Adsorption of lanthanides and scandium ions by silica sol-gel material doped with novel bifunctional ionic liquid, trioctylmethylammonium 1-phenyl-3-methyl-4-benzoyl-5-onate

Abstract

Sol-gel processed silica doped with a novel bifunctional ionic liquid, trioctylmethylammonium 1-phenyl-3-methyl-4-benzoylpyrazol-5-onate ([A336]+[L]−), was prepared and used as a sorbent for recovery and separation of scandium and lanthanides from nitric acid solutions. The effect of HNO3 concentration in the aqueous phase on the adsorption of microquantities of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu is considered. A significant synergistic effect was observed for scandium and lanthanide adsorption from aqueous solutions. Sc(III) is sorbed from aqueous solutions much better than lanthanides(III) and separation of Sc(III) from lanthanides(III) can be achieved by simple adjusting acidity of the aqueous phase. The efficiency of lanthanide(III) adsorption from low-concentration HNO3 solutions increases with an increasing atomic number. The process of lanthanide(III) adsorption is exothermic, spontaneous and follows a pseudo-second-order kinetic model. The potentialities of the doped silica material for the preconcentration of lanthanides(III) and Sc(III) from nitrate solutions are demonstrated.