通过晶种导向法在无模板剂硅铝凝胶体系中合成SiAl-ITQ-58 8800字 知网 5%

通过晶种导向法在无模板剂硅铝凝胶体系中合成 Si/Al-ITQ-58【摘 要】沸石分子筛作为一种高效催化剂，在工业生产中有着重要作用。传统方法合成分子筛需要用到会对环境造成污染的有机结构导向剂，因此，使用晶种导向法在无模板剂条件下合成分子筛是研究的热点之一。目前报道合成的 ITQ-58 是硅硼分子筛，酸性低，催化性能不够好，因此希望能够使用晶种导向法合成出硅铝分子筛 ITQ-58。在本文中，我们考察了不同硅源、铝源和碱源，以及不同铝硅比、碱硅比和水硅比对通过晶种导向法在无模板剂硅铝凝胶体系中合成 Si/Al-ITQ-58 的影响。结果表明，以白炭黑作为硅源、NaAlO2 作为铝源和 NaOH 作为碱源，原料配比 n(SiO2) : n(NaAlO2) : n(NaOH) : n(H2O) =1: 0.020: 0.55: 20 ， 晶 化 时 间 10 天 ， 晶 化 时 间 125℃ 时 为 最 佳 条 件 。 采 用XRD、SEM、ICP 和热重分析仪对样品进行了表征，结果表明，所得产物仍含少量无定形，需要进一步晶化，产物与 ITQ-58 结构相似，硅铝比为 15.06。【关键词】晶种导向法；Si/Al-ITQ-58；硅源；铝源【ABSTRACT】As a high-efficiency catalyst, zeolite plays an important role in industrial production. Traditional methods for synthesizing zeolites require the use of organic structure directing agents that would cause environmental pollution. Therefore, the use of seed-directed methods to synthesize zeolites without template is one of the research hotspots. It is reported that the synthesized ITQ-58 is a kind of silica-boron zeolite with low acidity and insufficient catalytic performance. Therefore, it is desirable to synthesize Si/Al-ITQ-58 by eed-directed method.In this work, seed-directed methods without template were used to synthesize zeolites. And the influences of different silicon sources, different aluminum sources and different alkali sources, as well as different ratios of aluminum to silicon, alkali to silicon and water to silicon were investigated. The results show that the optimum conditions are silica as the silicon sou...