硅基阴离子交换剂吸附Tc(Ⅶ)

Adsorption of Tc(Ⅶ) From Nitric Acid Medium by Silica-Based Anion Exchanger

摘要: 主要研究了硅基阴离子交换剂（以下简称SiR₄N）在硝酸溶液中对Tc(Ⅶ)的吸附行为及其影响因素。结果表明，在0.50mol/L HNO₃介质中，SiR₄N对Tc(Ⅶ)的吸附分配系数为370mL/g，吸附平衡时间为35min；机理研究表明，Tc(Ⅶ)主要以TcO^-₄阴离子的形式被SiR₄N吸附；SiR₄N对Tc(Ⅶ)的吸附等温线基本符合Langmuir吸附等温线，属单分子层吸附，吸附热为-18.48kJ/mol；在0.50mol/L HNO₃介质中SiR₄N对Tc(Ⅶ)的静态饱和吸附量为0.30mmol/g(干)。

Abstract: The adsorption of Tc(Ⅶ) and its mechanism by the silica-based anion exchanger (SiR 4N) were investigated in the aqueous solution of nitric acid. It is found that the adsorption mechanism of Tc(Ⅶ) on SiR₄N accords with Langmuir isotherm, which means a monolayer adsorption. According to Clausius-Claperon equation, the adsorption heat ΔH is estimated to be -18.48kJ/mol. When the concentration of nitric acid is 0.50 mol/L, the saturated adsorption of Tc(Ⅶ) on dry SiR₄N reaches 0.30 mmol/g at 25℃.