Abstract: Attempts had been made to synthesize Al2O3-2SiO2 nanopowders by sol-gel method with tetraethoxysilane (TEOS) and aluminum nitrate (ANN) as the starting materials. DTS, TEM, SEM and BET were employed to study the effects of process parameters on the size, specific surface area and structure (morphology) of powders. The alkali-activation reactivity of the powders was tested for manufacturing geopolymers and their hydrothermal reactions were performed for fabricating zeolites. The results show that the optimum process parameters and drying method for preparing Al2O3-2SiO2 nanopowders are as follows: the molar ratio of water and ethanol to TEOS are 0︰1 and 12︰1 respectively at synthetic temperature of 50 °C and the drying method is azeotropic distillation with microwave drying. The average particle diameters of the powders were about 70 nm and the largest BET specific surface area was up to 669 m2•g?1. The compressive strength of the geopolymer and the calcium exchange capacity (by CaCO3) of NaA zeolite prepared with the powders reached to 29 MPa and 366 mg•g?1 respectively.

Key words: parameter optimization, Al₂O₃-2SiO₂ nanopowder, sol-gel, geopolymer, zeolite

摘要： Attempts had been made to synthesize Al2O3-2SiO2 nanopowders by sol-gel method with tetraethoxysilane (TEOS) and aluminum nitrate (ANN) as the starting materials. DTS, TEM, SEM and BET were employed to study the effects of process parameters on the size, specific surface area and structure (morphology) of powders. The alkali-activation reactivity of the powders was tested for manufacturing geopolymers and their hydrothermal reactions were performed for fabricating zeolites. The results show that the optimum process parameters and drying method for preparing Al2O3-2SiO2 nanopowders are as follows: the molar ratio of water and ethanol to TEOS are 0︰1 and 12︰1 respectively at synthetic temperature of 50 °C and the drying method is azeotropic distillation with microwave drying. The average particle diameters of the powders were about 70 nm and the largest BET specific surface area was up to 669 m2•g?1. The compressive strength of the geopolymer and the calcium exchange capacity (by CaCO3) of NaA zeolite prepared with the powders reached to 29 MPa and 366 mg•g?1 respectively.

关键词: parameter optimization, Al₂O₃-2SiO₂ nanopowder, sol-gel, geopolymer, zeolite