Studies of Lanthanum(III) Nitrate Complex Sorption on the Strongly Basic Anion Exchanger Wofatit SBW Possessing Various Degrees of Crosslinking

Abstract

Rare earth elements of high purity including lanthanum play an important role in many fields of modern technology. This paper presents possibilities of the selective removal of lanthanum(III) nitrate complexes from the 90% v/v CH₃OH–10% v/v 1 and 7 M HNO₃ systems as well as the 90% v/v C₂H₅OH–10% v/v 1 and 7 M HNO₃ systems by frontal analysis on the strongly basic anion exchanger Wofatit SBW crosslinked with 2–16% DVB. The weight and bed distribution coefficients as well as the number of theoretical plates were determined from the breakthrough curves.

It has been shown that the sorption of lanthanum(III) nitrate complexes in both methanol and ethanol systems increased as the degree of crosslinkage increased from 2% to 8% DVB, and then decreased with further increase in crosslinking. This can be interpreted in terms of a ‘sieve action’ arising from the partial removal of large complex ions from the anion-exchanger phase [not all the ion-exchange centres are accessible to La(NO₃)^3-n_n species].