Self‐Assembled 3D Hierarchically Structured Gamma Alumina by Hydrothermal Method

Abstract

Self‐assembled γ‐Al2O3 with hierarchical structure was successfully obtained via thermolysis of γ‐boehmite (γ‐AlOOH) particles, which was hydrothermally derived from aluminum ammonium sulfate hydrate (NH4Al(SO4)2·12H2O), urea, poly‐glycol (PEG)‐2000, and deionized water. SEM observations indicate that the as‐synthesized γ‐AlOOH has hierarchical flower‐like structure, composing of needle‐like building blocks. After calcinations at 800°C, it converts to cubic γ‐Al2O3 with hierarchical structure retained by a topotactical process. N2 adsorption and desorption reveal that the obtained γ‐Al2O3 has a BET surface area of 101 m2/g with a narrow mesoporous size of about 13 nm and a broad macroporous‐size distributions of 200–500 nm, respectively. The as‐generated γ‐Al2O3 with hierarchical structure shows good capacities for removing Congo red from wastewater, indicating that 3D hierarchical structure has excellent adsorption ability.

Template‐Free Fabrication of Mesoporous Alumina Nanospheres Using Post‐Synthesis Water‐Ethanol Treatment of Monodispersed Aluminium Glycerate Nanospheres for Molybdenum Adsorption

“…The third weight loss step in the temperature region of 400–600 °C is correlated to the conversion of boehmite (AlOOH) into amorphous Al 2 O 3 via dehydration . The weight loss percentage corresponding to this conversion is 20.1%, which is close to the theoretical value of ≈15 wt%, according to the equation[17,21a]…”

“…Glycerol molecules self‐assembled into spherical quasi‐emulsions in 2‐propanol through strong intermolecular hydrogen bonding under solvothermal conditions, thereby promoting the growth of uniform nanospheres . There may also be a gradual solvent exchange and it is reasonable to assume that in the case of dispersed glycerol, the aluminium alkoxide solubilized within the glycerol droplets would react with glycerol to form aluminium glycerate nanospheres . As shown in Figure S1 (Supporting Information), when the amount of glycerol is low, nanospheres cannot be formed but instead only small nanoparticles are obtained.…”

Hollow Al2O3spheres prepared by a simple and tunable hydrothermal method

“…28 32 Glucose has been widely used as a template agent and organic fuel for the generalized synthesis of metal oxide hollow spheres by the hydrothermal technique. 28 32 Glucose has been widely used as a template agent and organic fuel for the generalized synthesis of metal oxide hollow spheres by the hydrothermal technique.…”

Surfactant directed synthesis of mesoporous alumina and α‐alumina single crystal

“…Here the adsorption property of the 600 °C calcined activated alumina is studied using Congo red as the dye. The adsorption of Congo dye is also studied for alumina with a range of shapes like nano fibers , nano fibers to nano rods , hierarchially structures 3D alumina and stalk like alumina .…”