Facile hydrothermal synthesis of hierarchically structured γ-AlOOH for fast Congo red removal

• Hierarchical γ-AlOOH was synthesized by a simple template-free hydrothermal method.
• The hierarchical morphology show a siamesed straw-sheaf shape.
• The hierarchical γ-AlOOH exhibits a large BET surface area (163m2/g).
• γ-AlOOH hierarchitectures showed excellent removal efficiency for Congo red.

Hierarchical γ-AlOOH with siamesed straw-sheaf morphology was synthesized by a simple template-free hydrothermal route. The obtained hierarchical γ-AlOOH structure was assembled by nanowire and exhibited large Brunauer–Emmett–Teller (BET) surface area of 163 m2/g and pore volume of 0.30 cm3/g. The adsorption efficiency of the samples with Congo red (CR) was studied by UV–vis spectroscopy. The sheaflike hierarchical γ-AlOOH shows an extremely high Congo red (CR) removal efficiency from waste water showing almost complete removal within 10 min. The maximal adsorption reaches 99 mg/g.