Sorption of Neodymium and Gadolinium on Transcarpathian Clinoptilolite
V.O. Vasylechkoa,b, E.T. Stechynska a, O.D. Stashkiva, G.V. Gryshchouk a and I.O. Patsay a
aIvan Franko National University of Lviv, 6 Kyryla and Mephodia Str., 79005 Lviv, Ukraine
bLviv University of Trade and Economics, 9 Samchuka Str., 79011 Lviv, Ukraine
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The sorption properties of Transcarpathian clinoptilolite towards Nd(III) and Gd(III) under dynamic condition have been studied. Nd(III) was sorbed with the best efficiency on the uncalcined clinoptilolite samples from the solutions at pH 6.5. Clinoptilolite samples that were previously calcined at 250°C exhibit the maximal sorption capacity towards Gd(III) from the solutions at pH 9.5. Nd(III) and Gd(III) sorption on clinoptilolite mechanisms are different: Nd(III) is sorbed according to the ion-exchange mechanism, and the sorption of Gd(III) is carried out mainly by means of the adsorption of soluble hydrolyzed forms of Gd(III) on the zeolite surface. The differences in sorption mechanisms of these lanthanides give an opportunity to separate Nd(III) and Gd(III) from the solutions at pH 9.5. The maximal sorption capacity of the clinoptilolite regarding Nd(III) and Gd(III) at the optimal conditions was found to be 1810 and 6500 μg/g. The best desorbent of Nd from the clinoptilolite is 7 M HNO3 solution. The best desorbent of Gd is 1 M solution of KCl acidified to pH 2.6, which provides a 100% withdrawal of Gd from the zeolite matrix. Transcarpathian clinoptilolite is proposed as a sorbent for the preconcentration of trace amounts of Nd(III) and Gd(III) from aqueous solutions in a solid phase extraction mode.

DOI: 10.12693/APhysPolA.133.1112
PACS numbers: 68.43.-h, 07.60.Dq, 82.75.Vx