Lanthanide distribution coefficients on Dowex chelating resin A-1

The results of this experimentation are in agreement with a previously observed elution sequences for La3+ and Lu3+ on Dowex A-1 chelating resin[1]. At 25·00°C, pH 2·00 and μ = 0·100 (NaCl), the selectivity of the resin for trivalent lanthanide ions was to be La3+ < Pr3+ < Nd3+ > Sm3+ > Gd3+ ∼ Dy3+ < Er3+ > Yb3+. Anomalities in selectivity appear to arise from a positive increase in the electrical contribution to ΔG. Such an increase may be associated with the phase change Lnaqueous3+ → Lnresin3+. When the observed distribution coefficients were corrected for this this effect, rather good agreement was obtained between the lanthanide-Dowex A-1 and the simpler monomeric chelate stability trends.