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 Am-241(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 Am-241(III). The adsorption behavior of Am-241(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.