Molecularly imprinted polymer based on metal-organic frameworks: synthesis and application on determination of dibutyl phthalate

ABSTRACT

The molecular surface imprinted graft copolymer of metal-organic framework MOF-5 with methacrylic acid were prepared by free radical polymerization with dibutyl phthalate as the template molecule using initiator of azobisisobutyronitrile as adsorption system. The prepared MIPs@MOF-5 were characterized by fourier transform infrared spectroscopy, scanning electron microscopy, Brunner?Emmet?Teller measurements, adsorption isotherms, kinetics and selectivity experiments, which showed higher specificity, sensitivity, stability, and better adsorption performance. The results suggested that MIPs@MOF-5 had two sites of adsorption behavior and can recognize sensitively and selectively the template molecules. Moreover, the MIPs@MOF-5 was successfully applied to the analysis of tap water sample.     

Multilevel screening of computation-ready,experimental metal-organic frameworks for natural gas purification

In this study, traditional Monte Carlo simulation and density functional theory-based structural optimization methods were combined to screen computation-ready experimental metal-organic framework (MOF) database for the application of natural gas purification. Our results show that about half of the good performing computation-ready experimental MOF structures displayed various degrees of deformation (even collapse) after the structure optimization. This phenomenon attributed to the strong attraction of unsaturated metals which attract nearby organic components. For some materials with deformation, unsaturated metals form new bonds with the adjacent organic linkers creating distortions that would be unrealistic in the experimental materials. For the remaining relatively stable materials whose structural characteristics did not change too much, we further studied the adsorption performance of their optimized structures. Finally, 12 good-performing MOF materials with high stability were found which could greatly improve the possibility for constructing robust MOFs that could hold open metal sites by experiments.     

The study of vapour phase hydrogen peroxide decontamination process as a potential method for degradation of organic pollutants

BACKGROUND: The work is focused on the application of vapour phase hydrogen peroxide (VPHP) as a highly promising and effective decontamination technique. The aim of this work was to assess the use of this validated technique for the removal of chemicals from contaminated surfaces and examine the impact of key parameters on the course of the decontamination process. RESULTS: Unique sophisticated laboratory equipment was developed to test the effect of VPHP on chemical substances. It was used for the evaluation of the role of crucial parameters such as the relative humidity, condensation and synergistic effect of UV radiation on the VPHP agent efficiency on a model compound (vanillin) degradation. The degradation rate of the model substance was notably affected by all these factors. CONCLUSION: VPHP could be used for an efficient decomposition of vanillin. The course of the decontamination process was strongly influenced by condensation (showing a substantial difference between ‘wet’ and ‘dry’ processes) and the synergistic effect of UV radiation influencing the reaction rate and degree of decomposition. Copyright © 2010 Society of Chemical Industry     

锆基金属有机骨架材料用于氨吸附性能的研究

近年来,金属有机骨架材料（MOF）在气体吸附和储存领域得到了迅速发展,但由于结构的不稳定性,其在强腐蚀性气体氨（NH₃）的吸附方面并不令人满意。考虑到NH₃是唯一的无碳排放的氢能源载体,开发高效的储氨技术来载氢是有效的降低二氧化碳排放的手段。利用MOF材料具有的高比表面积和结构多样的特性,在NH₃的吸附和储存方面具有广阔的应用前景。而NH₃具有孤对电子,会攻击金属与配体之间形成的配位键,使MOF材料的结构遭到破坏。锆基金属有机骨架材料是公认结构稳定性较好的MOF材料,但其是否能胜任干燥NH₃及含水条件下的稳定性仍未深入考察,由此需探究该系列材料在NH₃吸附领域的适用性。在此,通过实验和计算模拟研究锆基系列的金属有机骨架UiO-66、NU-1000、MOF-801和 MOF-808的结构特征、稳定性和NH₃吸附性能。结果表明,UiO-66、NU-1000和MOF-808在纯NH₃环境下的稳定性较好,并且显示出高吸附量且可循环的氨吸附性能（13.04、6.38、9.65 mmol/g）。受限于水和氨对结构的协同破坏作用,NU-1000和MOF-801的结构均不能维持,而UiO-66和MOF-808的结构非常稳定,无论在干燥NH₃环境及含水NH₃环境下均能胜任而应用于NH₃吸附和储存。     

