氧通道磁性复合膜的构建及其氧氮分离性能研究

Oxygen-enriched combustion is an effective measurement to control the formation of haze. So the research concerning the separation of oxygen/nitrogen mixture is of great significance on ruducing hazardous waste gases emission and preventing air pollution. Based on the magnetic dissimilarity and different exercise style of oxygen and nitrogen under the action of magnetic field, this subject aims at constructing a novel magnetic composite membrane (MCM) for air separation. In the membrane, porous core-shell magnetic nanorods (CS-MN) will be dispersed and oriented in ethylcellulose matrix to form low oxygen permeation-resistent channels. The main research contents are as follows: firstly, a series of CS-MN with MOF as the shell and Fe3O4 nanorod as the core will be prepared through layer-by-layer assembly method. The effects of MOF preparation conditions and assembly layer number on the physical/chemical structures and magnetic properties of CS-MN will be investigated. Then MCMs with different oriented degrees of CS-MN will be prepared by virtue of an external magnetic field. The aims of this section are; (1) grasp the effects of the viscosity of the system, solvent evaporation rate and external magnetic field intensity on the membrane microstructures, such as oriented degrees of CS-MN in the membrane, (2) clarify the key factors and mechanism of the "oxygen channel" formation in MCMs, (3) study the relationship between membrane ordered microstructures and oxygen/nitrogen separation performance of the magnetic membranes. In summary, the integration of the porosity of MOF, the orientation of magnetism and the high efficiency of membrane in this research will bring about a noval route and method for the structural design and high performance acquisition of oxygen/nitrogen separation membranes. Furthermore, it will promote the development of the science and technology about the separation of gases with different magnetic properties.

富氧燃烧是控制雾霾形成的有效措施之一，开展氧氮分离研究对减少有害气体排放、防治大气污染具有重要意义。基于氧氮磁性的差异和磁致运动规律的不同，本项目以多孔核-壳磁性纳米棒为磁性中心，乙基纤维素为聚合物基体，构建具有低扩散阻力氧传输通道的磁性复合膜并进行氧氮分离研究。采用层层自组装法，制备系列以MOF为壳、Fe3O4纳米棒为核的核-壳磁性纳米棒，探索反应条件和组装层数对纳米棒结构和磁性能的影响。通过耦合外加磁场法，制备纳米棒定向程度不同的磁性复合膜，考察体系粘度、溶剂挥发速率及外加磁场强度等因素对膜內纳米棒定向程度等微结构的影响规律，阐明磁性复合膜内有序氧通道形成的关键因素和机制；研究磁性复合膜有序微结构与氧氮分离性能的构效关系。项目研究集MOF的多孔性、磁的定向性及膜的高效性于一体，为氧氮分离磁性复合膜的结构设计及高性能获取提供新途径和新方法，同时也必将推进磁性相异气体分离科学和技术的发展。

富氧空气在能源、化工、医疗等工业领域应用广泛。开展高效的氧氮分离技术研究以获取富氧空气不仅能实现节能降耗，对治理雾霾、防治大气污染也具有重要意义。本项目基于氧氮磁性相异和磁致运动规律不同，以核-壳磁性纳米粒子、二维磁性纳米片等为磁性基元，以固有微孔聚合物、聚醚共聚酰胺等为聚合物基体，构建具有低扩散阻力氧传输通道的高性能磁性复合膜并用于氧氮分离。设计合成系列具有核-壳、二维片层等特殊结构的磁性复合粒子；通过考察成膜过程控制参数对磁性复合膜结构的影响规律，掌握了膜内构筑低阻力氧传输通道的有效途径；通过耦合外加磁场法，深入研究了磁性复合膜结构与氧氮分离性能的构-效关系，揭示了磁性复合膜氧氮分离的磁场强化机理，获得了系列高分离性能的磁性氧氮分离膜。磁性复合粒子中引入MOF壳层、GO片层能够提高Fe3O4在聚合物基体内的分散程度，改善磁性复合膜的机械性能；同时，MOF的多孔结构和GO二维片层结构均能在膜内形成低阻力的氧传输通道，从而提高O2的渗透性和O2/N2选择性；耦合外加磁场，可以强化顺磁性O2在膜内的渗透。外加磁场强度为56mT时，固有微孔聚合物磁性复合膜的O2渗透率为744Barrer，O2/N2选择性为3.67；聚醚共聚酰胺磁性复合膜的O2渗透率为20.83 Barrer，O2/N2选择性达到了6.28。项目研究集磁的定向性和膜的高效性于一体，为氧氮分离磁性复合膜的结构设计及高性能获取提供了新途径和新方法。