高温硅基陶瓷分离膜材料的制备与表征

发布时间：2018-04-08 13:13

本文选题：陶瓷膜　切入点：碳化硅　出处：《合肥工业大学》2015年硕士论文

【摘要】：陶瓷膜分离技术具有耐高温、耐腐蚀、分离效率高、耗能低及绿色环保等优点,在食品、化工、生物医药及环保等领域广泛应用。随陶瓷膜广泛应用,膜材料性能要求提高,使用环境更苛刻,传统的膜材料无法适用于高温腐蚀性等环境。本文以开发陶瓷膜材料,降低制备成本为研究目标,研究碳化硅(SiC)陶瓷膜支撑体和可作为膜材料的硅酸钇材料的制备与表征,取得如下工作成果：(1)采用溶胶包裹法低温制备了SiC陶瓷膜支撑体。采用溶胶包裹法在1100℃低温制备了气孔率高达49.58%的SiC陶瓷膜支撑体。该工艺制备的SiC陶瓷膜支撑体生坯烧结之后直径略有变大,发生不同程度的膨胀,随烧结助剂含量增加,样品的线收缩率不升反降,气孔率却在增加,这说明以九水硝酸铝和六水硝酸钇作为助烧剂,不仅降低烧结温度,还能起到造孔的作用,改善支撑体的宏观变化。在以2OpmSiC为骨料时,淀粉含量为6wt%,助烧剂含量为30wt%时,在1100℃下样品的负向线性收缩率低至0.83%。(2)采用分相法制备了非对称型结构的SiC中空纤维陶瓷膜。分相法与固相烧结相结合通过一步成型制备出非对称结构的SiC中空纤维陶瓷膜,不添加造孔剂也可制得气孔率高达53.83%的SiC膜管；制备的SiC膜管呈指孔结构层-海绵状结构层-指孔结构层结构,有利于提高膜的渗透性。烧结温度对其收缩率的变化影响均很小,轴向径向的线收缩率分别基本稳定在10.1%和9.0%。(3)首次采用EDTA-柠檬酸络合法成功合成了高纯度的纳米级的硅酸钇材料,并对合成机理进行探讨。该工艺前驱体pH值为9.38时在高于1050℃煅烧可以得到α-Y2Si2O7相,pH值为4时得到的是Y2SiO5相。这主要是因pH值不同,EDTA和柠檬酸络合能力及TEOS水解聚合能力也不同。获得的Y2Si207粉体具有葡萄状结构,此结构存在大量晶界,为其作为气体分离膜提供特殊的物理通道和机械强度保障。
[Abstract]:High temperature ceramic membrane separation technology has corrosion resistance, high separation efficiency, low energy consumption and green environmental protection and other advantages, is widely used in food, chemical, biological medicine and environmental protection etc.. With the wide application of ceramic membrane, membrane material performance requirements to improve the use of the environment more demanding, the traditional film material is not suitable for high temperature corrosion such environment. Based on the development of ceramic membrane materials, reduce the preparation cost as the research object, study on the synthesis and characterization of silicon carbide (SiC) ceramic membrane support and can be used as a membrane material of yttrium silicate material, made the following achievements: (1) low temperature preparation of SiC ceramic membrane supported by sol coating method using sol coated method in low temperature of 1100 DEG C to fabricate SiC ceramic membrane up to 49.58% porosity support. After the preparation process of SiC ceramic membrane support green sintering diameter slightly larger, the expansion of the, with the help of sintering Agent content increased, sample shrinkage rate declined, the porosity has increased, indicating that the nine water and six aqueous aluminum nitrate yttrium nitrate as sintering agent, not only reduce the sintering temperature, but also play the role of macro pore, improve the supporting body. Changes in the 2OpmSiC aggregate. The starch content of 6wt%, 30wt% can burn agent content, samples at 1100 DEG C, the negative linear shrinkage rate to 0.83%. (2) SiC hollow fiber membrane asymmetric structure were synthesized by phase separation method and solid phase sintering. Through the combination of one-step molding prepared SiC hollow fiber ceramic membrane asymmetric structure, adding pore forming agent can be prepared SiC film porosity up to 53.83% tubes; SiC membrane prepared by tube with a sponge like structure layer - finger structure layer - finger structure layer structure, improve the permeability of the membrane. The effect of sintering temperature on the shrinkage rate of change very small, Axial and radial shrinkage rate were basically stable at 10.1% and 9.0%. (3) for the first time using EDTA- citric acid complexing successful high purity nanometer yttrium silicate material was synthesized, and the synthesis mechanism was discussed. The process of precursor pH value was 9.38 higher than 1050 in calcined can get a -Y2Si2O7 phase. When the pH value is 4 by Y2SiO5 phase. This is mainly due to different value of pH, EDTA and citric acid complexing ability and TEOS hydrolysis polymerization is different. Y2Si207 powder obtained with grape like structure, the structure of the existence of a large number of grain boundaries, providing special physical channel and mechanical strength as the guarantee for the gas separation membrane.

【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ051.893

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