【作者】 张波；

【导师】 张宝泉；

【作者基本信息】 天津大学 ， 化学工程， 2013， 硕士

【摘要】 本文系统研究了Silicalite-1与Fe-silicalite-1分子筛膜的合成、表征及其在渗透蒸发中应用。选择了400nm大小的Silicalite-1分子筛晶体作为晶种，采用旋涂的方式在α-Al2O3载体表面制备了一层随机取向，厚度为1.5μm的晶种层。然后在150℃下采用二次生长法生长两次，合成出连续致密的（h0l）取向、厚度为5μm的Silicalite-1分子筛膜和连续致密的（h0l）和a-轴取向、厚度为4.5μm的Fe-silicalite-1分子筛膜。红外和紫外表征结果表明Fe以骨架铁的形式存在于Fe-silicalite-1分子筛膜中，而且合成液中Fe3+能促进分子筛之间的交联，使合成的Fe-silicalite-1分子筛膜比Silicalite-1分子筛膜更为连续致密。高温煅烧能够完全脱除Silicalite-1和Fe-silicalite-1分子筛膜中模板剂，但也会使它们产生较大缺陷，从而使二者在乙醇/水混合液的渗透蒸发中基本上丧失分离性能，表现为极高的通量和极低的分离因子。低温煅烧不能脱除Silicalite-1分子筛膜中的模板剂，但由于Fe引入骨架，使膜催化活性增加，该法能够有效脱除Fe-silicalite-1分子筛膜中的模板剂。而且模板剂脱除后，膜最大孔径不超过1.1nm，其中大部分孔径分布在0.4~0.85nm之间，有效地避免缺陷的产生。低温煅烧脱除模板剂后，Fe-silicalite-1分子筛膜具有高于文献报道的通量，313K、323K和333K时，其值分别高达1.54、2.05和2.64kg/(m2·h)。但是，由于氧化铝载体铝析出导致的膜硅铝比偏低，使得Fe-silicalite-1分子筛膜表面接触角仅为69.7°，表现为亲水特性，从而使最终的分离因子低于文献报道的数据，仅在18~20之间。通量和分离因子都随着操作温度的升高而增大，但通量的增幅较大，而分离因子的增幅较小。而且，在同一温度下，低温煅烧脱除模板剂后的不同Fe-silicalite-1分子筛膜，其渗透蒸发分离效果重复性很高。更多还原

【Abstract】 In this paper, we systematically investigated the synthesis and characterization ofSilicalite-1and Fe-silicalite-1membranes and their applications in pervaporation.Silicalite-1crystals with a size of400nm were chosen as the seeds to prepare the seedlayer, and the as-prepared seed layer was randomly oriented, with a thickness of1.5μm. Then, a well-designed two-step seeded growth method was used to synthesizeSilicalite-1and Fe-silicalite-1membranes on porous α-Al2O3substrate. A5μm thick,(h0l) oriented silicalite-1membrane and a4.5μm thick,(h0l) and a-orientedFe-silicalite-1membrane were synthesized after the second-time seeded growth at150℃, and these membranes were continues and dense. For Fe-silicalite-1membrane,the results of the FT-IR, UV-vis spectra indicated the iron was introduced into thezeolite framework. And the existence of Fe3+in synthesis solution could accelerate theintergrowth of zeolite crystals, leading to the as-prepared Fe-silicalite-1membranewas much more continues and denser than the as-synthesized silicalite-1membrane.High temperature calcination could absolutely remove the templates in the silicalite-1and Fe-silicalite-1membranes, but cracks formed at the same time, which conducethese membranes almost lost separating effect, and PV results of these membraneswere that the flux was very high, but the separation factor was very low. Lowtemperature calcination couldn’t remove the template of silicalite-1membrane. While,owing to the introduction of Fe into the zeolite framework, the catalytic activity of theFe-silicalite-1membrane was increased. So low temperature calcination couldeffectively remove the template of Fe-silicalite-1membrane, and the membrane wascrack-free, because the size of the biggest pore was under1.1nm, and the size of mostpores was between0.45nm and0.85nm. After the template was removed by the lowtemperature calcination method, the Fe-silicalite-1membranes showed a flux of1.54,2.05and2.64kg/(m2·h) at313,323and333K, respectively, which were higher thanliterature data. However, due to the aluminum leaching from the α-Al2O3substrate,the Si/Al ratio of the membrane was very low, and the membrane was hydrophilic,with a average contact angle of69.7degree, so the separation factor was very low,only ranged from18to20. Both the flux and separation factor increased with theincreasing PV temperature for the5wt.%ethanol feed solution. However, the increase of separation factor was lower than that of flux. When low temperaturecalcination method was used to remove the template, the Fe-silicalite-1membranesshowed a very high PV separation repeatability at the same PV temperature.更多还原