自具微孔聚合物磁性混合基质膜的制备及其氧氮渗透性能研究
发布时间：2018-07-29 20:02
【摘要】：氧气和氮气广泛应用于能源、医疗、食品保鲜等工业领域。工业上常采用深冷精馏或变压吸附分离技术来获得氧氮气体。与这两种技术相比,气体膜分离技术具有节能、环保等诸多优点。近年来,磁性混合基质膜因具有独特的氧氮分离机制受到了人们的广泛关注。磁性混合基质膜是由磁性基元嵌入聚合物中形成的非均相体系。它利用氧氮分子的磁性质差异以及磁性基元/聚合物界面间隙的筛分作用,能够实现对氧氮分离过程的强化,因而磁性混合基质膜具有良好的应用前景。本文分别以四氧化三铁(Fe_3O_4)、聚多巴胺修饰四氧化三铁(Fe_3O_4@PDA)和有机金属骨架化合物包覆四氧化三铁(Fe_3O_4@ZIF-8)三种粒子为磁性基元,以自具微孔聚合物(PIM-1)为聚合物基体,采用溶剂挥发法制备了PIM-1/Fe_3O_4、PIM-1/Fe_3O_4@PDA和PIM-1/Fe_3O_4@ZIF-8三种磁性混合基质膜,系统研究了磁性基元的添加量、尺寸、表面修饰层结构以及外加磁场强度等因素对磁性混合基质膜的理化结构及其氧氮渗透性能的影响。全文的研究内容及结论如下:(1)以溶剂挥发法制备了PIM-1/Fe_3O_4和PIM-1/Fe_3O_4@PDA磁性混合基质膜。从PIM-1/Fe_3O_4和PIM-1/Fe_3O_4@PDA磁性混合基质膜的氧氮渗透性差异可以看出,致密聚多巴胺层的引入能有效改善磁性基元/聚合物界面缺陷,同时增强磁性混合基质膜的机械性能,但导致了磁性混合基质膜的氧氮渗透性能的下降。在添加量为2 wt%,外加磁场强度为56 mT时,PIM-1/Fe_3O_4@PDA磁性混合基质膜的气体渗透性能有最大值,此时O2的渗透系数为616 Barrer,O_2/N_2选择性为3.48。(2)采用原位生长法合成Fe_3O_4@ZIF-8磁性核壳基元,并将其嵌入PIM-1聚合物中,制备出PIM-1/Fe_3O_4@ZIF-8磁性混合基质膜。制备的Fe_3O_4@ZIF-8磁性核壳基元具有微孔结构,BET比表面积为552.8 m2/g,SF中值孔径为0.629 nm。对比PIM-1/Fe_3O_4和PIM-1/Fe_3O_4@ZIF-8磁性混合基质膜的氧氮渗透性差异可以看出,Fe_3O_4@ZIF-8磁性核壳基元的多孔ZIF-8层能增加磁性基元/聚合物界面的亲和力,同时为O2分子提供高效的渗透通道。当Fe_3O_4@ZIF-8磁性核壳基元添加量增加时,PIM-1/Fe_3O_4@ZIF-8磁性混合基质膜的机械性能和氧氮选择性均呈现先增后减的趋势,而气体渗透系数则不断增大。在添加量为8 wt%,外加磁场强度为56 mT时,磁性混合基质膜的O2渗透系数达到967 Barrer,O_2/N_2选择性达到3.17,这一结果接近2008年Robeson上限,表现出优良的O_2/N_2渗透性能。(3)将带有不同Fe_3O_4核粒径和不同ZIF-8壳层厚度的Fe_3O_4@ZIF-8磁性核壳基元嵌入聚合物PIM-1中,制备出粒子核壳结构不同的PIM-1/Fe_3O_4@ZIF-8磁性混合基质膜。实验结果显示随着ZIF-8壳层厚度的增大,磁性混合基质膜的机械性能和氧氮渗透性不断提高。当ZIF-8壳层厚度达到40 nm,外加磁场强度为56 mT时,磁性混合基质膜的O2渗透系数为831 Barrer,O_2/N_2选择性为3.78。随着Fe_3O_4@ZIF-8粒子核粒径的增加,磁性混合基质膜的机械性能逐渐降低,而氧氮渗透性能逐渐提高。当Fe_3O_4@ZIF-8粒子的核粒径为200 nm,外加磁场强度为56 mT时,磁性混合基质膜的O2渗透系数为744Barrer,O_2/N_2选择性为3.67。
[Abstract]:Oxygen and nitrogen are widely used in the industrial fields of energy, medical treatment, food preservation and other industrial fields. The technology of cryogenic distillation or pressure swing adsorption separation is often used in industry to obtain oxygen and nitrogen gases. Compared with these two technologies, gas membrane separation technology has many advantages, such as energy saving and environmental protection. In recent years, magnetic mixed matrix membrane has a unique mechanism of oxygen and nitrogen separation. The magnetic mixed matrix film is an heterogeneous system formed by the magnetic matrix element embedded in the polymer. It can be used to strengthen the process of the separation of oxygen and nitrogen by using the difference of magnetic properties of oxygen and nitrogen molecules and the screening effect of the interface gap between the magnetic radical and polymer. Therefore, the magnetic mixed matrix film has good application. In this paper, three particles of iron oxide modified iron oxide (Fe_3O_4), polydopamine modified iron oxide (Fe_3O_4@PDA) and organometallic skeleton compounds coated with iron oxide (Fe_3O_4@ZIF-8) were used as the magnetic radicals, and PIM-1/Fe_3O_4, PIM-1/Fe_3O_4@PDA was prepared by solvent evaporation method with the microporous polymer (PIM-1) as the polymer matrix. And PIM-1/Fe_3O_4@ZIF-8 three kinds of magnetic mixed matrix films, the effects of the addition amount, size, surface modification layer structure and magnetic field strength on the physical and chemical structure and oxygen and nitrogen permeability of the magnetic mixed matrix film are systematically studied. The contents and conclusions of the full text are as follows: (1) PIM-1/Fe is prepared by solvent evaporation method. _3O_4 and PIM-1/Fe_3O_4@PDA magnetic mixed matrix films can be seen from the difference of oxygen and nitrogen permeability between PIM-1/Fe_3O_4 and PIM-1/Fe_3O_4@PDA magnetic mixed matrix. The introduction of dense polydopamine can effectively improve the interfacial defects of magnetic element / polymer and enhance the mechanical properties of magnetic mixed matrix, but it leads to magnetic mixture. The permeability of oxygen and nitrogen in the plasma membrane is decreased. When the addition amount is 2 wt% and the