Effect of alcohols on elution chromatography of trivalent actinides and lanthanides using tertiary pyridine resin with hydrochloric acid–alcohol mixed solvents

Elution chromatography with a tertiary pyridine resin has been used to separate the trivalent actinides (An3+) from the lanthanides (Ln3+) using an alcoholic hydrochloric acid solvent. Trivalent Am and Cm were separated from the Ln by employing a 1 cm(Ø)×10 cm resin column with the mixed solvent system composed of concentrated hydrochloric acid (HCl) and alcohols. The distribution coefficients (Kd) and the separation factors between An and Ln (αLnAn) increased as the alcohol content of the solvent mixture increased. On the other hand, the Kd and αLnAn decreased drastically upon the addition of water to the solvent mixture. Among the four alcohols investigated (methanol, ethanol, n-propanol and n-butanol), the ethanol–HCl mixed solvent system showed the largest Kd and αLnAn. The mechanism of adsorption for An and Ln cations on the pyridine resin is discussed in addition to the results presented herein.