【作者】 陈坤；

【导师】 黄征青；

【作者基本信息】 湖北工业大学 ， 材料学， 2008， 硕士

【摘要】 本文介绍了超滤原理、应用概况、超滤存在的问题、防止超滤膜污染途径以及有机-无机膜的研究进展等。大量文献报道在有机膜中添加无机填料可以提高膜的耐污染性能、渗透性以及增强膜的机械强度和延长膜的使用寿命。而目前在有机-无机超滤膜的研究中添加的无机填料主要有SiO₂、Al₂O₃、ZrO₂、TiO₂等,以Fe₃O₄作为填料的研究尚不多见;Fe₃O₄不仅具有良好的亲水性,而且具有磁性,如果在制膜的过程中引入磁场的作用将改变Fe₃O₄的排列状态,进而会影响膜的结构和性能,但是目前这方面的研究尚未见报道。本文以聚砜（PSF）为基材,四氧化三铁（Fe₃O₄）为填料,二甲基乙酰胺（DMAC）为溶剂,聚乙烯吡咯烷酮（PVP）为添加剂配制膜液,采用浸没沉淀相转化法分别在有磁场和无磁场的作用下制备了聚砜-四氧化三铁超滤膜。采用错流过滤装置测试了膜的各项性能,用扫描电子显微镜表征了膜的断面和表面结构。结论如下:（1）在无磁场作用时,Fe₃O₄含量对非磁化超滤膜结构与性能的影响:当Fe₃O₄含量达到30wt%以上时,非磁化膜的截留率均在89%以上;并且随着Fe₃O₄含量的增加,非磁化膜的渗透通量增加,膜断面指状孔贯通性增强,皮层变薄。（2）在有磁场的作用时,Fe₃O₄含量对磁化超滤膜结构与性能的影响:当Fe₃O₄含量大于30wt%时候,磁化膜的截留率均在90%以上;随着Fe₃O₄含量的增加,磁化膜的渗透通量迅速增加,直到Fe₃O₄含量大于50wt%时,磁化膜的渗透通量不再随着Fe₃O₄含量的增加而增加。当Fe₃O₄含量为70wt%时,磁化膜的综合性能最好,纯水通量和截留率分别为104L/m2·h,95%。电镜图片显示,随着Fe₃O₄含量的增加,磁化膜断面指状孔的贯通性增强。（3）磁化和非磁化超滤膜结构与性能的差异:当Fe₃O₄含量达到30wt%以上时,在Fe₃O₄含量相同的情况下,磁化膜的渗透通量大于非磁化膜的渗透通量,Fe₃O₄含量越高,磁化膜与非磁化膜的这种差异越明显;直到Fe₃O₄含量达到50wt%以上时,磁化膜和非磁化膜的这种差异开始缩小。相对于非磁化膜而言,磁化膜的断面指状孔的贯通性较好。磁化膜表面呈山峰状结构,这种结构有利于提高磁化膜单位表面积上的微孔数目。总之,结果表明增加超滤膜中Fe₃O₄的含量可以提高超滤膜的综合性能,如果在制膜过程中引入磁场的作用,将会使超滤膜的综合性能进一步提高。更多还原

【Abstract】 This paper introduced the principle of UF, and expressed application and existing problems of UF as well as the methods of anti-fouling of membrane and the current research of organic - inorganic membranes. According to many studies, if adding inorganic-fillers, the anti-fouling and permeability of membrane can be improved, and also, mechanical strength, and the lifetime of membrane can be enhanced. And at present, in the research of organic-inorganic UF membrane, the main inorganic-fillers are SiO₂、Al2O₃、ZrO₂、TiO₂ and so on. Fe₃O₄ as a kind of inorganic-filler has seldom been used. Fe₃O₄ is not only excellently hydrophilc but also magnetic. If introducing magnetic effect, the form of Fe₃O₄ would be changed, so that the structure and properties of membrane can be influenced further. This research has not been reported until now.In this paper, PSF-Fe₃O₄ membrane was prepared by substrate material of PSF, the filler of Fe3o4, the solution of DMAC and the porogen of PVP under magnetic field or nonmagnetic field through the method of immersion precipitation phase inversion. The performance was investigated using cross-flow filtration equipment. The cross-sectional structure of the membranes was observed by SEM. The conclusions are as following:（1） The influence of the concentration of Fe₃O₄ to the performance and structure of non-magnetic UF membrane: When the concentration of Fe₃O₄ above 30wt%,the rejection of non-magnetic membrane above 89%, increasing the concentration of Fe₃O₄ can not only increase the infiltration flux, but also can enhance the connectivity of the finger-pore , the cortex become thinner with the concentration of Fe₃O₄ increased .（2） The influence of the concentration of Fe₃O₄ to the performance and structure of magnetic UF membrane: as the concentration of Fe₃O₄ reaching more than 30wt%, the rejection of magnetic membrane was above 90%, increasing the concentration of Fe₃O₄ can increase the infiltration flux of magnetic membrane rapidly, when the concentration of Fe₃O₄ above 50wt%, the infiltration flux of magnetic membrane will not enhance with the concentration of Fe₃O₄ increased. As the concentration of Fe₃O₄ reaching 70wt%, the synthetically properties of magnetic membrane was the best, the pure water flux and rejection are respectively 104L/m2·h and 95% at this time. The SEM pictures of the cross-sectional of magnetic membrane indicated that the connectivity of the finger-pore was enhanced with the concentration of Fe₃O₄ increased.（3） The differences of UF membrane structure and performance between magnetic membrane and non- magnetic membrane :under the condition that the concentration of Fe₃O₄ reaching more than 30wt%, when we have the same Fe₃O₄ concentration, the infiltration flux of magnetic membrane is higher than the magnetic membrane’s. The phenomenon is more obvious when the concentration of Fe₃O₄ is higher. Comparing non-magnetic membrane, the connectivity of the finger-pore is better in magnetic membrane. The magnetic-membrane surface was mountain-like structure which is propitious to increase porosity of probability on the surface of magnetic- membrane.In conclusion, the result indicated that increasing the concentration of Fe₃O₄ can enhance the synthetically properties of UF membrane. If we introducing the effect of magnetic field, the synthetically properties of UF membrane will be improved further.更多还原