中文摘要：

采用真空冷冻干燥技术结合反相微乳液法,于环己烷/聚乙二醇辛基苯基醚（曲拉通X-100）-十六烷基三甲基溴化铵（CTAB）/正丁醇/水溶液体系中,合成了纳米Al2O3粉体.采用扫描电子显微镜（SEM）、透射电子显微镜（TEM）、X射线衍射（XRD）及比表面积与孔隙度分析仪对产物的形貌、结构、比表面积、孔容与孔径进行了表征.经过煅烧,该纳米Al2O3比表面积约550.0m2·g-1（随反应参数不同而变化）,属γ-Al2O3晶型,粒径均匀,颗粒直径小于10.0nm.考察了不同的干燥方式（电热鼓风干燥、普通真空干燥、真空冷冻干燥）以及真空冷冻干燥过程中主要参数对产物比表面积、孔容、平均孔径等物理性质的影响.结果表明,采用真空冷冻干燥法制备的纳米Al2O3的比表面积和孔容远高于采用另外两种干燥方式制备的纳米Al2O3.采用真空冷冻干燥法制备纳米Al2O3时,降温速率、预冻时间、冻干时间等参数对最终制备的产物比表面积与孔结构有显著影响.

英文摘要：

Nano-alumina powders were prepared by vacuum freeze drying combined with reverse microemulsion method.The reverse microemulsion system consisted of cyclohexane/polyethylene glycol octylphenyl ether （Triton X100）-hexadecyl trimethyl ammonium bromide （CTAB）/n-butylalcohol/water.The morphology,structure,specific surface area,pore volume,and pore size of the alumina nanoparticles were characterized by scanning electron microscopy （SEM）,transmission electron microscopy （TEM）,X-ray diffraction （XRD）,and specific surface area analysis.The specific surface area of the alumina nanoparticles was about 550.0 m2·g-1 （changed with different reaction parameters） and the crystal structure was γ-Al2O3.The particle size was very uniform and smaller than 10.0 nm.The influence of different drying methods （normal hot-gas drying,normal vacuum drying,vacuum freeze drying） and the main parameters of vacuum freeze drying on the physical properties of the product were studied.Results showed that the nano-alumina powders obtained by vacuum freeze drying had much higher specific surface area and pore volume than that obtained by the two other drying methods.The specific surface area and pore structure of the nano-alumina were affected by the freezing rate,pre-freezing time,and drying time in the vacuum freeze drying process.