基于无机纳米粒子高通量双模板分子印迹膜的制备及性能研究

发布时间：2018-05-31 04:28

本文选题：双模板 + 分子印迹复合膜　；参考：《西南交通大学》2017年硕士论文

【摘要】：分子印迹膜兼具分子印迹技术与膜分离技术双重优点,但由于有机膜的机械强度较小,在分离过程中受压容易使印迹孔穴空间变形和互补官能团位置失稳,使得其分离效率大大降低。为了提高膜的机械性能和水通量,在制备过程中掺杂入无机纳米粒子制备出有机—无机杂化膜。本文使用紫外光引发原位聚合的方法,以PVDF为支撑膜,将无机纳米材料掺杂入铸膜液中,制备出含有无机纳米材料的阿魏酸分子印迹复合膜。利用红外光谱和扫描电镜测试了膜的结构和表面形貌,发现了纳米粒子是以纯物理方式共混的,且都分散在孔的周围,有利于维持膜的孔穴结构。通过平板超滤装置研究了分子印迹复合膜的分离性能、水通量和承压能力,研究结果表明改性后的分子印迹复合膜在保持高分离效率的前提下,承压能力和水通量都有了明显的改善。同时,实验发现添加0.5wt%-18 nm TiO2的改性膜性能最好,其承压能力在0.4 Mpa以上,分离因子在3.4左右,水通量为6696L·m-2·h-1。在前期实验的基础上,本文采用不同的方法制备出双模板分子印迹复合膜,并采用多种方式对膜的各项性能进行表征。本文探讨了以α-甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,阿魏酸和肉桂酸为双模板分子,偶氮二异丁腈为引发剂引发聚合反应,并采用共混法掺杂入纳米材料改善膜的机械强度和水通量,从而合成了具有高通量和高选择性的双模板分子印迹复合膜。本文探究了无机纳米材料的种类及其含量、引发剂的含量、模板分子与功能单体的比值以及合成方法(一步法或者两步法)对双模板分子印迹复合膜的性能的影响。研究发现合成的最优条件为:添加的纳米材料为18 nmTiO2,添加含量为1wt%,引发剂的含量为0.3 g,采用一步法合成,功能单体与模板分子的比值(F/T)为1:3。采用上述条件合成的双模板分子印迹复合膜对模板分子阿魏酸和肉桂酸的透过率均处在100%左右,与此同时对类似物咖啡酸、丁香酸的透过率也达到了 100%左右。然而对相对分子量大小相似,而结构差别比较大的葡萄糖的透过率处在60%左右。综上可知,制备的双模板分子印迹复合膜可特异性分离模板分子以及类似物,然而对结构相差比较大的物质具有较低的分离效率。可见,双模板分子印迹膜可专一性的识别同一类物质,因此,可将其应用于某些中药活性成分的选择富集和分离、食物中有毒物质的检测等。
[Abstract]:The molecularly imprinted membrane has the advantages of both molecular imprinting and membrane separation. However, due to the small mechanical strength of the organic membrane, it is easy to be subjected to pressure during the separation process to make the space deformation of the imprinted holes and the position of complementary functional groups unstable. The separation efficiency is greatly reduced. In this paper, in order to prepare ferulic acid molecularly imprinted composite films containing inorganic nanomaterials, the inorganic nanomaterials were doped into the casting solution with PVDF as the supporting membrane by the method of in situ polymerization initiated by ultraviolet light. The structure and surface morphology of the films were measured by infrared spectroscopy and scanning electron microscopy. It was found that the nanoparticles were blended in a pure physical manner and were dispersed around the pores, which was conducive to maintaining the pore structure of the films. The separation performance, water flux and pressure bearing capacity of the molecularly imprinted composite membrane were studied by a flat plate ultrafiltration device. The results showed that the modified molecularly imprinted composite membrane maintained high separation efficiency. Both the pressure bearing capacity and the water flux have been significantly improved. At the same time, it was found that the modified membrane with 0.5wt%-18 nm TiO2 had the best performance, its pressure bearing capacity was more than 0.4 Mpa, the separation factor was about 3.4, and the water flux was 6696 L m-2 h-1. On the basis of previous experiments, the double template molecularly imprinted composite membranes were prepared by different methods, and the properties of the membranes were characterized in various ways. The polymerization was initiated with 伪 -methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinking agent, ferulic acid and cinnamic acid as double template molecules and azodiisobutyronitrile as initiator. The high throughput and high selectivity double template molecularly imprinted composite membranes were synthesized by blending nanomaterials to improve the mechanical strength and water flux of the membranes. The effects of inorganic nanomaterials and their contents, initiator content, the ratio of template molecules to functional monomers and synthesis methods (one-step or two-step) on the properties of double-template molecularly imprinted composite films were investigated. It was found that the optimum conditions of synthesis were as follows: the addition of nano-materials was 18 nm TIO _ 2, the content of the initiator was 0.3 g, the ratio of functional monomer to template was 1: 3, the content of initiator was 0.3 g, the ratio of functional monomer to template was 1: 3. The transmissivity of the double template molecularly imprinted composite membrane to the template molecules ferulic acid and cinnamic acid is about 100%, and the transmittance of the analogue caffeic acid and eugenic acid is about 100%. However, the transmittance of glucose with similar molecular weight and structure is about 60%. It can be concluded that the double template molecularly imprinted composite membrane can specifically isolate template molecules and analogues, but it has a low separation efficiency for substances with large structural differences. Therefore, it can be applied to the selection, enrichment and separation of some traditional Chinese medicine active components, the detection of toxic substances in food and so on.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O631.3

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