Research progress on the substrate for metal-organic framework(MOF) membrane growth for separation

During the last decade, metal-organic frameworks(MOFs) have been applied in various fields due to their unique chemical and functional advantages. One of the widespread research hotspots is MOF-based membranes for separations, specifically continuous defect-free MOF membranes, which are usually grown on porous substrates. The substrate not only serves as the MOF layer support but also has a great influence on the membrane fabrication process and the final separation performance of the resultant membrane. In this review, we mainly introduce the progress focused on the substrates for MOF membranes fabrication. The substrate modifications and seeding methods aimed at synthesizing highquality MOF membranes are also summarized systematically.

Long-term durable anion exchange membranes based on imidazole-functionalized poly(ether ether ketone)incorporating cationic metal-organic framework

In this work,poly(ether ether ketone)(PEEK)was synthesized by direct polycondensation reaction.Subsequently,PEEK was functionalized by 1-vinylimidazole to prepare the polymer matrix(Im-PEEK).Cationic UiO-66-NH_(2) metal-organic frameworks(C-MOF)were synthesized as fillers.The structure of the C-MOF and the morphology of the membranes were verified by Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD)and field emission scanning electron microscopy(FE-SEM).The prepared hybrid membranes exhibited excellent alkali stability,among which Im-PEEK/C-MOF^(-1)%could retain 89.2%of the conductivity compared to the original membrane after immersing in 1 mol L^(-1) NaOH solution for 320 h at 60℃.In addition,the ionic conductivity of Im-PEEK/C-MOF^(-1)%was 73 mS cm^(-1) at 80℃,which was higher than that of pure Im-PEEK under the same condition(44.3 mS cm^(-1) at 80℃).The results showed that the hybrid membranes have great potential for application in the field of anion exchange membranes.

Self-assembled Cyclodextrin Metal-Organic Frameworks on Graphene Oxide as Filter Membrane for Tracelevel Naringin Pre-enrichment before Analysis

A green,renewable composite was designed and fabricated based on self-assembly of cyclodextrin metal-organic framework(CD-MOF)on graphene oxide(GO).Then,the GO@CD-MOF was embedded in 0.45μm PTFE membrane to produce a dual-functional membrane which could carry out sample enrichment by capturing naringin molecules.The membrane filter was further improved by investigating the effects of the experimental parameters including amount of GO@CD-MOF,enrichment time and elution solvent on enrichment efficiency of naringin.Further,the present method had been successfully applied to citrus sample and obtained satisfied recovery value(79.7%-100.3%).Moreover,the extraction of naringin can be achieved for 2 min,and GO@CD-MOF loaded membrane can be reused at least for 5 times.The results demonstrate that the fabrication of the novel filter membrane based on GO@CD-MOF is a fast,simple and reliable,and possesses great potential in the determination of naringin from real samples by dual-function of separation and enrichment.

Photophysics of metal-organic frameworks:A brief overview

Metal-organic frameworks(MOFs),which are self-assembled porous coordination materials,have garnered considerable attention in the fields of optoelectronics,photovoltaic,photochemistry,and photocatalysis due to their diverse structures and excellent tunability.However,the performance of MOF-based optoelectronic applications currently falls short of the industry benchmark.To enhance the performance of MOF materials,it is imperative to undertake comprehensive investigations aimed at gaining a deeper understanding of photophysics and sequentially optimizing properties related to photocarrier transport,recombination,interaction,and transfer.By utilizing femtosecond laser pulses to excite MOFs,time-resolved optical spectroscopy offers a means to observe and characterize these ultrafast microscopic processes.This approach adds the time coordinate as a novel dimension for comprehending the interaction between light and MOFs.Accordingly,this review provides a comprehensive overview of the recent advancements in the photophysics of MOFs and additionally outlines potential avenues for exploring the time domain in the investigation of MOFs.

Insights into microscopic fabrication, macroscopic forms and biomedical applications of alginate composite gel containing metal-organic frameworks

Overcoming the poor physicochemical properties of pure alginate gel and the inherent shortcomings of pure metal-organic framework(MOF),alginate/MOF composite gel has captured the interest of many researchers as a tunable platform with high stability,controllable pore structure,and enhanced biological activity.Interestingly,different fromthe traditional organic or inorganic nanofillers physically trapped or chemically linked within neTtworks,MOFs crystals can not only be dispersed by crosslinking polymerization,but also support self-assembly in-situ under the help of chelating cations with alginate.The latter is influenced by multiple factors and may involve some complex mechanisms of action,which is also a topic discussed deeply in this article while summarizing different preparation routes.Furthermore,various physical and chemical levels of improvement strategies and availablemacroforms are summarized oriented towards obtaining composite gel with ideal performance.Finally,the application status of this composite system in drug delivery,wound healing and other biomedical fields is further discussed.And the current limitations and future development directions are shed light simultaneously,which may provide guidance for the vigorous development of these composite systems.

