Uptake of Sc 3+ and La 3+ from aqueous solution using ethylenediaminetetraacetate-intercalated Cu–Al layered double hydroxide reconstructed from Cu–Al oxide

Abstract

A Cu–Al layered double hydroxide intercalated with ethylenediaminetetraacetate (edta·Cu–Al LDH) was prepared by suspending Cu–Al oxide, obtained by the calcination of CO 3 2 − -intercalated Cu–Al LDH, in edta solution. It was found that the reconstruction of Cu–Al oxide to Cu–Al LDH was promoted with an increase in the temperature and time. The reaction in the pH range of around 8 suggests that Hedta 3− was intercalated in the interlayer of Cu–Al LDH. Edta·Cu–Al LDH was found to take up rare metal ions such as Sc 3+ and La 3+ in an aqueous solution at a pH of around 6–6.5. The uptake of Sc 3+ was caused not only by the chelating function of Hedta 3− in the interlayer but also by the chemical behavior of Cu–Al LDH itself. On the other hand, the uptake of La 3+ was caused only by the chelating function of Hedta 3− in the interlayer. The Hedta 3− in the interlayer of edta·Cu–Al LDH had the potential to form a chelate complex more preferentially with Sc 3+ than with La 3+.