金属—有机框架膜的制备、后功能化修饰及其性能研究

发布时间：2018-05-19 07:08

本文选题：金属-有机框架材料 + 膜　；参考：《浙江大学》2014年博士论文

【摘要】：金属-有机框架材料(Metal-organic frameworks,简称MOFs)作为一种新型的多孔无机-有机杂化晶态材料,在气体存储与分离、发光、传感等领域具有重大的应用前景,并受到广泛的关注。膜材料具有高效、节能、经济等特点,而且还能将应用范围拓展到一些气态介质领域,如气体膜分离、气体传感等。目前,MOF膜的研究还处于初始阶段,针对连续密堆积的MOF膜的制备和后功能化修饰的研究还很少。基于气体分子与MOF膜孔径的尺寸差异和气体分子相互间的分子量差异,有时难以对尺寸和分子量相近的气体实现较好的分离,因而利用气体分子与MOF膜孔洞表面的官能团之间不同的相互作用实现气体的高效分离成为一种新的思路。MOFs材料在荧光探测领域的研究主要集中于粉体材料对液体中小分子、离子等的探测,这极大限制了对气态介质的荧光探测。同时,发光MOF膜,尤其是具有优异发光性能的、以稀土离子为发光中心的MOF膜的直接制备尚存在很大的挑战。针对以上问题,本文主要开展了金属-有机框架膜的多方法制备、后功能化修饰以及性能研究：采用原位溶剂热法分别在多孔阳极氧化铝膜、多孔α氧化铝陶瓷片以及Pt纳米颗粒修饰的硅片上制备连续密堆积的MOF多晶膜,同时利用“双铟源”的方法在ITO(氧化铟锡)玻璃上制备了MOF多晶膜；研究了孔洞表面带有羧酸官能团的MOFs粉末的气体吸附分离性能和该类MOF多晶膜的气体膜分离性能；采用稀土离子后功能化修饰的方法,获得以稀土离子为发光中心的发光MOF膜；研究了发光膜对硫醇蒸气、氧气等的荧光探测性能,以及MOFs中稀土离子与有机配体之间不同的传能过程对氧气探测性能的影响。采用溶剂热法合成了一种具有大孔结构的、孔洞表面羧酸基团修饰的MOFs材料In3O(OH)(H2O)2[BTC]2(MIL-100(In), BTC=1,3,5-苯三甲酸)。研究表明,由于MIL-100(In)孔洞表面含有羧酸基团,MOFs与极化率较高的甲烷间的相互作用强于极化率较低的氮气,室温下甲烷的吸附量约为氮气的2.5倍,甲烷／氮气的吸附选择性约为1.8。基于MIL-100(In)粉末的气体吸附分离性能的研究,采用原位溶剂热生长法在多孔阳极氧化铝膜和多孔a氧化铝陶瓷片上制备了连续密堆积的MIL-100(In)多晶膜,并研究活化后的MOF多晶膜对甲烷与氮气的气体膜分离性能。单组份气体渗透实验表明,以多孔阳极氧化铝膜为支撑的、约5μm厚的MOF多晶膜对甲烷和氮气的理想分离因子为3.38,甲烷渗透速率为0.81×10-6mol·m-2·s-1·Pa-1；以多孔α氧化铝片为支撑的、约5μm厚的MOF多晶膜,对甲烷和氮气的理想分离因子为2.75,甲烷的渗透速率为1.32×10-6mol·m-2·s-1·pa-1。甲烷和氮气与MOFs之间不同的相互作用强度使两种气体在MOFs中形成较大差异的表面扩散速率,最终致使MOF多晶膜具有优异的CH4/N2膜分离性能,为天然气和煤层气中的甲烷浓缩与提纯提供了新途径。同时,从气体在多孔膜中的表面扩散机理的角度去选择与制备孔洞表面具有官能团修饰的MOFs分离膜的策略为设计与制备具有优异分离性能的MOF膜提供了新的思路。采用溶剂热法在表面经Pt纳米颗粒修饰的硅片上成功制备了厚度范围为0.3～4.5μm的连续MIL-100(In)多晶膜。探索MIL-100(In)膜的生长过程和生长机理,推测MOFs在高缺陷和高表面能的Pt纳米颗粒表面更容易形核与生长,从而促进膜的生长与制备。采用稀土离子后功能化修饰的方法制备了以稀土离子为发光中心的MIL-100(In)(?)Ln3+(Ln=Eu、Tb、Dy和Sm)多晶膜。研究表明稀土离子与MOFs孔洞中的末去质子化的羧基发生配位作用,从而通过配体到稀土离子的传能作用,使稀土离子发光得到敏化。经活化的多孔MIL-100(In)(?)Eu3+发光膜对易挥发的1,2-乙二硫醇、正丁硫醇有较好的原位荧光探测性能。处于饱和蒸气浓度的1,2-乙二硫醇和正丁硫醇能够使MIL-100(In)=)Eu3+多晶膜分别发生约92%和94%的荧光淬灭。后修饰的方法为制备以稀土离子为发光中心的MOF膜提供了一种新的途径,解决了稀土MOFs难以制备为发光膜的难题。同时MOF发光膜能够直接实现原位荧光探测,排除非原位探测带来的干扰。采用“双铟源”方法,在表面覆盖氧化铟锡层的ITO玻璃上原位溶剂热生长制备了三种以In3+为金属离子的金属-有机框架膜,In12O(OH)12[(OH)4·(H2O)5][BTC]6(MIL-96(In))、[(CH3)2NH2][In3O(BTC)2(H2O)3]2[In3(BTC)4](CPM-5)和MIL-100(In)多晶膜。以MIL-96(In)多晶膜为例研究了其在ITO玻璃基板上的生长过程与生长机理,研究表明ITO玻璃表面的氧化铟锡层为MIL-96(In)在表面形核与生长提供了一种铟离子的来源,从而促进MOFs在表面的形核速率和生长速度。CPM-5为阴离子型金属-有机框架材料,孔洞中含有可自由移动的电平衡离子(CH3)2NH2+,因此实验采用离子交换后修饰的方法制备了含电平衡离子Tb3+的CPM-5(?)Tb3+发光膜。利用MIL-100(In)孔洞中含有未去质子化的羧基,采用后修饰的方法引入能与羧基发生螯合配位作用的Tb3+制备MIL-100(In)(?)Tb3+发光膜。基于MOFs的多孔性特点,研究了发光膜对氧气的探测性能,并考察了Tb3+在两种膜中不同的存在方式对氧气探测性能的影响。研究表明两种膜具有很好的氧气探测性能,膜的发光强度与氧气分压间的Sterm-Volmer曲线呈现很好的线性关系。以分子内能量转移的方式敏化稀土离子发光的MIL-100(In)(?)Tb3+多晶膜比以分子间能量转移的方式敏化稀土离子发光的CPM-5(?)Tb3+多晶膜具有更高的Sterm-Volmer淬灭常数KSV,即更高的灵敏度；并且由于MIL-100(In)(?)Tb3+比CPM-5(?)Tb3+具有更高的孔隙率,前者的膜具有更短的响应时间和恢复时间。MIL-100(In)(?)Tb3+多晶膜的氧气淬灭常数KSV最高约为14,对应的响应时间和恢复时间分别为4s和39s。稀土离子与有机配体间的能量传递过程对氧气探测性能的影响的研究为制备具有高灵敏度和快响应时间的MOF发光膜指引了方向。