面向生物甲烷分离的不同金属配位金属-有机骨架材料的分子设计

采用巨正则Monte Carlo法（GCMC）,对CH₄ /CO₂混合气体体系基于金属-有机骨架材料（MOFs）的吸附分离进行了模拟研究。吸附分离材料涉及3个系列（M-MOF-74、M-MIL-53和[M（atz）（bdc）_0.5]）（M=Mg,Co,Ni,Zn,Al,Cr）不同金属配位的8种MOF材料。研究表明,Mg-MOF-74的CO₂吸附性能在高压下优于其他材料;在低压时,拥有大量氨基官能团的[Zn（atz）（bdc）_0.5]和[Co（atz）（bdc）_0.5]材料有更高效的CO₂分离性能。通过径向分布函数和CO₂吸附构型快照重叠图进一步分析发现,各个系列材料不同金属配位对CO₂吸附构型的影响造成了材料吸附分离性能有较大的不同。研究结果能够为实验上设计和开发新型高效CO₂和CH₄吸附分离MOFs材料提供启发。     

Sound absorption characteristics of polymer microparticles

A sound absorption material composed of polymer microparticles and polyurethane (PU) foam with certain geometry cavum has been developed. Its sound‐absorbing characteristic was investigated in the impedance tube, according to transfer function method. Measurements show that polymer microparticles have remarkable effect on the absorption performance of the composite material because of their microstructures and features. Several models established for acoustic properties have been adopted to fit the experimental data. The results show that these models fail to predict accurately the acoustic properties of the materials. The sound energy attenuation in polymer microparticles material may most likely consist of two parts, viscous attenuation of air inside the pores and the friction energy caused by the oscillation of polymer particles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2673–2679, 2006     

溶剂化效应对金属-有机骨架材料界面微环境催化性能的影响

金属-有机骨架材料（metal-organic frameworks,MOFs）的纳微结构可根据特定需求进行功能化调控,有望成为良好的工业催化材料。由于溶剂环境可对其界面微环境及催化性能产生较大影响,因此研究溶剂化效应对于MOF材料的影响具有重要的意义。以Cu-BTC和MOP-15两种典型MOF材料作为研究对象,采用密度泛函理论与COSMO溶剂模型相结合的方法,考察了溶剂效应对材料几何结构与电子稳定性的影响,并研究了不同溶剂对其Lewis酸性的影响。结果表明,溶剂环境可以使材料中的电子从不饱和配位金属处转移到有机配体上,进而使材料具有更强的Lewis酸性,并且电负性较大有机配体构成的MOF材料,受溶剂效应的影响更加显著。本工作将有助于深入理解溶剂化对调控MOF材料液相催化活性的影响。     

Residues of organic contaminants in beeswax

Residues of the varroacides amitraz, chlordimeform, chlorfenvinphos, bromopropylate, coumaphos, tetradifon, acrinathrin, and fluvalinate, the organic microcontaminants 4,4'‐DDE, 4,4'‐TDE, PCB 153 and PCB 180, and the lipophilic pesticides lindane, chlorpyrifos and endosulfan have been determined by GC/MS in 52 beeswax samples. Recoveries on spiked samples ranged from 93 to 108% and determination limits varied from 4 to 65 µg/kg. Lindane (0.042–0.29 mg/kg), chlorfenvinphos (0.16–7.62 mg/kg), 4,4'‐TDE (0.20 mg/kg), bromopropylate (0.041–0.12 mg/kg), tetradifon (0.032–0.58 mg/kg), acrinathrin (0.058–0.59 mg/kg), coumaphos (0.27–0.38 mg/kg), fluvalinate (0.064–5.10 mg/kg), endosulfan sulfate (0.12–0.37 mg/kg) and 3‐phenoxybenzaldehyde, a degradation product of fluvalinate and acrinathrin (0.080–1.47 mg/kg), were the compounds detected in beeswax. Foundation beeswax sheets contained higher contaminant concentrations and a greater diversity of compounds in relation to comb beeswaxes. Repeated melting in boiling water of purified beeswax spiked with the contaminants did not substantially modify the content of most of the contaminants in beeswax, except for amitraz and chlordimeform, showing that the contaminants are stable and remain practically unchanged in the purified beeswax.     

