毛细管法测定^(99)Tc在压实皂土中的吸附分配系数和表观扩散系数

Determination of Distribution and Diffusion Coefficients of ^(99)Tc in Compacted Bentonite by Capillary Method

利用毛细管法研究了温度和皂土密度对99 TcO-4 在压实皂土中的吸附分配系数和表观扩散系数的影响,实验结果符合Fick’s定律。研究结果表明,99 TcO-4 在压实皂土中的吸附分配系数和表观扩散系数随温度升高而增加,随皂土密度的增加而减小。温度和皂土的密度(皂土柱的空隙率)对放射性核素的吸附和迁移起着重要作用。

Effects of temperature and bentonite density on the sorption distribution coefficients and apparent, diffusion coefficients of 99Tc in compacted bentonite are studied by using capillary method. The results fit the Pick's second law very well and are in good agreement with the literature data under similar experimental conditions. The results indicate that apparent diffusion coefficients and sorption distribution coefficients of 99TcO4- in compacted bentonite decrease with the increase in bentonite density and increase with the increase in temperature. Temperature and the compactness of bentonite, i.e., the porosity of compacted bentonite, contribute significantly to the migration and sorption of radionuclides in compacted bentonite.