沉淀法结合超临界CO_2干燥制备纳米γ-Al_2O_3

Chemical Precipitation-Supercritical CO_2 Drying for Preparing Nano γ-Al_2O_3

纳米γ-Al2O3具备多孔性、高比表面积、良好的吸附性、热稳定性和表面酸性。用作吸附剂和催化剂（及其载体）。是催化剂载体领域应用最为广泛的品种。制备纳米氧化铝的方法有很多，大致可分为固相法、液相法、气相法等。沉淀法是液相法中被广泛应用的一种．但是沉淀法生产过程中易形成严重的硬团聚。团聚的原因是多种多样的．其中一个主要原因是．凝胶颗粒之间液态水分子存在．湿凝胶中含有大量的水分．蒸发之初没有产生气液界面．不会产生毛细作用．随着液面的不断蒸发．

The nano γ-Al2O3 was prepared by chemical precipitation combined with supercritieal CO2 drying. The nano γ-Al2O3 was characterized by TG-DTA analysis, XRD diffraction, N2 physical adsorption-desorption testing, SEM and TEM analysis. Compared with the sample prepared by general drying, smaller particle size and greater surface area were obtained. The supercritical CO2drying was more effective in reducing aggregation.