external magnetic field intensity is 56 mT, the gas permeability of the PIM-1/Fe_3O_4@PDA magnetic mixed matrix film has the maximum value. The permeability coefficient of the O2 is 616 Barrer, and the O_2/N_2 selectivity is 3.48. (2) using in situ growth method to synthesize the Fe_3O_4@ZIF-8 magnetic core shell primitives and embed them in P. In the IM-1 polymer, PIM-1/Fe_3O_4@ZIF-8 magnetic mixed matrix is prepared. The Fe_3O_4@ZIF-8 magnetic core element has microporous structure, the specific surface area of BET is 552.8 m2/g, the median pore size of SF is 0.629 nm. and the difference of oxygen and nitrogen permeability of PIM-1/Fe_3O_4 and PIM-1/Fe_3O_4@ZIF-8 magnetic mixed matrix can be seen, Fe_3O_4@ZIF-8 magnetic properties can be seen. The porous ZIF-8 layer of the nuclear shell element can increase the affinity of the magnetic element / polymer interface and provide an efficient permeable channel for the O2 molecules. When the addition of the Fe_3O_4@ZIF-8 magnetic core element is increased, the mechanical properties and the oxygen and nitrogen selectivity of the PIM-1/Fe_3O_4@ZIF-8 magnetic mixed matrix film all increase first and then decrease, and the gas permeation system is used. When the addition amount is 8 wt% and the external magnetic field strength is 56 mT, the O2 permeability coefficient of the magnetic mixed matrix is 967 Barrer and the O_2/N_2 selectivity reaches 3.17. This result is close to the upper limit of Robeson in 2008 and shows excellent O_2/N_2 permeability. (3) there will be Fe_3O_4 with different Fe_3O_4 kernel diameter and different ZIF-8 shell thickness. The @ZIF-8 magnetic core shell element is embedded in the polymer PIM-1, and the PIM-1/Fe_3O_4@ZIF-8 magnetic mixed matrix film with different core shell structure is prepared. The experimental results show that the mechanical properties and oxygen nitrogen permeability of the magnetic mixed matrix film are increasing with the increase of the thickness of the ZIF-8 shell. When the thickness of the ZIF-8 shell reaches 40 nm, the external magnetic field strength is 56. At mT, the O2 permeability coefficient of the magnetic mixed matrix is 831 Barrer, and the selectivity of O_2/N_2 is 3.78. with the increase of the particle size of Fe_3O_4@ZIF-8 particles, the mechanical properties of the magnetic mixed matrix gradually decrease and the oxygen nitrogen permeation performance gradually increases. When the particle size of the Fe_3O_4@ZIF-8 particles is 200 nm and the external magnetic field strength is 56 mT, the magnetic Mixture Base The O2 permeability coefficient of plasma membrane is 744Barrer and O_2/N_2 selectivity is 3.67.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ051.893
本文编号：2153839
[Abstract]:Oxygen and nitrogen are widely used in the industrial fields of energy, medical treatment, food preservation and other industrial fields. The technology of cryogenic distillation or pressure swing adsorption separation is often used in industry to obtain oxygen and nitrogen gases. Compared with these two technologies, gas membrane separation technology has many advantages, such as energy saving and environmental protection. In recent years, magnetic mixed matrix membrane has a unique mechanism of oxygen and nitrogen separation. The magnetic mixed matrix film is an heterogeneous system formed by the magnetic matrix element embedded in the polymer. It can be used to strengthen the process of the separation of oxygen and nitrogen by using the difference of magnetic properties of oxygen and nitrogen molecules and the screening effect of the interface gap between the magnetic radical and polymer. Therefore, the magnetic mixed matrix film has good application. In this paper, three particles of iron oxide modified iron oxide (Fe_3O_4), polydopamine modified iron oxide (Fe_3O_4@PDA) and organometallic skeleton compounds coated with iron oxide (Fe_3O_4@ZIF-8) were