【作者】 陈小霞；

【导师】 殷德宏； 杨建华；

【作者基本信息】 大连理工大学 ， 化学工程与技术， 2012， 硕士

【摘要】 有机物分离在石油化工、精细化工、医药工程等众多领域中是必不可缺的过程。传统分离工艺往往能耗高、效率低。渗透蒸发膜分离作为一种高效、节能、环保的技术被认为是将来替代传统分离工艺的潜在技术。工业应用中许多有机物精制过程发生在酸性条件下,如医药化工中乙醇、丙醇精制过程,酯类产晶的制备等。高度亲水性的NaA沸石膜是用于有机溶剂脱水过程理想的沸石膜,目前已实现工业化,然而其耐酸性极差。T型沸石膜是一种耐酸的亲水性沸石膜,将其用于有机溶剂脱水过程、尤其是酸性环境中有机物分离过程,表现出良好的渗透蒸发性能。因此T型沸石膜具有广阔的应用前景。然而,研究发现成熟的制备路线仍是目前T型沸石膜研究过程中亟待解决的问题。晶种法是指在载体表面预先引入一层晶种,再晶化成膜。优质的晶种层是晶种法制备高质量沸石膜的关键,因此涂晶技术也成了目前研究热点之一。微波合成法是近些年发展起来的一种新的沸石膜制备路线,能有效缩短合成时间,制备的膜薄而致密,从而有效提高分离性能。基于上述研究思路,本论文首先合成出不同尺寸的T型分子筛,用于修饰载体和作为晶种诱导成膜；然后详细研究了凝胶体系中传统水热合成、清液体系中微波合成等,以探索出成熟的T型沸石膜合成路线；还考察了在廉价大孔载体上采用有效涂晶方法制备出优质的晶种层和高性能的T型沸石膜。合成的T型沸石膜采用XRD、SEM等手段表征。主要研究成果如下：(1)采用无模板剂配方25Si02：A1203：6.5Na20：225K20：350H20,制备出5-6μm的T型分子筛：在含模板剂配方18.2Si02：A1203：4.2Na20：1.5K20：0.82TMAOH:212.7H20下考察了合成条件对分子筛形貌的影响,制备出不同尺寸的T型分子筛。(2)在凝胶体系中采用传统水热合成法制备T型沸石膜,考察了合成条件对膜的影响。在n(Na20+K20)/n(Si02)=0.35、n(H20)/n(Si02)=30、373K和30h条件下合成的T型沸石膜在348K下分离90wt.%乙醇/水,通量为1.67kg-m-2·h-1,分离系数是1115。(3)采用两步变温热浸渍法在廉价大孔载体管上引入高质量的晶种层。合成的T型沸石膜在348K下分离90wt.%乙醇/水,通量高达2.12kg·m-2·h-1,分离系数大于1000,且该法具有一定重复性。对合成的膜的渗透蒸发性能进行了详细研究。(4)采用微波合成法制备T型沸石膜。在423K下微波加热4h制备的T型沸石膜：348K下分离90wt.%乙醇/水,通量为1.36kg·m-2·h-,分离系数大于1000。更多还原

【Abstract】 Dehydration of organics for highly purified organic products is essential in the fine chemicals, petrochemical and pharmaceutical chemicals. The conventional separation process is energy intensive and low efficiency. Pervaporation is considered as the potential technology to replace conventional separation process, because of it’s high separation efficiency, low energy consumption, and low pollution. Dehydration of a large varieties of organic liquids in the actual industrial applications is under acidic conditions, such as purification of ethanol and isopropanol used as solvents in pharmaceutical chemicals and dehydration of ester products. Zeolite NaA membranes have become ideal materials on dehydration of organic by pervaporation due to its high hydrophilicity. However, zeolite NaA membranes can not be applied for dehydration of organic liquids containing an acid because of their instability in acidic media. Zeolite T membrane is acid-resistant while remaining hydrophilic, which has excellent pervaporation performance for dehydration of organic liquids. Zeolite T membrane has the potential for dehydration of organic by pervaporation in the presence of organic acid, such as esterification hybrid process and alcohol dehydration in fermentation engineering. Therefore, zeolite T membrane has a very broad application prospect. However, it’s found that mature preparation routes are still the urgent problems in study of zeolite T membrane.Secondary growth method is composed of deposition of zeolite seed crystals to form a seed layer and then crystallization of the seeded support to form a polycrystalline zeolite layer. The high quality of seed layer is the key to prepare high quality zeolite membranes by secondary growth method. So, seeding technology has become one of the hot spots. Microwave hydrothermal method is becoming the popular method for preparation of zeolite membranes in the recent years. It can shorten the synthetic time effectively, and the membrane prepared by microwave heating is thin and compact, and permeation performance has been improved.Based on the above research ideas, this paper firstly explored different sizes of zeolite T were synthesized to modify the support surface and be used as seeds. Then, zeolite T membranes were prepared by conventional hydrothermal method in gel solutions and microwave hydrothermal method in clear solutions respectively, to explore the mature preparation routes. Also, an effective seeding method was designed on the inexpensive macroporous support. The as-synthesized zeolite T membranes were characterized by X-ray diffraction(XRD) and scanning electron microscope(SEM). The main research results are briefly introduced as follows:(1) Zeolite T with4～6μm was synthesized by the formulation25SiO2:l Al2O3:6.5Na2O:2.25K2O:350H2O. Different sizes of zeolite T were synthesized by changing synthesis conditions with the formulation18.2SiO2:1Al2O3:4.2Na2O:1.5K2O:0.82TMAOH:212.7H2O.(2) Zeolite T membrane was synthesized by conventional heating in gel solutions. The influence of synthesis conditions were investigated. When zeolite T membrane was synthesized under conditions that include n(Na2O+K2O)/n(SiO2)=0.35, n(H2O)/n(SiO2)=30,373K and30h, the performance of as-synthesized membranes for90wt.%ethanol/water mixture was high with the flux up to1.67kg·m-2·h-1and the separation factor of1115.(3) The high quality of seed layer was obtained by two-stage varying-temperature hot dip-coating seeding method on the inexpensive macroporous support. The as-synthesized membranes have high performance with the water flux up to2.12kg·m-2·h-1and the separation factor was more than1000. The two-stage varying-temperature hot dip-coating seeding method has good reproducibility. The pervaporation performance of as-synthesized membrane was studied in detail.(4) Zeolite T membrane was synthesized by microwave heating in clear solutions. The influence of synthesis conditions were investigated. The as-synthesized membranes have high performance with the water flux up to1.36kg·m-2·h-1and the separation factor was more than1000at348K.更多还原