【作者】 高晓劝；

【导师】 张裕卿；

【作者基本信息】 天津大学 ， 膜科学与技术， 2009， 硕士

【摘要】 黄酮类化合物是广泛存在于自然界的一大类化合物,数量种类繁多,且结构类型复杂多样。根据其结构的不同,黄酮化合物具有不同的生物活性和生理作用。采用传统分离方法无法实现对结构类似化合物的精确分离,膜分离方法也存在着选择性低的不足。分子印迹膜技术是在分子印迹技术和膜分离技术上发展起来的一种新型分离技术,能够实现对黄酮类化合物分子的专一性分离。但分子印迹膜技术的制备工艺复杂,可重复性差。而将制备好的分子印迹材料填充到聚合物中制备填充膜的技术则克服了这些缺点。因此,本文采用填充膜技术通过填充已合成好的分子印迹材料后制备出在水相中能够对复杂体系中某一特定物质具有专一识别功能的高选择性分离膜,同时对膜的透过机制及传质模型进行了研究。依据分子印迹技术原理,以氨丙基三乙氧基硅烷为功能单体,正硅酸乙酯为交联剂,木犀草素为模板分子,制备出木犀草素分子印迹材料。然后将其大量填充到聚砜材料中,采用相转化法制备出高选择性分离膜。该选择性分离膜在0.15MPa时通量可达到170.4L/(m2·h),在298.15K时,结合量为30.3mg/g,分离系数可达10.78。对该膜进行扫描电镜测试,结果表明高选择性分离膜中存在较为规整的孔结构,且与模板分子在大小和形状上相匹配。利用Material Studio软件模拟分子之间的相互作用,结果显示模板分子与聚合物材料之间存在多氢键的协同作用,且在水和乙醇极性溶液中能形成复合物。对该膜的结合性热力学和动力学进行分析,结果显示膜内孔穴与模板分子之间的匹配性较好,在构象和能量上都有利于模板分子的分离,进而能够实现对模板分子的专一性分离。本文还对该选择性分离膜的选择透过性机制进行了探讨,分析了膜内可能存在的孔道形式。从Piletsky提出的“门”模型出发,提出了分子印迹平板膜传质数学模型,并认为膜的表皮层对于模板分子的分离起到了重要作用。更多还原

【Abstract】 Flavonoids with huge diversity in the category and configuration are widespread in the nature. They have different biological and physiological activities according to their different configurations. Flavonoids with similar configuration can not be separated by traditional separation method and membrane separation technology whose selectivity is lower. Based on molecular imprinting and membrane separation technology, molecularly imprinted membrane (MIM) technology becomes one of the research issues. The prepared MIM can achieve the specific separation of flavonoids. Currently, drawbacks like complication and poor reproducibility of preparation technology have limited the broadly application of traditional molecularly imprinting membrane technology. The preparation technology of filled membrane by filling the prepared molecularly imprinted materials into the polymer overcomes these shortcomings. Therefore, the high selectively separation membrane with specific recognition and permeation performance for certain substance in complex system was prepared by filling the prepared molecularly imprinted materials according to filled membrane technology in this paper. The mechanism of membrane permeability and the mass transfer model were also studied.According to the molecularly imprinted technique, the luteolin molecularly imprinted materials (LUMs) were synthesized by copolymerization of aminopropyltriethoxysilane (APTES) as functional monomer and tetraethyl orthosilicate (TEOS) as the cross-linker in the presence of luteolin as the template molecule. High selectively separation membrane (HSM) was prepared by filling large amount of LUMs in the polysulfone through phase-inversion method. The flux of HSM was 170.4L/ (m2·h) at the pressure of 0.15MPa; the binding amount of HSM was 30.3mg/g and the separation factor was 10.78 at 298.15K. The scanning electron microscope (SEM) tests of HSM showed that there were regular channels with corresponded pore sizes matched with the template molecules in the HSM. The template molecules and the LUMs could form hydrogen bonds in aqueous solution and ethanol solution according to molecular simulation technology. The analysis on binding thermodynamics and kinetics of the HSM illustrated that the channels in the HSM matched well with the template molecules both in size and structure, and it was beneficial for the separation of the template molecule in conformation and energy. So it was probable to separate the template molecules specifically.The selective permeability mechanism of HSM and the forms of the channels in the HSM were also discussed in this paper. Considering“gate”model of Piletsky, a mathematical model of mass transfer in high selectively flat membrane was proposed to explain the law of separation, and the up-layer of the membrane was thought to play an important role in the separation process.更多还原