《HMS介孔分子筛的合成和表征》-毕业论文.doc

PAGE 摘　　要 本文以十八胺（ODA）作为模板剂、正硅酸乙酯（TEOS）作为硅源、水作为溶剂、乙醇和1, 3, 5-三甲苯（TMB）作为共溶剂，采用水热合成法合成了HMS介孔分子筛，并采用XRD、低温N2吸附-脱附和HRTEM对产物的结构进行了表征。 HRTEM照片显示所合成的分子筛具有HMS介孔分子筛的特征形貌，即接近六方的短程有序孔道结构，孔道之间相互连通。XRD分析结果也表明：HMS分子筛在小角区域2θ≈2o处存在介孔分子筛的特征衍射峰，呈现出很好的六方晶型，具有规整有序的孔道结构。此外，还采用N2吸附-脱附方法详细测定了不同温度条件下HMS的孔结构参数。 本文系统研究了模板剂的类型及浓度、合成温度、反应时间和亲/疏水共溶剂的加入对合成HMS产物结构性质的影响，进而确定最优的合成条件。结果表明：模板剂ODA的浓度过高或过低都不利于HMS介观结构的形成，当n(ODA)/n(TEOS)=0.27时，HMS的结构性质较为理想；反应温度在45-60℃是合成HMS的最佳温度范围；在该条件下HMS的合成中，存在一个最佳反应时间，这个时间稍大于14h；乙醇在HMS的合成中是必需的，但乙醇含量的增加对产物HMS的骨架结构不利；TMB是一种优良的扩孔剂，当n(TMB)/n(ODA)=1.0时，实验表明其扩孔效果较佳。 关键词：HMS；介孔分子筛；合成；表征 ABSTRACT In this thesis, octadecylamine (ODA) as the structure-directing surfactant, tetraethyl orthosilicate (TEOS) as silicate source, ethanol and 1, 3, 5-trimethylbenzene (TMB) as a cosolvent were used to synthesize mesoporous HMS molecular sieves through hydrothermal method. XRD, N2 adsorption-desorption at low temperature and HRTEM were used to characterize the structure of the HMS samples. HRTEM images showed that the synthesis sample exhibited the properties of mesoporous HMS molecular sieves in that it has approximately ordered hexagon short-range pore framework structure with pore-pore transfixion. The same conclusions were obtained through the results of XRD with a characteristic diffraction peak of mesoporous molecular sieves at 2θ ≈ 2o. In addition, pore structure parameters of HMS assembled under different conditions were determined by N2 adsorption-desorption particularly. In this thesis, the effect of factors such as concentration of the structure-directing surfactant, synthesis temperature and reaction time, the existence of hydrophilic or hydrophobic cosolvents on the framework structure of the as-made mesoporous HMS molecular sieves was systematically studied to fix on an optimum synthesis condition. The results indicated that the mesoporous structure of synthesis HMS was ideal when n (ODA)/n (TEOS) =0.27, too high or too low concentration of the structure-directing octad