Adsorption Performance and Mechanism of Pu(Ⅳ) by Silica-Based Quaternary Ammonium Material

The adsorption performance and mechanism of silicabased quaternary ammonium material (SiR₄N) were investigated by adsorption of Pu（Ⅳ） in 4 mol/L nitric acid solution. The adsorption isotherm of Pu（Ⅳ）on SiR₄N could be simulated well using Langmuir isotherm. According to Clausius-Claperon equation, adsorption heat estimated from the slope of ln K_d vs 1/ T plot is ΔH ＝-7.23 kJ/mol, which is exothermic reaction. Distribution ratios (D) and the amount of functional group can be expressed as lg D =3.43+1.74lg n (SiR₄N⁺ )，, and the slope is close to 2. It is concluded that the adsorption of Pu（Ⅳ） on SiR₄N in nitric acid solution belongs to anion ion exchange, and most of ［Pu(NO₃)₆］^2-are absorbed on SiR₄N.