Metal-Organic Framework Materials for Electrochemical Supercapacitors

Exploring new materials with high stability and capacity is full of challenges in sustainable energy conversion and storage systems.Metal-organic frameworks(MOFs),as a new type of porous material,show the advantages of large specific surface area,high porosity,low density,and adjustable pore size,exhibiting a broad application prospect in the field of electrocatalytic reactions,batteries,particularly in the field of supercapacitors.This comprehensive review outlines the recent progress in synthetic methods and electrochemical performances of MOF materials,as well as their applications in supercapacitors.Additionally,the superiorities of MOFs-related materials are highlighted,while major challenges or opportunities for future research on them for electrochemical supercapacitors have been discussed and displayed,along with extensive experimental experiences.

Design and synthesis of Al-MOF/PPSU mixed matrix membrane with pollution resistance

To enhance the performance of the polyphenylene sulfone(PPSU) membrane,a novel mixed matrix membrane with hydrophilicity and antifouling properties was prepared.Using PPSU as the ba sic membrane material,polyvinyl pyrrolidone(PVP) as the porogen,N-Methyl pyrrolidone(NMP) as the solvent,and MOF-CAU-1(Al_(4)(OH)_(2)(OCH_(3))_4(H_2 N-BDC)_(3)·xH_(2) O) as the filler,PPSU/CAU-1 mixed matrix membrane(MMM) was prepared by an immersion precipitation and phase transformation technique.By changing the amount of MOF-CAU-1,the properties and performance of the MMM membrane were investigated in terms of hydrophilicity,pore morphology,surface roughness,and dye removal.The results show that the highest pure water flux of the mixed reached 47.9 L·m^(-2)·h^(-1), when the CAU-1 addition amount was 1.0 wt%, which was 23% higher than that of the pure PPSU membrane.Both the rejection rate and the antifouling performance of the MMM membrane also noticeably improved.

An Overview of Metal-Organic Frameworks for Green Chemical Engineering

Given the current global energy and environmental issues resulting from the fast pace of industrialization,the discovery of new functional materials has become increasingly imperative in order to advance science and technology and address the associated challenges.The boom in metal–organic frameworks(MOFs)and MOF-derived materials in recent years has stimulated profound interest in exploring their structures and applications.The preparation,characterization,and processing of MOF materials are the basis of their full engagement in industrial implementation.With intensive research in these topics,it is time to promote the practical utilization of MOFs on an industrial scale,such as for green chemical engineering,by taking advantage of their superior functions.Many famous MOFs have already demonstrated superiority over traditional materials in solving real-world problems.This review starts with the basic concept of MOF chemistry and ends with a discussion of the industrial production and exploitation of MOFs in several fields.Its goal is to provide a general scope of application to inspire MOF researchers to convert their focus on academic research to one on practical applications.After the obstacles of cost,scale-up preparation,processability,and stability have been overcome,MOFs and MOF-based devices will gradually enter the factory,become a part of our daily lives,and help to create a future based on green production and green living.

An efficient strategy for the preparation of MIL-53(Al)-NH_(2)membranes with high ion selectivity and desalination performance

The efficient extraction of sodium(Na^(+))and lithium(Li^(+))from seawater and salt lakes is increasingly demanding due to their great application value in chemical industries.However,coexisting cations such as divalent calcium(Ca^(2+))and magnesium(Mg^(2+))ions are at the subnanometer scale in diameter,similar to target monovalent ions,making ion separation a great challenge.Here,we propose a simple and fast secondary growth method for the preparation of MIL-53(Al)-NH_(2)membranes on the surface of anodic aluminum oxide.Such membranes contain angstrom-scale(~7Å)channels for the entrance of small monovalent ions and water molecules,endowing the selectivities for monovalent cations over divalent cations and water over salt molecules.The resulting high-connectivity MIL-53(Al)-NH_(2)membranes exhibit excellent ion separation performance(a selectivity of 121.42 for Na^(+)/Ca^(2+)and 93.81 for Li^(+)/Mg^(2+))and desalination performance(a water/salt selectivity of up to 5196).This work highlights metal–organic framework membranes as potential candidates for realizing ion separation and desalination in liquid treatment.

