Intracrystalline Diffusion in Mesoporous Zeolites
Intracrystalline Diffusion in Mesoporous Zeolites
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DOI：
10.1002/cphc.201200048
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发表时间：
2012-04-23
期刊：
影响因子：
2.9
通讯作者：
Ryoo, Ryong
中科院分区：
文献类型：
--
作者：
Mehlhorn, Dirk;Valiullin, Rustem;Ryoo, Ryong
特别合成的超大晶粒沸石LTA与有意添加的介孔用于在层次的纳米多孔材料中的客体扩散的脉冲场梯度NMR技术的深入研究。使用丙烷作为客体分子，晶内传质被证明是充分描述由一个单一的有效扩散率导致在两个（微米和介孔）孔隙空间的扩散率的加权平均。气体动力学顺序的扩散率的数量级估计是令人满意的协议与实验数据，并因此显示出提供一个简单的手段，用于预测和量化的好处，分层结构的纳米多孔材料相比，他们的纯微孔等效。
Specially synthesized extra-large crystallites of zeolite LTA with intentionally added mesoporosity are used for an in-depth study of guest diffusion in hierarchical nanoporous materials by the pulsed field gradient NMR technique. Using propane as a guest molecule, intracrystalline mass transfer is demonstrated to be adequately described by a single effective diffusivity resulting from the weighted average of the diffusivities in the two (micro- and meso-) pore spaces. Gas-kinetic order-of-magnitude estimates of the diffusivities are in satisfactory agreement with the experimental data and are thus shown to provide a straightforward means for predicting and quantifying the benefit of hierarchically structured nanoporous materials in comparison with their purely microporous equivalent.