【作者】 周术元；

【导师】 朱广山；

【作者基本信息】 吉林大学 ， 无机化学， 2014， 博士

【摘要】 金属有机骨架（MOFs）化合物结合无机和有机孔材料的优点，是由无机金属和有机配体构筑而成的晶体化合物，由于金属离子和配体的多样性可以设计多种结构拓扑的MOFs材料，具有良好的稳定性、有序度、高的表面积、可修饰性等特点，也正是MOFs材料独特的结构性能使其应用在制备优越特性的膜中。在过去的十多年里，MOF膜材料广泛应用于气体分离、催化、光学、传感器等诸多领域。金属有机骨架化合物具有均匀孔径、对特定气体具有高的吸附能力等特点，使得MOF膜对特定气体具有优异的选择渗透性，而引起其在气体分离中的应用。Cu3(BTC)2金属有机骨架化合物是由铜离子与1，3，5-均苯三酸形成的‘paddle-wheel’三维结构孔材料，孔径大小约0.9nm。我们用晶种二次生长方法，在预先用壳聚糖修饰的α-Al2O3中空陶瓷纤维（HCFs）管状载体上成功制备了Cu3(BTC)2MOF膜材料。选择一种新的、具有高机械强度和高比表面积的中空陶瓷纤维作为载体，简单的方法制备了大小适中的300nm Cu3(BTC)2晶种，既适合用浸渍-提拉法在HCFs上涂晶种，又不会堵塞HCFs载体。用具有多氨基和羟基的壳聚糖来增强载体与膜间的作用力。所合成的Cu3(BTC)2膜对双组分混合气体H2/N2，H2/CO2和H2/CH4进行气体分离测试，对氢气具有高的选择渗透性，分离指数分别为8.66，13.56和6.19，氢气的渗透量在3.23×10-8mol·m-2·s-1·Pa-1–4.1×10-8mol·m-2·s-1·Pa-1范围。此外，研究了温度、压力、测试时间对Cu3(BTC)2膜的影响，在温度达到313K时，一个标准大气压下，Cu3(BTC)2膜对H2具有最高的选择性。Cu3(BTC)2膜对氢气具有较高的渗透选择能力同时具有很好的稳定性。[Al4(OH)2(OCH3)4(H2N-BDC)3]·xH2O（CAU-1）是由铝离子和氨基对苯二甲酸配体形成的三维结构MOFs材料，具有扭曲八面体和扭曲四面体两种类型笼子，可进出气体的窗口都是0.38nm三角形窗口。通过在载体表面预涂大小均一的500nm晶种进行二次生长，利用“双铝源”方法成功制备了α-Al2O3中空陶瓷纤维（HCFs）支持的连续、高质量，厚度约4μm的CAU-1膜。能量散射X射线光谱（EDS）证明HCFs载体具有双重作用，既做载体，又提供部分铝源参加CAU-1膜的合成。通过对双组分混合气体H2/N2，H2/CO2和H2/CH4进行气体分离测试，分析得出CAU-1膜对氢气具有高的渗透选择性，分离指数分别为10.33，12.34和10.42。结合气体自身的扩散能力和动力学直径，CAU-1对四种气体的吸附能力和窗口大小分析，分离机理属于分子筛分。不同温度，压力、测试时间下的气体分离测试表明CAU-1膜具有高的稳定性和可重复性。MOFs有机配体通常带有N，P或S等元素，一些元素在酸性溶液中对金属具有一定的防腐蚀作用，因此MOFs另一新的应用正处于起步阶段。而我们探索发现了一种在碱性条件下，同样具有好的抗腐蚀保护作用的MOF膜材料。分子筛咪唑基骨架化合物（ZIF-8）是由锌离子与2-甲基咪唑配体形成的三维结构MOFs材料，具有强的疏水性和稳定性，在沸水，沸碱液中都具有好的稳定性。我们用一种绿色溶剂氯化胆碱和尿素组成的低共熔物，在锌片载体表面预涂晶种进行二次生长，“双锌源”辅助法成功制备了具有抗腐蚀保护性能的ZIF-8膜。用氯化胆碱和尿素低共熔物作溶剂，由于没有蒸汽压，可以在敞开的容器中进行膜的合成反应，为工业化大规模生产提供可能。再者，低共熔物具有双重作用，一是堵塞ZIF-8孔道，阻碍腐蚀性媒介从孔道进入腐蚀载体；二是季铵盐-氯化胆碱本身具有抗腐蚀作用。ZIF-8膜和空白锌片载体分别在3.5wt%NaCl腐蚀液中进行极化曲线测试，ZIF-8膜获得低的腐蚀电流密度和向正移的腐蚀电位，这表明无论在动力学上，还是在热力学上，ZIF-8膜对锌片都具有好的抗腐蚀保护性能。此外，分别在25℃和45℃高浓度3M KOH溶液中进行析氢测试，空白锌片载体的析氢速率约是ZIF-8膜的4倍，进一步说明ZIF-8膜具有良好的抗腐蚀保护能力。更多还原