金属有机框架材料的水稳定性及吸水应用进展

水蒸气广泛存在于空气和工业气体中,收集利用或去除水蒸气都需要利用高吸水储水的吸附剂。金属有机框架材料(metal-organic frameworks,MOFs)作为一种具有高孔隙率、高比表面积的新型多孔材料,同时具备网状结构和孔径可控调节的特性,被广泛应用于吸附、分离、催化、过滤等多个领域。将MOFs应用于水吸附领域不仅要求MOFs具备较高的水稳定性,还需要具备亲水和吸附-脱附循环能力。本文综述了水稳定性MOFs的基本组成,基于皮尔森软硬酸碱理论的设计原则,水吸附行为的影响因素以及空气集水、气体除湿等应用领域的进展,以饱和吸湿量为参考罗列了13种水吸附MOFs及其衍生物的物理参数。最后总结了水吸附MOFs在合成机理、批量制备和应用领域存在的问题,并对应提出了解决思路,期望为MOFs在水吸附应用的研究方向提供有价值的参考。     

Stabilization of immiscible polymer blends using structure directing metal organic frameworks (MOFs)

We have developed a novel approach for compatibilizing immiscible polymer blends using metal organic frameworks (MOFs). For the first time we demonstrated that the droplet diameter of the dispersed phase in a 1:1 immiscible polymer blend composed of 6FDA-DAM:DABA [copolymer of 4,4-hexafluoroisopropylidene diphthalic anhydride (6FDA), 2,4,6-trimethyl-1,3-phenylenediamine and 3,5-diaminobenzoic acid (DABA)], and polybenzimidazole (PBI), is dramatically reduced obtaining a uniform microstructure with the incorporation of as low as 5% (w/w) of the zeolitic imidazolate framework-8 (ZIF-8). This indicates a large improvement in the compatibility of the immiscible polymers with the inclusion of ZIF-8. As the ZIF-8 loading was further increased to 10% (w/w), the droplet diameter further decreased resulting in even higher compatibility. The compatibilizing effect can be attributed to a reduction in the interfacial energy of the immiscible polymers due to the interfacial localization of ZIF-8. This MOF based compatibilization of immiscible polymer blends can open up opportunities for the combination of different properties of polymers in membrane-based separations and in more applications.     

钛基金属-有机框架材料的改性及其催化性能研究

使用双氧水在一定温度下对钛基金属-有机框架材料NH₂-MIL-125进行改性处理，制备得到一系列材料，系统地研究了改性方法及改性条件对材料性能的影响。结果表明，经改性处理后的材料，在可见光催化苯甲醇氧化反应中的催化速率有显著提高；同时，改性过程中的双氧水用量及改性温度对材料的结构、性质和光催化性能都有十分重要的影响。当双氧水为10 ml、改性温度为50℃时，改性材料具有优异的催化活性、选择性以及良好的稳定性，其催化速率与NH₂-MIL-125相比提高近6倍。     

Postsynthetic acid modification of amino-tagged metal-organic frameworks: Structure-functionrelationship for catalytic 5-hydroxymethylfurfural synthesis

Developing an efficient and selective catalyst for the dehydration of fructose to 5-hydroxymethylfurfural(HMF) is significant for biomass conversion. Herein, a metal-organic framework(MOF) with acidity and strong hydrophobicity is first reported by the condensation of amino-tagged MOFs with mercapto carboxylic acids and subsequent oxidation. The hydrophobic acidic MOFs possess acid densities ranging from 0.2-1.0 mmol·g^-1, H₂O contact angles of 114°-125°, and specific surfac...     

催化剂制备与研究热解温度对自模板法制备纳米催化剂催化活性的影响

金属有机骨架材料(MOFs)作为典型的自模板材料已被广泛应用于催化、电化学和吸附等领域。采用水热法合成两种含氮的Co-Ni-MOF和Co-Cu-MOF材料,并以两种材料为模板剂,在不同温度热解制备Co-Ni@NC和Co-Cu@NC纳米催化剂。将两种纳米催化剂用于乙基苯选择性氧化制备苯乙酮反应, 研究热解温度对催化剂催化活性的影响。结果表明,随着热解温度升高,催化活性逐渐增强,当热解温度达到900 ℃时,催化活性最高,苯乙酮收率为98%~99%,催化剂还表现出较好的重复使用性能。     

