Amorphous nanostructured composites Al2O3:nC with enhanced sorption affinity to La(III), Ce(III), U(VI) ions in aqueous solution

Abstract

• Al 2 O 3 :nC composite was prepared by the precursor method. • Effect of microstructure on the sorption properties of Al 2 O 3 :nC has been studied. • Al 2 O 3 :nC has a much larger sorption affinity to (La, Ce, U) ions compared to Al 2 O 3 powders. The nanostructured Al 2 O 3 :nC composites with enhanced chemical activity and higher solubility of oxide in acids have been synthesized. For the synthesis, an organometallic precursor, produced by thermal treatment of a mixture of Al(NO 3 ) 3 ·9H 2 O with ethylene glycol, was heated in helium atmosphere at 700–1100 °C. X-ray powder diffraction, selected-area electron diffraction and transmission electron microscopy revealed the formation of a homogeneous amorphous mass with indistinguishable boundaries between the oxide and carbon components at 700–1000 °C, while annealing at 1100 °C provoked the crystallization of γ-Al 2 O 3 nanoparticles, forming a clear Al 2 O 3 /carbon interface. This specific microstructure provides a high sorption affinity of the composite for La (III), Ce (III), U (VI) ions in aqueous solutions, which is significantly higher than that of microcrystalline aluminum oxides.