【Abstract】 Metal-organic frameworks (MOFs) take the advantages of both organic andinorganic porous materials, built by metal ions and organic linker often causingfascinating structural topologies. MOFs porous materials also have the charactersof well stability and ordered structures, high suface areas and tailored properties,which make MOFs porous materials distinguish for the synthesis of excellentmembranes. In the last decade, MOF membranes are widely used in various fields,such as gas separation, catalyst, optical device, sensor and so on.MOFs possess uniform pore size and adsorption ability of gases, whichmake MOF membranes have outstanding perm-selectivity with specific gases andhave attracted the application in gas separation.Cu3(BTC)2metal-organic frameworks with three-dimensional ‘paddle-wheel’structure is constructed by copper ion and1,3,5-benzene acid and with the poresize of0.9nm. We have successfully fabricated Cu3(BTC)2membranes using asecondary growth method on pre-seeded α-Al2O3hollow ceramic fibers (HCFs)which are already modified with chitosan. A new support named HCFs with highmechanical strength and specific surface area are introduced. The300nmCu3(BTC)2seeds have been prepared in a simple approach, which are suitable forseeding without blocking the pore of HCFs support. Chitosan is used to strengthenthe binding force between HCFs support and the seeds on account of its fertileamino and hydroxyl groups. The performance of as-synthesized Cu3(BTC)2membranes are investigated by binary gas separation of H2/N2，H2/CO2andH2/CH4. The Cu3(BTC)2membranes show high H2perm-selectivity with theseparation factors are8.66,13.56and6.19separately and the permeance of H2isin the range of3.23×10-8mol·m-2·s-1·Pa-1to4.1×10-8mol·m-2·s-1·Pa-1. Besides,thermal, pressure and testing time effect are studied on H2separation. When thetemperature arrived at313K with a pressure of1atm, the selectivity ofCu3(BTC)2towards H2reaches the highest value. Cu3(BTC)2membrane alsomaintain well stability of perm-selectivity over long time gas separation.[Al4(OH)2(OCH3)4(H2N-BDC)3]·xH2O（CAU-1）is formed by aluminiumion and2-amino-1,4-benzenedicarboxylic acid (2-NH2-H2BDC) with a three- dimensional framework. There are two cages in the structure of CAU-1, which aredistorted octahedron and distorted tetrahedron with accessible window size of0.38nm. Continuous and high quality CAU-1membranes with a thinkness of4μmhave been successfully prepared by ‘dual-Al-source’ approach on pre-seeded α-Al2O3hollow ceramic fibers (HCFs). Energy-dispersive X-ray spectroscopy showsthe roles of HCFs support are dual, both as a support and suppling part of Al metalfor the synthesis of CAU-1. The performance of CAU-1membrane is examinedby the separation of two binary mixtures H2/N2, H2/CO2and H2/CH4, and theseparation factors are10.33,12.34and10.42, respectively. Taking advantages ofthe diffusion abilities and the kinetic diameters of the gas, the adsorption abilitiestowards four gases and the window size of CAU-1crystal, the mechanism ofCAU-1for gas separation is molecular sieving. The CAU-1membranes alsopossess high stability and reproducibility at different temperatures, pressures andwith long time testing.N, P or S element generally exists in the organic linker of MOFs, which hascorrosion resistance in acid liquor. Thus, MOFs with another new application is intheir infancy. We explored a new MOF membrane material with well anti-corrosion protection ability even in the alkaline.Super-hydrophobic and stable zeolitic imidazolate framework-8(ZIF-8) iscomposed of Zn ion and2-methylimidazole organic as a linker with three-dimensional structure. Even in the boil water and boil alkaline, ZIF-8crystals stillobtain good stability. Green eutectic mixture formed with choline chloride andurea is used as solvent,‘dual-Zn-source’ method is employed to prepare ZIF-8membrane with anti-corrosion performance on pre-seeded Zn slice. Owing to novapour pressure exists in choline chloride and urea eutectic mixture, themembrane could be made in an open vessel, which is benefit the industrialproduction. What’s more, the eutectic mixture have two roles, firstly, ZIF-8channel is blocked by eutectic mixture to hamper the corrosive medium destroythe Zn support by accessing into the channel of ZIF-8. Scondly, choline chlorideas a quaternary ammonium salt has the ability of corrosion protection. Theperformance of ZIF-8membrane and Zn substrate is studied by polarizationtesting in3.5wt%NaCl solution. The corrosion current density of ZIF-8 membrane decreased and the corrosion potential shifted to the positive direction,indicating that both in dynamics and thermodynamics ZIF-8membrane owns goodati-corrosion performance. Furthermore, H2evolution testing is investigated in3M KOH at25℃and45℃, respectively. The H2evolution rate of blank Znsubstrate is nearly4fold compared with ZIF-8membrane, it is implied once moreZIF-8membrane has the ability of corrosion protection.更多还原