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

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℃.