation of uranium(VI) with nitrate at variable temperatures

被引:41
作者
Rao, Linfeng [1 ]
Tian, Guoxin [1 ]
机构
[1] Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA
关键词
Uranium(VI); Nitrate; Complexation; Temperature effect;
D O I
10.1016/j.jct.2008.02.013
中图分类号
O414.1 [热力学];
学科分类号
摘要
Complexation of uranium(VI) with nitrate was studied at variable temperatures by spectrophotometry and microcalorimetry. The complexation is weak and the stability constant of a 1:1 complex, UO2NO3+, was found to slightly increase as the temperature was increased from 25 to 70 degrees C. The molar enthalpy of complexation at 25 degrees C was determined by microcalorimetry to be small and positive, (3.9 +/- 0.5) kJ . mol(-1), in good agreement with the trend in the stability constant at different temperatures. Discussions were made on topics including weak complexation vs. ionic medium effect and outer sphere vs. inner sphere complexes. Specific ion interaction (SIT) approach was used to obtain the stability constants at infinite dilution and variable temperatures. (C) 2008 Elsevier Ltd. All rights reserved.
引用
收藏
页码:1001 / 1006
页数:6
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