Template-induced synthesis of hierarchical SiO₂ at γ-AlOOH spheres and their application in Cr(VI) removal

Hierarchical structured SiO₂at γ-AlOOH spheres were fabricated in one step by using silica colloidal spheres as a template. Scanning electron microscopy and transmission electron microscopy investigation showed that the shell is composed of large amounts of nanoscale γ-AlOOH lamellas. The growth mechanism was proposed as silica template-induced heterogeneous deposition of γ-AlOOH lamellas. The adsorption properties of hierarchical SiO₂at γ-AlOOH spheres annealed at different temperatures were investigated through the removal test of Cr(VI) ions in model wastewater, and the nanostructures annealed at 400 °C showed good adsorption capability of Cr(VI) ions.