外压式平板蜂窝状薄壁陶瓷微滤膜的制备和表征

发布时间：2018-05-21 12:43

  本文选题：陶瓷微滤膜 + 外压式薄壁支撑体　； 参考：《景德镇陶瓷学院》2015年硕士论文

【摘要】：陶瓷膜因机械强度高,耐腐蚀、易于再生等优点,在生物医药、化工及环保等领域得到广泛应用,成为重点研发的分离技术之一。因易于密封,现有的陶瓷膜多采用内压式,即分离膜层在膜孔道表面,料液从膜孔道内流动,膜间压从内向外。但该构型类似鸡蛋壳的力学结构,凹面的作用力相对集中,承受的压力相对较小,因此,内压式陶瓷膜需要更高的机械强度,目前多采用增加支撑体厚度的方式来加以实现,最薄壁处厚度在2mm以上。这必然增加陶瓷膜的渗透阻力,降低膜的通量。外压式陶瓷膜的分离膜层在外侧,料液的膜问压从外向内,膜构型的作用面比较分散,所以在相同膜间压条件下,外压式陶瓷膜支撑体的厚度可明显减小,从而减少膜的渗透阻力。但是,陶瓷膜支撑体的薄壁化对支撑体的成型、煅烧,膜层的制备等提出更高的技术要求,成为外压式薄壁陶瓷膜的制备与应用亟待解决的关键技术问题。本文研究了外压式平板状蜂窝陶瓷薄壁堇青石微滤膜的制备：采用挤出成型法制备了堇青石支撑体,通过控制泥料组成、干燥条件和烧结工艺,获得线性度良好的平板状蜂窝陶瓷膜支撑体；通过采用适度提高堇青石悬浮液固含量的方法,在薄壁平板状蜂窝支撑体上制备出膜层厚度均匀、无缺陷的中间层和顶层微滤膜；研究了悬浮液固含量、浸浆时间和悬浮液粘度对堇青石膜层厚度的影响,并分析了湿膜的形成机理,同时研究了干燥工艺和烧结制度对膜层孔径分布的影响。得到如下结论：(1)通过控制挤出、干燥、烧结等工艺制备出线性度良好的平板状蜂窝陶瓷膜支撑体,支撑体的尺寸为1000mm×95mm×13mm(长×宽×高),壁厚仅1mm,含双排渗透通道。经烧结温度为1350℃,保温1.5h,所得支撑体的孔隙率为50%,平均孔径为4.25μm,弯折强度为6.0MPa。(2)为解决支撑体厚度减少导致的湿膜厚度降低,易产生膜缺陷的问题,通过增加悬浮液固含量方法提高湿膜厚度。湿膜厚度随着悬浮液固含量的增加而增加,当悬浮液固含量为30%时,所得膜层厚度为30μm,平均孔径为0.65μm,膜面平整,最大孔仅为1.1μm。毛细管吸附机理对湿膜厚度的增加贡献增大,但贡献率减少。随着悬浮液粘度的增加,薄膜涂覆机理对成膜作用贡献量增加。(3)顶层悬浮液固含量为15%,涂膜时间为25s时,膜层厚度为101μm,最大孔为0.35μm,平均孔径为0.241μm。得到性能良好的平板状蜂窝陶瓷薄壁堇青石微滤膜。
[Abstract]:Because of its high mechanical strength, corrosion resistance and easy regeneration, ceramic membrane has been widely used in biomedical, chemical and environmental protection fields, and has become one of the key research and development of separation technology. Because it is easy to seal, most of the existing ceramic membranes adopt the internal pressure type, that is, the separation membrane layer is on the surface of the membrane channel, the material liquid flows through the membrane pore channel, and the intermembrane pressure flows from the inside out. However, the structure is similar to the mechanical structure of the egg shell. The concave force is relatively concentrated and the pressure is relatively small. Therefore, the internal pressure ceramic membrane needs higher mechanical strength. At present, it is usually realized by increasing the thickness of the support. The thin-wall thickness is above 2mm. This will increase the permeation resistance of ceramic membrane and reduce the flux of the membrane. The separation membrane layer of external pressure ceramic membrane is outside, the membrane pressure of material liquid is from outside to inside, the action surface of membrane configuration is dispersed, so under the same intermembrane pressure condition, the thickness of external pressure ceramic membrane support can be reduced obviously. Thus reducing the membrane permeability resistance. However, the thin-walled ceramic membrane support has put forward higher technical requirements for the shaping, calcination and preparation of the film layer, which has become a key technical problem to be solved in the preparation and application of external pressure thin wall ceramic membrane. In this paper, the preparation of thin wall cordierite microfiltration membrane of external pressure honeycomb ceramics was studied. Cordierite support was prepared by extrusion molding, and the composition of clay, drying conditions and sintering process were controlled. The flat honeycomb ceramic membrane support with good linearity was obtained, and the thin wall flat honeycomb membrane with uniform thickness and no defect was prepared by increasing the cordierite suspension liquid and solid content appropriately, and the thin wall flat honeycomb support was prepared by the method of increasing the content of cordierite suspensions. The effects of solid content of suspension, soaking time and viscosity of suspension on the thickness of cordierite film were studied. The formation mechanism of wet film was analyzed, and the effects of drying process and sintering system on the pore size distribution of cordierite film were studied. The following conclusions are obtained: by controlling extrusion, drying and sintering, the flat honeycomb ceramic membrane support with good linearity has been prepared. The size of the support is 1000mm 脳 95mm 脳 13mm (length 脳 width 脳 high), and the wall thickness is only 1 mm, which contains double permeable channels. With sintering temperature of 1350 鈩，

本文编号：1919245