Nitrogen-containing multifunctional copolymers as reagents to sorb rare-earth metals

Abstract

ABSTRACT N,N-Diallyl-N’-neopentanoylhydrazine was for the first time synthesized by the reaction of allylchloride with neopentanoylhydrazine. There was shown a possibility of involving the said monomer into a radical copolymerization reaction with acrylonitrile. The sorption capacity of acrylonitrile copolymers with N,N-diallyl-N’-acetylhydrazine and N,N-diallyl-N’-neopentanoylhydrazine toward light rare earth metal ions – La(+3), Sm(+3) and Ce(+3) – was investigated. The introduction of a neopentanoyl fragment into multifunctional copolymers was evinced to enhance their activity in the sorption processes of lanthanoids. Among the light rare-earth metals studied, samarium is much better extracted. With increasing concentration of sulfuric acid, the sorption capacity of both copolymers toward samarium ions enlarges and equals 150 mg∙g−1. The rate constants of external and internal diffusion within fixed intervals of time were calculated, with an essential role of both external and internal factors in the diffusion processes shown. The results obtained in exploring the conjoint adsorption of La, Ce, and Sm ions by the copolymer based on N,N-diallyl-N’-neopentanoylhydrazine evince a satisfactory separation as being attainable in acidic and alkaline media; at this point, for Cm/Ce ions the distribution coefficient βCm/Ce equals 4.78 at pH 0.3, and 2.5 at pH 11.4; for La/Ce ions it equals 3.39 at pH 0.3 and 2.2 at pH 11.4.