Synthesis of zeolite L membranes with sub-micron to micron thicknesses
Synthesis of zeolite L membranes with sub-micron to micron thicknesses
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DOI：
10.1016/j.micromeso.2008.02.012
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发表时间：
2008-11
影响因子：
5.2
通讯作者：
Jeremy White;P. Dutta;K. Shqau;H. Verweij
中科院分区：
文献类型：
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作者：
Jeremy White;P. Dutta;K. Shqau;H. Verweij
以L型沸石为例，研究了在亚微米至微米范围内具有可控厚度的沸石膜的生长。结果表明，通过控制沸石固体负载的浓度和悬浮液粘度，浸涂提供了一种制备受控厚度的沸石晶种层的方法。以粒径分布为0.5 ~ 2μm的L型沸石晶体为晶种，制备了2-7μm厚的膜。通过选择二次生长介质的组成以及时间和温度，晶体生长主要沿这些微米加厚度膜中的xy平面沿着发生，最终厚度类似于最初沉积的晶种层。对于亚微米尺寸的膜的合成，使用20至60 nm的晶种，并且观察到沿着z轴的生长。发现最佳的二次生长条件发生在60小时的生长时间（对于亚微米膜为40小时），使用110°C的温度，溶液组成为10 K2 O：1Al 2 O3：20 SiO2：2000 H2O。膜的特征在于通过电子显微镜和单一气体渗透研究，提供膜致密化的确认。
The growth of zeolite membranes with controlled thicknesses in the sub-micron to micron region is examined, using zeolite L as the example. It was demonstrated that by controlling the concentration of the zeolite solid load and suspension viscosity, dip-coating provided a method to prepare zeolite seed layers of controlled thicknesses. Disk-shaped zeolite L crystals, with size distribution of 0.5–2μm in diameter, were used as seed crystals for the growth of 2–7μm thick membranes. By choosing the composition of the secondary growth medium, as well as time and temperature, crystal growth primarily occurred along the xy-plane in these micron plus-thickness membranes, with eventual thickness similar to the originally deposited seed layer. For the synthesis of sub-micron-sized membranes, seed crystals from 20 to 60nm were used and growth was observed along the z-axis. The optimum secondary growth conditions was found to occur at 60h of growth time (40h for sub-micron membranes) using a temperature of 110°C with a solution composition of 10K2O:1Al2O3:20SiO2:2000H2O. Membranes were characterized by electron microscopy and single gas permeation studies, providing confirmation of membrane densification.