In order to improve the activity and eliminate some impurities, pretreatment was used before hydrothermal synthesis. The fly ash was mixed with an aqueous NaOH solution, the alkali melted fly ash was also adopted, whi...In order to improve the activity and eliminate some impurities, pretreatment was used before hydrothermal synthesis. The fly ash was mixed with an aqueous NaOH solution, the alkali melted fly ash was also adopted, which is hydrothermally treated at about 104 ℃, and the liquid/solid ratio was controlled at 6：1. In order to control Si/Al molar ratio, SiO2 or Al2O3 powers were added to the fly ash. The results of XRD and SEM show that the alkali melted can activate fly ash and eliminate its quartz and mullite, along with the improvement of Si/Al molar ratio and alkalinity. In addition, zeolite Na-A changes into sodalite gradually, and nepheline is the synthesized intermediate product. Those results were discussed on the basis of a formation mechanism of zeolite from fly ash.展开更多
采用磁控溅射工艺在PET衬底上依次沉积了Al_2O_3和SiO_2薄膜,制备出SiO_2/Al_2O_3/PET复合膜。利用扫描电镜和透湿仪对复合膜的表面形貌和透湿性能进行表征。研究了制备Al_2O_3膜层的射频功率、氩气流量、本底真空度和溅射时间4个参数...采用磁控溅射工艺在PET衬底上依次沉积了Al_2O_3和SiO_2薄膜,制备出SiO_2/Al_2O_3/PET复合膜。利用扫描电镜和透湿仪对复合膜的表面形貌和透湿性能进行表征。研究了制备Al_2O_3膜层的射频功率、氩气流量、本底真空度和溅射时间4个参数对复合膜透湿率的影响。结果表明:复合膜的透湿率随着本底真空度的升高而减小,随着射频功率、氩气流量和溅射时间的增加均呈现先减小后增大的变化趋势;4个制备参数对复合膜透湿率的影响程度由大到小依次是本底真空度、氩气流量、射频功率、溅射时间;4个制备参数的较优组合为本地真空度0.5×10^(-3)Pa,射频功率300 W,溅射时间6 min,氩气流量70 m L·min^(-1)。展开更多
基金Supported by the Henan Outstanding Youth Science Fund (0612002400)
文摘In order to improve the activity and eliminate some impurities, pretreatment was used before hydrothermal synthesis. The fly ash was mixed with an aqueous NaOH solution, the alkali melted fly ash was also adopted, which is hydrothermally treated at about 104 ℃, and the liquid/solid ratio was controlled at 6：1. In order to control Si/Al molar ratio, SiO2 or Al2O3 powers were added to the fly ash. The results of XRD and SEM show that the alkali melted can activate fly ash and eliminate its quartz and mullite, along with the improvement of Si/Al molar ratio and alkalinity. In addition, zeolite Na-A changes into sodalite gradually, and nepheline is the synthesized intermediate product. Those results were discussed on the basis of a formation mechanism of zeolite from fly ash.
文摘采用磁控溅射工艺在PET衬底上依次沉积了Al_2O_3和SiO_2薄膜,制备出SiO_2/Al_2O_3/PET复合膜。利用扫描电镜和透湿仪对复合膜的表面形貌和透湿性能进行表征。研究了制备Al_2O_3膜层的射频功率、氩气流量、本底真空度和溅射时间4个参数对复合膜透湿率的影响。结果表明:复合膜的透湿率随着本底真空度的升高而减小,随着射频功率、氩气流量和溅射时间的增加均呈现先减小后增大的变化趋势;4个制备参数对复合膜透湿率的影响程度由大到小依次是本底真空度、氩气流量、射频功率、溅射时间;4个制备参数的较优组合为本地真空度0.5×10^(-3)Pa,射频功率300 W,溅射时间6 min,氩气流量70 m L·min^(-1)。
文摘纳米ZSM-5分子筛由于其特殊的孔道和表面性质,显示出优异的吸附与催化性能,但粒径小于100 nm的ZSM-5分子筛极易发生团聚。以正硅酸乙酯为硅源、偏铝酸钠为铝源、四丙基氢氧化铵为模板剂,合成硅铝物质的量比分别为25、50、100、200和400的纳米ZSM-5分子筛。通过X射线衍射(XRD)、扫描电镜(SEM)、N_(2)物理吸附-脱附、^(27)Al固体核磁共振(^(27)Al MAS NMR)表征,结果表明,在硅铝物质的量比为25~400范围,均可合成粒径小于100 nm的ZSM-5分子筛。同时随着硅铝物质的量比增加,分子筛结晶度变强,分散性变好,比表面积和孔容增加,非骨架铝减少。
