Monodispersed hierarchical aluminum/iron oxides composites micro/nanoflowers for efficient removal of As(V) and Cr(VI) ions from water

Many nanomaterials have been widely reported for removal of toxic inorganic metal ions. However, some nanoscale adsorbents are subject to serious aggregation. For example, it is very difficult to directly synthesize the monodispersed Fe(OH)3 nanomaterials. Here, through using the monodispersed hierarchical γ-Al2O3 nanoflowers as adsorbent supports, the Fe(OH)3 colloid nanoparticles have been well deposited onto the surfaces of the hierarchical γ-Al2O3 nanostructures to form γ-Al2O3/Fe(OH)3 composites with hierarchical structures via an electrostatic attraction without forming large aggregates. The γ-Al2O3/Fe(OH)3 composites with hierarchical structures have high specific surface areas and large pore volumes, which are used as adsorbents to remove anion species of As(V) and Cr(VI) from aqueous solution. The maximum capacities of the monodispersed γ-Al2O3/Fe(OH)3 composites with hierarchical structures for As(V) and Cr(VI) are determined at 61.99 mg g−1 and 24.13 mg g−1, respectively, which are higher than those of the other metal oxide nanostructures reported. In addition, the adsorption rates of As(V) and Cr(VI) onto the monodispersed γ-Al2O3/Fe(OH)3 composites with hierarchical structures are rather fast. The γ-Al2O3/Fe(OH)3 hierarchical micro/nanoflower structures show high adsorption capacity for removing anion species of As(V) and Cr(VI), demonstrating a promising potential in environmental remediation. The γ-Al2O3/Fe(OH)3 composites with hierarchical structures have been prepared for the first time, which show high specific surface areas and large pore volumes. The adsorption capacities of the monodispersed γ-Al2O3/Fe(OH)3 composites for As(V) and Cr(VI) in this study are higher than those of the other metal oxide nanostructures reported to date. [Display omitted] •Monodispersed hierarchical γ-Al2O3/Fe(OH)3 composites are prepared.•The design of the composites avoids nanoparticles aggregation.•The composites have high specific surface areas and large pore volumes.•The adsorption capacities of the composites for As(V) and Cr(VI) are high.