【摘要】 用批式法研究了大气条件下99Tc在Fe,Fe2O3和Fe3O4上的吸附行为,考察了吸附平衡后溶液中99Tc的存在价态。实验结果表明:随着溶液pH值(5～12)、CO2-3浓度(1×10-8～1×10-2mol/L)的增大,99Tc在Fe上的吸附比减小;溶液pH值、CO2-3浓度的变化基本不影响99Tc在Fe2O3和Fe3O4上的吸附;99Tc在这3种吸附材料上的吸附行为均可用Freundlich吸附等温式表示;当Fe作吸附材料时,吸附平衡后99Tc主要以Tc(Ⅳ)的形式被吸附,当Fe2O3和Fe3O4作为吸附材料时,99Tc主要以Tc(Ⅶ)的形式被吸附。更多还原

【Abstract】 The absorption behavior of ⁹⁹Tc on Fe, Fe₂O₃ and Fe₃O₄ powders from aqueous ⁹⁹TcO^-₄ （solutions） is studied by batch method in atmospheric conditions. After the adsorption reaches （equilibrium）, the valence state of ⁹⁹Tc in the aqueous solution is examined by extraction with tetraphenylarsonium chloride. The experimental results show that the adsorption ratio of ⁹⁹Tc on iron powders decreases with the increase of pH （in the range of 5～8） and of CO^2-₃ concentration (in the range of 1×10^-8～1×10^-2 mol/L). In opposite, the two factors have no significant influence on the absorption of ⁹⁹Tc on both Fe₂O₃ and Fe₃O₄ powders. The adsorption isotherms of ⁹⁹TcO^-₄ on Fe, Fe₂O₃ and Fe₃O₄ powders can be well described by the Freudlich’s equation. The major valence state of ⁹⁹Tc is deduced to be Tc（Ⅳ） when iron powders is used as the absorbent. In the case of Fe₂O₃ or Fe₃O₄ as an absorbent, the ⁹⁹Tc remains as the TcO^-₄ form.更多还原