Abstract:

Ge-ZSM-5 membranes were prepared by in-situ hydrothermal crystallization method on two kinds of α-Al₂O₃ substrates. The synthesized membranes were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The effect of the content of water in the synthesis solution on the microstructure of the membranes and the pervaporation separation performance of the membrane were investigated. The results showed that there were molecular sieve crystals at the top of the membranes when the water content in the synthesis solution was smaller. With the increase of water content, the crystals on the surface of the membranes were gradually covered by amorphous material, and finally amorphous material could form a continuous layer with the best separation performance. When the water content was bigger, the membranes were discontinuous. With the increase of water content in the synthesis solution, the content of aluminum in the membranes increased, the content of germanium decreased and the separation performance of the membranes was gradually optimized. On the substrate which was easier to melt aluminum, the content of aluminum in the membranes was higher and the separation performance of the membranes was better. At 30℃, the water permeation flux of 1%—35% ethylene glycol solution ranged from 35.7—116.7g/(m²·h) and the separation factor ranged from 1138.5 to 46.5 on the Ge-ZSM-5 membrane, which had the best separation performance and the membrane had the potential application for dehydration of low concentration ethylene glycol solution.

Key words: zeolite membrane, pervaporation, ethylene glycol solution, dehydration

摘要：

采用原位水热晶化法在两种氧化铝载体上制备Ge-ZSM-5膜。利用扫描电子显微镜（SEM）、能量色散光谱（EDS）及X射线衍射（XRD）对膜进行表征。考察合成液中水含量对膜的微结构及膜对乙二醇溶液渗透汽化分离性能的影响。结果表明，水含量较少时，膜表面为分子筛晶体；增加水含量，膜表面晶体逐渐被无定形物质覆盖，最终无定形物质可形成连续层，此时膜的分离性能最好；水含量较高时，膜层不连续。合成液中水含量增加，膜中铝含量升高，而锗含量降低，膜的分离性能逐渐优化。在更易于溶出铝元素的载体上，膜中铝元素含量较高，分离性能更好。在分离性能最好的Ge-ZSM-5膜上，30℃时，对于水质量分数为1%~35%的乙二醇溶液，其水渗透通量为35.7~116.7g/(m²·h)，分离因子为1138.5~46.5，该膜对高浓度乙二醇溶液脱水具有应用潜力。

关键词: 分子筛膜, 渗透汽化, 乙二醇溶液, 脱水