KOH/NaOH两种碱性体系下合成纳米片层分子筛

Synthesis of Nanosheets Zeolite in Two Alkaline Systems of KOH/NaOH

以小分子阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)为结构导向剂,在KOH和NaOH 2种碱性体系下水热合成纳米片层分子筛,并分析K^(+)、Na^(+)和Silicalite-1晶种溶胶对合成样品的物相和形貌的影响。结果表明:以KOH为碱源,在添加Silicalite-1晶种溶胶的条件下,水热晶化96 h即可合成高结晶度、纳米薄片沿b轴方向有序堆积多层和随机堆积单层的混合形貌ZSM-5分子筛;以NaOH为碱源,在不添加Silicalite-1晶种溶胶的条件下,水热晶化48 h即可合成高结晶度、由纳米薄片和纳米棒紧密堆积而成的纺锤状聚集体形貌MOR分子筛。研究结果可为进一步优化合成MOR和ZSM-5分子筛纳米片提供思路。

Nanosheets zeolite was synthesized using small cationic surfactant cetyltrimethylammonium bromide(CTAB)as a structure-directing agent under two basic systems of KOH/NaOH.The effects of alkali metal ions(K^(+),Na^(+))and Silicalite-1 seed sol on the phase and morphology of synthesized samples were analyzed.The results show that ZSM-5 zeolite with high crystallinity may be hydrothermal crystallized for 96 hours under the use of KOH as the alkali source and the addition of Silicalite-1 seed sol,and possesses a mixed morphology of the multilamellar and unilamellar structure constituted of orderly stacked nanosheets along the b-axis and randomly stacked nanosheets,respectively.Nevertheless,MOR zeolite with high crystallinity and fusiform aggregate morphology,which consists of densely packed nanosheets and nanorods,can be synthesized by hydrothermal crystallization for 48 hours without the need of Silicalite-1 seed sol when using NaOH as the alkali source.The findings can offer suggestions for further optimizing the production of MOR and ZSM-5 nanosheets.