大气与低氧条件下锝在辉锑矿上的吸附行为和机理研究

Study on Sorption of Radioactive Technetium on Stibnite Under Aerobic and Anaerobic Conditions

用批式实验法研究99TcO- 4在辉锑矿上的吸附行为 ,并用稀硫酸解吸法和酸性条件下的吸附法对吸附机理进行探讨。研究结果表明 :在低氧与大气条件下 ,辉锑矿对花岗岩预平衡水中的TcO- 4具有较强的吸附能力 ;在酸性条件下 ,TcO- 4在辉锑矿上几乎不吸附 ,但随着酸度的降低 ,吸附比增大。体系液相的pH、Eh条件对99TcO- 4的吸附不产生决定性影响 ,稀硫酸难以将吸附在辉锑矿上的锝解吸下来 ,加入氧化剂可加快锝的解吸。

The sorption behaviors of radioactive technetium on stibnite are studied with batch experiment. In order to determine the possible sorption mechanism, dilute sulfuric acid is used to dissolve the technetium adsorbed on stibnite and a series of sorption experiments are carried out under acidic conditions. Both aerobic and anaerobic conditions have been employed, and the results show that a significant sorption of technetium on stibnite is found under aerobic and anaerobic conditions, and the sorption on the mineral is supposed to be due to the reduction of TcO - 4 to insoluble TcO 2· n H 2O. No more than 10 percent of the reduce/sorbed technetium is desorped by dilute sulfuric acid. On addition of H 2O 2 to the leach solution a sudden increase in the technetium concentration is observed. Little or no sorption is found at higher acidity and the sorption ratio increase with the decrease of the concentratin of sulfuric acid.