Ion-exchange properties of lithium aluminium layered double hydroxides

Abstract

The synthesis of layered lithium aluminium hydrotalcite-like materials is described along with different anion exchange procedures for the preparation of materials intercalated with chloride, nitrate and vanadate. The products have been characterised using elemental chemical analysis, powder X-ray diffraction, Fourier-transform infrared spectroscopy and thermogravimetric analysis. The matrices are found to be reasonably stable to acid treatment at pH 4.5 for periods of up to 72 h, with anion exchange taking place. Results indicate that total exchange of interlayer carbonate for chloride, nitrate and vanadate may be accomplished. The thermal properties of the materials have been studied: they demonstrate interesting differences in thermal behaviour compared with hydrotalcite.