光合细菌降解有机污染物的研究进展

利用微生物降解有机污染物是环境工程研究的热点之一。光合细菌(PSB)以其特有的生理特性和降解多种有机污染物的能力，日益受到了人们的重视。综述了光合细菌降解较复杂的有机污染物的种类、降解机理、有关的降解酶类和降解性质粒等方面的研究工作，为进一步扩大光合细菌实际应用展示了广阔的前景。     

金属-有机骨架材料在气体膜分离中的研究进展

金属-有机骨架材料(metal-organic frameworks,MOF)由于具有高比表面积、大孔隙率、功能性孔道结构以及种类多样性等特征,在储气、分离、催化、载药和光学等领域受到重视。其中,制备纯MOF膜或基于MOF的混合基质膜(mixed matrix membranes,MMMs)并用于气体分离,被认为具有潜在的应用前景。目前为止,实验合成的MOF材料种类已有两万种,为了快速筛选出合适的MOF材料作为膜材料,计算化学的方法可以极大地缩减MOF膜的研究周期,并有助于指导实验合成高效膜分离材料。本文分别从计算和实验两方面介绍了MOF膜在气体分离中的研究进展,分析表明,MOF膜的研究总体上向功能性更强、稳定性更高的方向发展,但是利用计算方法建立MOF膜的构效关系还存在一定的难度。因此,建立MOF膜的结构与性能表征的新概念、新方法,并利用MOF膜的结构-性能关系指导实验合成高稳定性、低成本的膜材料将是未来MOF膜的发展方向。     

Acid-base properties and catalytic activity of metal-organic frameworks: A view from spectroscopic and semiempirical methods

This article summarizes several approaches for understanding the catalytic chemistry and “structure-surface acidity-reactivity” relationships in a multiplicity of catalytic applications of a continually increasing assemblage of metal-organic frameworks (MOFs) structures. The various spectroscopic techniques for acid-base characterization of MOFs are reviewed. The experimental requirements and the type and nature of probe molecules available are also discussed. Special emphasis is given to the revealing of the surface acid-base effect on the catalytic performance of MOFs.     

Membrane functionalization using bisamide-based organic frameworks for molecular weight cutoff reduction

Functional polymers or copolymers have been added to separations membranes by incorporating them in the membrane dope prior to casting, by in situ polymerization, and by postsynthesis surface modification of existing membranes. Here, a postsynthesis membrane functionalization that targeted decreasing the molecular weight cutoff (MWCO) and increasing the hydrophilicity without significantly decreasing the operating flux was studied. Hybrid bisamide molecules with added amine and carboxylic acid functionalities as end groups were synthesized to form a selective layer on membrane surface via covalent attachment to the membrane. Fourier transform infrared spectroscopy analysis showed the functional groups corresponding to bisamide molecules were present on modified membranes. Furthermore, modified membranes displayed MWCO of 400 Da as compared to 1000 Da MWCO of unmodified membranes, along with an increase in the hydrophilicity of modified membranes. Modified membranes showed an improvement in divalent salt rejection and percent flux recovered after reverse-flow filtration as compared to unmodified membranes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48327.     

金属有机骨架材料在吸附分离CH_4/N_2中的研究进展

简单介绍了金属有机骨架材料的发展,主要从甲烷选择型MOF吸附剂、氮气选择型MOF吸附剂2个方面综述了金属有机骨架材料在CH4/N2分离中的研究进展,并对MOFs吸附剂与传统吸附剂的CH4/N2分离性能进行了比较,同时展望了MOFs吸附剂在低品质煤层气脱N2过程的应用前景。     

溴改性金属有机骨架的合成及其对单质汞吸附

采用溶剂热法制备了溴改性的金属有机骨架(metal organic framework,MOF),通过模拟烟气动态吸附方法对材料单质汞(Hg⁰)吸附性能进行研究。利用X射线衍射(XRD)、X射线光电子能谱(XPS)、综合吸附仪对晶体结构、形貌和组分进行表征。结果表明改性后晶体结构不变,比表面积、孔容下降,溴以共价键固定在材料中。改性前和改性后材料对Hg⁰的吸附效率都有随温度升高而增加趋势。模拟烟气反应床吸附实验证明240℃条件下,溴改性MOF10h内吸附效率高于95%,同等实验条件下,非改性MOF以及传统活性炭吸附剂吸附汞5h后效率低于75%。