QUAN Tingting ¹ , GUO Xiaorui ¹ , XIE Tianyi ¹ , LIN Huixing ² , MENG Fancheng ^{1, 2}
(1. School of Materials Science and Engineering, Chongqing University of Technology, Chongqing 400054, China; 2. Key Laboratory
of Inorganic Functional Materials and Devices, Chinese Academy of Sciences, Shanghai 200050, China)

Abstract: The hierarchical γ-AlOOH was prepared by a facile template-free hydrothermal method, using aluminum nitrate (Al(NO₃)₃·9H₂O)as aluminum source and sodium phosphate dibasic (Na₂HPO₄) as precipitator. The effects of concentration of Na2HPO4 and Al(NO₃)₃·9H₂O on the phase, morphology and adsorption property of the synthesized products were studied. The obtained sample was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and N₂ adsorption/ desorption technique. The possible formation mechanism of hierarchical γ-AlOOH was discussed. The experimental results show that when the concentrations of Al(NO₃)₃ and Na₂HPO₄ were 0.05 mol/L and 0.0025 mol/L, the hierarchical γ-AlOOH was synthesized after reaction at 190 ℃ for 24 h. The obtained sample with an average length of 2.0-3.0 μm and a width of 1.0-1.4 μm was assembled by one-dimensional fiber. The hierarchical γ-AlOOH showed the superior removal efficiency for Congo red with the maximum adsorption capacity of 98.6 mg/g. And it exhibited a BET surface area of 151.20 m²/g and an average pore size of 3.5 nm.

Key words: γ-AlOOH; bundle-like; hydrothermal method; adsorption