低成本大比表面积γ-Al_2O_3的制备

Economical synthesis of γ-Al_2O_3 with large surface area

以廉价无机铝盐硫酸铝为原料,氨水为沉淀剂,十二烷基硫酸钠为添加剂,采用简单沉淀法制备得到较大比表面积γ-Al_2O_3。通过N_2低温物理吸附-脱附、X射线衍射、红外光谱、热重、元素分析、扫描及透射电镜等,研究制备过程中沉淀温度、溶液pH值和添加剂用量对产物γ-Al_2O_3及其前驱体的晶相结构、形貌织构等性质的影响。结果表明,在沉淀温度75℃、硫酸铝浓度0. 25 mol·L^(-1)、溶液pH=9. 0、老化时间12 h和n(十二烷基硫酸钠)∶n[Al_2(SO_4)_3]=0. 375∶1条件下,所得前驱体(拟薄水铝石)经600℃焙烧后,可获得大比表面积(416. 65 m^2·g^(-1))γ-Al_2O_3,并且样品中因十二烷基硫酸钠添加,引入的S及Na等杂质含量极少。

Large surface area γ-Al2O3 was synthesized via simple precipitation method using inexpensive aluminum sulfate as aluminum source,ammonium hydroxide as precipitating agent and sodium dodecyl sulfate( SDS) as additive. The effects of precipitation temperature,solution p H value,and SDS adding amount on phase structure and textural property of prepared γ-Al2O3 samples and their precursors were investigated by characterization techniques including cryogenic N2 physical adsorption-desorption,X-ray diffraction,infrared spectroscopy,thermal analysis,elemental analysis,scanning and transmission electronic microscopy. The results showed that γ-Al2O3 with large surface area( 416. 65 m2·g-1) was synthesized after calcination at 600 ℃ of pseudo boehmite precursor which was prepared at precipitation temperature of 75 ℃,aluminum sulfate concentration of 0. 25 mol·L-1,pH value of 9. 0,aging time of 12 h,and n( sodium dodecyl sulfate) ∶ n( aluminum sulfate) = 0. 375 ∶ 1. Moreover,there was little impurities such as S and Na coming from SDS existing on the γ-Al2O3 sample.