Interplay of physically different properties leading to challenges in separating lanthanide cations – an <i>ab initio</i> molecular dynamics and experimental study

The lanthanide elements have well-documented similarities in their chemical behavior, which makes the valuable trivalent cations (Ln(III)) particularly difficult to separate from each other water. In this work, we apply ab initio molecular dynamics simulations compare free energies (Delta G(ads)) associated with adsorption of silica surfaces at a pH condition where SiO- groups are present. predicted Delta G(ads) for lutetium (Lu(III)) and europium (Eu(III)) similar within statistical uncertainties; is qualitative agreement our batch measurements on silica. This finding remarkable because two exhibit hydration G(hyd}) that differ by >2 eV, different numbers, hydrolysis behavior far surfaces. We observe similarity Lu(III) Eu(III) result delicate cancellation between difference G(hyd})), binding propose disrupting end points, either adsorbed or completely desorbed lanthanides (e.g., via nanoconfinment mixed solvents), will lead effective Ln separation.