导向剂法合成β沸石的晶化机制研究

Studies on the Crystallization Mechanism of β Zeolite Synthesized with Nucleation Gel

采用导向剂法合成了β沸石 .在导向剂中存在β沸石微晶核 ,晶化过程中β沸石只能在一个较窄的硅铝比范围内形成 ;模板剂 TEAOH仅存在于 β沸石微晶核中 .在 β沸石合成过程中 ,水合钠离子不仅起着平衡沸石骨架负电荷的作用 ,并且在 β沸石的晶体生长过程中起到一定程度的结构导向作用 .

Zeolite β was synthesized with a nucleation gel. The IR spectroscopic characterizations confirm the existence of the microcrystal nuclei in the nucleation gel. Chemical analysis of solid and liquid phases demonstrates that zeolite β can grow within a relatively narrow n(Si)/n(Al) ratio range. TGA analysis reveals that TEAOH only exists in the microcrystal nuclei formed in the nucleation gel. It was also found that the negative charges of the zeolite framework are actually balanced by the hydrated Na+ ions, which may direct the growth of zeolite β during the crystallization process.