Effective separation of uranyl(II) and thorium(IV) ions from mixtures with neodymium(III) using citric acid and hexabutyl citramide as ligands grafted on mesoporous silica and polystyrene adsorbents

ABSTRACT

Adsorbents prepared by grafting citric acid or hexabutyl citramide (HBCA), either on mesoporous silica and chloromethylated polystyrene supports, show maximum selectivity (α) of 47.3, 11.9 and 4.0 for UO₂(II)/Nd(III), UO₂(II)/Th(IV) and Th(IV)/Nd(III) mixtures, respectively, in 6 M HNO₃ acid solutions. The Q_max capacity of HBCA-MS adsorbent for UO₂(II), Th(IV) and Nd(III) ions is 18.18, 12.99 and 8.62 mg.g⁻¹, respectively. Lagergren’s model parameter, Q_e,exp for UO₂(II) ions 17.88 mg.g⁻¹ and the uptake rate constant k₁ is 0.226 h^−1; whereas, Q_e,exp for Th(IV) ions is 11.29 mg.g⁻¹ and the uptake rate constant k₁ is 0.219 h⁻¹.

KEYWORDS:

• Hexabutyl citramide
• uranyl
• thorium
• neodymium selectivity
• Langmuir adsorption isotherm
• pseudo-first-order kinetic

Acknowledgments

The authors acknowledge the Department of Atomic Energy, Government of India, for financial support.