used as the magnetic radicals, and PIM-1/Fe_3O_4, PIM-1/Fe_3O_4@PDA was prepared by solvent evaporation method with the microporous polymer (PIM-1) as the polymer matrix. And PIM-1/Fe_3O_4@ZIF-8 three kinds of magnetic mixed matrix films, the effects of the addition amount, size, surface modification layer structure and magnetic field strength on the physical and chemical structure and oxygen and nitrogen permeability of the magnetic mixed matrix film are systematically studied. The contents and conclusions of the full text are as follows: (1) PIM-1/Fe is prepared by solvent evaporation method. _3O_4 and PIM-1/Fe_3O_4@PDA magnetic mixed matrix films can be seen from the difference of oxygen and nitrogen permeability between PIM-1/Fe_3O_4 and PIM-1/Fe_3O_4@PDA magnetic mixed matrix. The introduction of dense polydopamine can effectively improve the interfacial defects of magnetic element / polymer and enhance the mechanical properties of magnetic mixed matrix, but it leads to magnetic mixture. The permeability of oxygen and nitrogen in the plasma membrane is decreased. When the addition amount is 2 wt% and the external magnetic field intensity is 56 mT, the gas permeability of the PIM-1/Fe_3O_4@PDA magnetic mixed matrix film has the maximum value. The permeability coefficient of the O2 is 616 Barrer, and the O_2/N_2 selectivity is 3.48. (2) using in situ growth method to synthesize the Fe_3O_4@ZIF-8 magnetic core shell primitives and embed them in P. In the IM-1 polymer, PIM-1/Fe_3O_4@ZIF-8 magnetic mixed matrix is prepared. The Fe_3O_4@ZIF-8 magnetic core element has microporous structure, the specific surface area of BET is 552.8 m2/g, the median pore size of SF is 0.629 nm. and the difference of oxygen and nitrogen permeability of PIM-1/Fe_3O_4 and PIM-1/Fe_3O_4@ZIF-8 magnetic mixed matrix can be seen, Fe_3O_4@ZIF-8 magnetic properties can be seen. The porous ZIF-8 layer of the nuclear shell element can increase the affinity of the magnetic element / polymer interface and provide an efficient permeable channel for the O2 molecules. When the addition of the Fe_3O_4@ZIF-8 magnetic core element is increased, the mechanical properties and the oxygen and nitrogen selectivity of the PIM-1/Fe_3O_4@ZIF-8 magnetic mixed matrix film all increase first and then decrease, and the gas permeation system is used. When the addition amount is 8 wt% and the external magnetic field strength is 56 mT, the O2 permeability coefficient of the magnetic mixed matrix is 967 Barrer and the O_2/N_2 selectivity reaches 3.17. This result is close to the upper limit of Robeson in 2008 and shows excellent O_2/N_2 permeability. (3) there will be Fe_3O_4 with different Fe_3O_4 kernel diameter and different ZIF-8 shell thickness. The @ZIF-8 magnetic core shell element is embedded in the polymer PIM-1, and the PIM-1/Fe_3O_4@ZIF-8 magnetic mixed matrix film with different core shell structure is prepared. The experimental results show that the mechanical properties and oxygen nitrogen permeability of the magnetic mixed matrix film are increasing with the increase of the thickness of the ZIF-8 shell. When the thickness of the ZIF-8 shell reaches 40 nm, the external magnetic field strength is 56. At mT, the O2 permeability coefficient of the magnetic mixed matrix is 831 Barrer, and the selectivity of O_2/N_2 is 3.78. with the increase of the particle size of Fe_3O_4@ZIF-8 particles, the mechanical properties of the magnetic mixed matrix gradually decrease and the oxygen nitrogen permeation performance gradually increases. When the particle size of the Fe_3O_4@ZIF-8 particles is 200 nm and the external magnetic field strength is 56 mT, the magnetic Mixture Base The O2 permeability coefficient of plasma membrane is 744Barrer and O_2/N_2 selectivity is 3.67.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ051.893
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