[Abstract]:Metal-organic frameworks (MOFs), as a new type of porous inorganic organic hybrid crystalline material, has a great application prospect in the fields of gas storage and separation, luminescence, sensing and so on. It has been widely concerned. The membrane material has the characteristics of high efficiency, energy saving, economy and so on, and it can also extend the application scope. In some gaseous media, such as gas membrane separation, gas sensing, and so on. At present, the research of MOF film is still in the initial stage. There are few studies on the preparation and post functional modification of the continuous dense MOF membrane. The size difference between the pore size of gas molecules and the MOF membrane and the molecular weight difference between the gas subdivisions are sometimes difficult to be measured in size. A new way of separating gas from the interaction between gas molecules and the functional groups on the surface of the cavity surface of the MOF membrane becomes a new idea. The study of.MOFs materials in the field of fluorescence detection mainly focuses on the detection of small molecules, ions, and so on. The fluorescence detection of the gaseous medium is greatly limited. At the same time, the direct preparation of the luminescent MOF film, especially the MOF film with rare earth ions as the luminescent center, has great challenge.
In order to solve the above problems, this paper mainly carried out multi method preparation of metal organic frame membrane, post functionalized modification and performance study. In situ solvothermal method was used to prepare continuous dense MOF polycrystalline membrane on porous anodic alumina membrane, porous Al2O3 ceramic tablet and Pt nano particle modified silicon chip. The MOF polycrystalline membrane was prepared on ITO (indium tin oxide) glass by the method of indium source. The gas adsorption separation performance of the MOFs powder with carboxylic functional groups on the hole surface and the separation performance of the gas film in this kind of MOF polycrystalline membrane were studied. The luminescent MOF film with rare earth ions as the luminescent center was obtained by the method of functional modification after the rare earth ions. The detection performance of luminescence film for thiol vapor, oxygen and so on, as well as the influence of different energy transfer processes between rare earth ions and organic ligands in MOFs on the detection performance of oxygen are studied.
