聚合物嵌入型沸石咪唑酯类金属有机骨架膜的合成及性能研究

发布时间：2018-01-26 01:00

本文关键词： 金属有机骨架沸石咪唑酯类膜可规模放大合成嵌入改性气体分离　出处：《浙江工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：金属有机骨架(MOF_s)是一种新型的多孔晶体材料,具有规则的孔道结构以及丰富的物理、化学性质,并且可以通过合理地设计对其进行结构上和性质上的改变,因此,MOF_s材料在吸附、分离、催化、传感等领域展现出了广阔的应用前景。在近十年间,通过自组装而形成的MOF膜在分离领域取得了惊人的发展。目前,越来越多的研究团队在MOF膜材料、合成方法和分离性能等方面均取得了瞩目的成绩。然而,从工业应用的角度来考虑,MOF膜在合成方法和分离性能方面仍然很难满足实际需求,发展进入到了瓶颈时期。基于上述考虑,本文以ZIF-8为目标MOF材料,分别从合成方法和分离性能两个方面进行了研究。首先,本工作从合成方法的角度出发,结合膜接触器和界面合成的理论提出了一种新型可规模放大的MOF膜合成方法,这种方法摆脱了传统的高能耗的溶剂热的过程,避免MOF膜在装填过程中被破坏的风险,利用了界面合成的原理可以避免均相成核而导致的原料的浪费。利用这种方法,我们成功合成了连续的ZIF-8膜。我们采用SEM、XRD、EDS等手段对合成的ZIF-8膜进行了表征,确定了ZIF-8膜的形貌、结构方面的特征。通过考察前驱溶液浓度比例和合成时间对成膜的影响,我们初步分析了MOF膜的成膜机理,为后续其它种类的MOF膜的合成提供了理论支持。另一方面,为了提高MOF膜的分离性能,本工作在新型合成方法的基础上成功合成了聚合物(聚乙烯吡咯烷酮,PVP)嵌入的ZIF-8膜。聚合物在MOF中的嵌入使得MOF孔道结构发生改变,同时还能促进MOF晶体之间的互生生长,有效地减少甚至消除MOF膜中的纳米级缺陷,从而大幅提高MOF膜的气体分离性能。实验结果显示,PVP嵌入后ZIF-8颗粒变小,ZIF-8膜结构更加致密。通过对PVP嵌入的ZIF-8颗粒进行XRD、N2吸附测试和对ZIF-8复合膜进行FTIR表征,证明了PVP在ZIF-8中可嵌入性。最后我们对合成的PVP嵌入ZIF-8膜进行单组分气体渗透测试,实验结果显示相比于纯的ZIF-8膜,PVP嵌入ZIF-8膜气体通量有一定的降低,但H_2/CO_2理想分离选择性从4.97提高到了52.71,该值远远超过了大多数MOF膜对H_2/CO_2体系的分离效果。
[Abstract]:Organometallic organic frameworks (MOFs) is a new porous crystal material with regular pore structure and abundant physical and chemical properties. And the structure and properties of MOFs can be changed by reasonable design. Therefore, MOFs materials in adsorption, separation, catalysis, sensing and other fields have shown a broad application prospects in the recent decade. MOF membranes formed by self-assembly have made remarkable progress in the field of separation. At present, more and more research teams are in the field of MOF membrane materials. Remarkable achievements have been made in synthesis methods and separation properties. However, it is still difficult to meet the practical requirements of synthesis and separation properties of MOF membranes from the point of view of industrial application. The development has entered the bottleneck period. Based on the above considerations, the synthesis method and separation performance of ZIF-8 as the target MOF materials are studied in this paper. First of all. In this paper, from the point of view of synthesis method, a novel scalable MOF membrane synthesis method is proposed, which combines the theory of membrane contactor and interface synthesis. This method avoids the traditional solvothermal process of high energy consumption and avoids the risk of MOF film being destroyed in the filling process. The waste of raw materials caused by homogeneous nucleation can be avoided by using the principle of interfacial synthesis. Using this method, we have successfully synthesized continuous ZIF-8 films. The synthesized ZIF-8 films were characterized by EDS, and the morphology and structure of ZIF-8 films were determined. The effects of concentration ratio of precursor solution and synthesis time on the formation of ZIF-8 films were investigated. We preliminarily analyzed the mechanism of MOF membrane formation, which provided theoretical support for the subsequent synthesis of other kinds of MOF membrane. On the other hand, in order to improve the separation performance of MOF membrane. Based on the new synthesis method, the ZIF-8 film embedded in polyvinylpyrrolidone (PVP) was successfully synthesized. The intercalation of the polymer in MOF changed the pore structure of MOF. At the same time, it can promote the mutual growth of MOF crystals, reduce or even eliminate the nano-scale defects in MOF films, thus greatly improve the gas separation performance of MOF films. The experimental results show that. The structure of ZIF-8 membrane became denser after ZIF-8 particles were embedded in PVP. XRD was carried out on ZIF-8 particles embedded in PVP. N2 adsorption test and FTIR characterization of ZIF-8 composite membrane. The embeddedness of PVP in ZIF-8 was proved. Finally, we tested the PVP embedded ZIF-8 membrane by one component gas permeation test, and the experimental results showed that compared with the pure ZIF-8 membrane. The gas flux of PVP embedded in ZIF-8 membrane decreased to a certain extent, but the ideal separation selectivity of H _ 2 / COS _ 2 increased from 4.97 to 52.71. This value far exceeds the separation effect of most MOF membranes on the HSP 2 / COSP 2 system.
【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ051.893

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