大孔体积、超高比表面积γ-Al_2O_3的制备与表征

Preparation and Characterization on Superhigh Specific Surface Area of Nanometer Alumina

以工业级硫酸铝和碳酸氢铵为原料,利用超声波分散技术和化学沉淀相结合的方法制备了拟薄水铝石,拟薄水铝石经600℃高温煅烧,得到了大孔体积、超高比表面积的纳米γ-Al_2O_3粉体;考察了制备过程中发泡剂吐温60及干燥方式对γ—Al_2O_3的结构、形貌及性能的影响,并采用傅里叶变换红外光谱、X 射线衍射、比表面积测定、扫描电子显微镜等于段对γ-Al_2O_3进行了表征。结果表明,在超声场中,以聚乙二醇为分散剂,用发泡剂吐温60分散干燥、煅烧的方式制备的纳米纤维状γ-Al_2O_3的性能最好,γ-Al_2O_3的粒径为25～100 nm,长150-500 nm,平均孔径12.691～12.699 nm,孔体积1.383～2.089 mL/g,比表面积319.598～500.899 m^2/g。

Pseudoboehmite （PB）was prepared from Al2 （SO4 ）3 · 12H2O and NH4HCO3 by precipitation with the aid of ultrasonic dispersion and polyethylene glycol as dispersing agent. Addition of anti-agglomeration agent （Tween 60） to the obtained PB before drying, different addition amounts and different drying methods of PB were studied. After drying, PB was calcined at 600 ℃ for 4 h to achieve the target nano γ-Al2O3 which was characterized by means of FTIR, XRD, BET and SEM. The addition of appropriate amount of anti-agglomerization agent to PB before drying and drying of PB by means of microwave are preferred measure in producing nano γ-Al2O3with superhigh specific surface area, large pore volume and more even pore diameter. The end product nano γ-Al2O3 are nano-fiber-like particles with average diameter of 25 - 100 nm, average length of 150 - 500 nm, average pore diameter of 12. 691 - 12. 699 nm, pore volume of 1. 383 -2. 089 mL/g, and specific surface area of 319. 598 -500. 899 m^2/g.