A kind of MOFs material In3O (OH) (MIL-100 (In), BTC=1,3,5- benzene three formic acid modified by the carboxylic acid group on the pore surface is synthesized by solvothermal method. The study shows that the interaction between the MIL-100 (In) hole surface contains carboxylic acid groups and the interaction between MOFs and high polar methane is stronger than that of low polarizability. The adsorption of methane at room temperature is about 2.5 times that of nitrogen, and the adsorption selectivity of methane / nitrogen is about 1.8. based on MIL-100 (In) powder. The in-situ solvent thermal growth method is used to prepare a continuous dense MIL-100 (In) polycrystalline membrane on porous anodic alumina membrane and porous a alumina ceramic. The performance of methane and nitrogen gas membrane was separated from the activated MOF polycrystalline membrane. The single component gas permeation experiment showed that the ideal separation factor of methane and nitrogen was 3.38 and the methane permeation rate was 0.81 x 10-6mol. M-2. S-1. Pa-1 with porous anodic alumina membrane supported by porous anodic alumina membrane, and the methane permeation rate was 0.81 x 10-6mol. M-2. S-1. Pa-1; porous Al2O3 was supported. The ideal separation factor of methane and nitrogen is 2.75, the ideal separation factor of methane and nitrogen is 2.75. The permeability rate of methane is 1.32 * 10-6mol. M-2. S-1. Pa-1. methane and the different interaction strength between nitrogen and MOFs, which makes the two different kinds of surface diffusion rate in MOFs, which eventually leads to the excellent CH4/N2 film of MOF polycrystalline membrane. The separation performance provides a new way for the concentration and purification of methane in natural gas and coalbed methane. At the same time, the strategy of selecting the MOFs separation membrane with functional group modification on the surface of the porous membrane from the surface diffusion mechanism of the gas in the porous membrane provides a new idea for the design and preparation of the MOF film with excellent separation performance.
Continuous MIL-100 (In) polycrystalline membrane with a thickness range of 0.3 to 4.5 u m was successfully prepared on the surface of Pt nanoparticles modified by solvothermal method. The growth process and growth mechanism of MIL-100 (In) films were explored. It is speculated that MOFs can be more easily nucleated and grown on the surface of Pt nanoparticles with high defects and high surface energy, thus promoting the growth of the membrane and the growth of the membrane. The polycrystalline films of MIL-100 (In) (?) (?) Ln3+ (Ln=Eu, Tb, Dy and Sm) with rare earth ions as the luminescent center were prepared by functional modification after rare earth ions. The study showed that the coordination of rare earth ions and the carboxylic groups of the terminal deprotonation in the pores of MOFs, through the transfer of the ligand to the rare earth ions, led to the luminescence of the rare earth ions. The activated porous MIL-100 (In) (?) Eu3+ luminescent film has a good in situ fluorescence detection performance for the volatile 1,2- B two thiol and n-butanol. The 1,2- two thiol and n-butanol at the saturated vapor concentration can make the MIL-100 (In) =) Eu3+ polycrystalline membrane about 92% and 94% fluorescence quenching respectively. The rare earth ions provide a new way for the MOF film of the luminescent center, which solves the difficult problem that the rare earth MOFs is difficult to prepare as a luminescent film. At the same time, the MOF luminescent film can directly detect the fluorescence in situ and eliminate the interference from the non in situ detection.
Three kinds of metal organic frame membranes, In12O (OH) 12[(OH) 4. (H2O) 5][BTC]6 (MIL-96 (In)), In12O (OH) 12[(OH) 4. (MIL-96) and polycrystalline membrane, are prepared by the "double indium source" method in situ solvothermal growth on the ITO glass covered with indium tin oxide layer. The growth process and growth mechanism on the ITO glass substrate have been studied. The study shows that the indium tin oxide layer on the surface of ITO glass is MIL-96 (In), which provides a source of indium ions in the surface nucleation and growth, thus promoting the nucleation rate and growth speed of MOFs on the surface of the MOFs as an anionic organic frame material and the hole in the hole. There is an electrically balanced ion (CH3) 2NH2+ that can be freely moved, so the CPM-5 (?) Tb3+ luminescence film of an electrically balanced ion Tb3+ is prepared by the method of post exchange modification. MIL-100 (In) Kong Dongzhong contains an unprotonated carboxyl group, and the post modification method is used to prepare MIL-100 (In) with a Tb3+ that can chelate the carboxyl group. Tb3+ luminescence film. Based on the characteristics of the porous properties of MOFs, the detection performance of the luminescent film on oxygen is studied, and the effect of different modes of existence of Tb3+ on the oxygen detection performance in the two kinds of membranes is investigated. The study shows that the two films have good oxygen detection performance, and the Sterm-Volmer curves between the luminescence intensity and the oxygen partial pressure of the membrane are very good. The MIL-100 (In) (?) Tb3+ polycrystalline membrane sensitized by the intramolecular energy transfer method has a higher Sterm-Volmer quenching constant KSV, or higher sensitivity, than the CPM-5 (?) Tb3+ polycrystalline membrane sensitized by the intermolecular energy transfer method; and because MIL-100 (In) Tb3+ is CPM-5 (?) Tb3+. With higher porosity, the former film has shorter response time and recovery time, the oxygen quenching constant KSV of.MIL-100 (In) Tb3+ polycrystalline membrane is about 14. The corresponding response time and recovery time are the study of the influence of the energy transfer process between the 4S and 39s. rare earth ions and the organic ligands on the oxygen detection performance. The MOF light-emitting film with high sensitivity and fast response time has guided the way.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TB383.2

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