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/SiO-P) was prepared in this study. Using this adsorbent, the adsorption characteristics of Am(III) and lanthanides were investigated in HNO solutions. The obtained results displayed that heavy lanthanides had greater adsorption towards HDEHP/SiO-P than Ce(III) and Am(III). The adsorption behavior of Am(III) was found to be similar with Ce(III) in 0.1-0.3 M HNO 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. [ABSTRACT FROM AUTHOR]