Studies on adsorption and separation characteristics of americium and lanthanides using a silica-based macroporous bi(2-ethylhexyl) phosphoric acid (HDEHP) adsorbent

For separating americium from lanthanides, a macroporous silica-based polymeric adsorbent (HDEHP/SiO2-P) was prepared in this study. Using this adsorbent, the adsorption characteristics of 241Am(III) and lanthanides were investigated in HNO3 solutions. The obtained results displayed that heavy lanthanides had greater adsorption towards HDEHP/SiO2-P than Ce(III) and 241Am(III). The adsorption behavior of 241Am(III) was found to be similar with Ce(III) in 0.1–0.3 M HNO3 solutions. The adsorption kinetics of Gd(III) and Ce(III) reached equilibrium within 2 h and fitted well with the pseudo-second-order kinetic model.