Novel in-capsule synthesis of metal-organic framework for innovative carbon dioxide capture system

Metal-Organic Frameworks(MOFs)have been developed as solid sorbents for CO_(2) capture applications and their properties can be controlled by tuning the chemical blocks of their crystalline units.A number of MOFs(e.g.,HKUST-1)have been developed but the question remains how to deploy them for gas-solid contact.Unfortunately,the direct use of MOFs as nanocrystals would lead to serious problems and risks.Here,for the first time,we report a novel MOF-based hybrid sorbent that is produced via an innovative in-situ microencapsulated synthesis.Using a custom-made double capillary microfluidic assembly,double emulsions of the MOF precursor solutions and UV-curable silicone shell fluid are produced.Subsequently,HKUST-1 MOF is successfully synthesized within the droplets enclosed in the gas permeable microcapsules.The developed MOF-bearing microcapsules uniquely allow the deployment of functional nanocrystals without the challenge of handling ultrafine particles,and further,can selectively reject undesired compounds to protect encapsulated MOFs.

A Three-dimensional Porous Metal-organic Framework Based on Cyano Unit and 1,4-Bis(1,2,4-triazol-1-yl)butane(btb):{[Cu_8(btb)_2(CN)_8].3H_2O}_n

The title coordination polymer 1,{[Cu8（btb）2（CN）8].3H2O}n（btb = 1,4-bis（1,2,4-triazol-1-yl）butane）,has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction.Complex 1 crystallizes in monoclinic,space group C2/c with a = 1.2938（3）,b = 1.9422（5）,c = 0.9406（2） nm,β = 121.891（4）°,V = 2.0066（9） nm3,C24H30Cu8N20O3,Mr = 1155.00,Dc = 1.912 g/cm3,μ（MoKα） = 4.209 mm？1,F（000） = 1140,GOF = 1.184,Z = 2,the final R = 0.0634 and wR = 0.1503 for I 2σ（I）.In complex 1,one-dimensional CuCN zigzag chains are linked by triazolyl groups of btb ligands to form two-dimensional networks,which are further bridged by 1,4-butyl moieties of btb ligands to fabricate a three-dimensional order framework,in which one-dimensional ellipsoid-like channels are observed.

Equilibrium,Kinetics and Thermodynamics of the Adsorption of Methylene Blue onto a Metal-Organic Frameworks Material,Copper Coordination Polymer with Dithiooxamide

The equilibrium, kinetics and thermodynamics of the adsorption of methylene blue( MB) from aqueous solution onto copper coordination polymer with dithiooxamide( H2dtoaCu),one of the metal-organic frameworks( MOFs),were investigated in a batch adsorption system as a function of initial pH, adsorbent concentration, contact time, initial dye concentration, and temperature. The Langmuir, Freundlich, and DubininRadushkevich( D-R) isotherm models were used for modeling the adsorption equilibrium. It was found that Langmuir model yielded a much better fit than the Freundlich model under different temperatures. The maximum monolayer adsorption capacities of MB were 192. 98,229. 86,and 297. 38 mg /g at 298,308,and 318 K,respectively. The calculated mean adsorption energy( 8. 26-11. 04 kJ /mol) using D-R model indicated that the adsorption process might take place by chemical adsorption mechanism.Otherwise,the kinetic studies revealed that the adsorption process could be well explained by pseudo-second-order rate kinetics and intraparticle diffusion was not the rate-limiting step.Thermodynamic studies indicated that this system was feasible,spontaneous,and endothermic process. Based on these studies,H2dtoaCu can be considered as a potential adsorbent for the removal of MB from aqueous solution.

Quasi-solid electrolyte membranes with percolated metal–organic frameworks for practical lithium-metal batteries

High-energy Li-metal batteries (LMBs) suffer from short cycle life and safety issues due to severe parasitic reactions and dendrite growth of Li metal anode (LMA) in liquid electrolytes [1–3].It is generally believed that replacing liquid electrolytes with solidstate electrolytes (SSEs) would be a feasible approach for practical LMBs [4,5]. Conventional SSEs including ceramic and polymer electrolytes have been studied for decades.

Novel Metal-organic Framework Compound Pb(C_5H_4NCOO)_2 Showing One-dimensional Channel Defined as Four Leads and Four Nicotinic Acids

A novel metal-organic framework（MOF） compound of Pb（C5H4NCOO）2 was hydrothermally synthesized and structurally determined by X-ray single-crystal diffraction. The data of unit cell： orthorhombic space group Pccn, a=1.0325（2） nm, b=1.3597（3） nm, c=0.8499（2） nm, V=1.1931（4） nm^3, Z=4, Dc=2.513 g/cm^3, R1=0.047 were obtained on the basis of 1365 reflections with Fo〉2σ（Fo）. PbN2O6 polyhedron adopts the distorted cubic configuration which is assigned to the holodirected geometry. These PbN2O6 polyhedra can form the zigzag chain by edge-sharing mode along（001） direction. Pb atom is connected by six nicotinic acid molecules, leading neutral 3D metal-organic framework with a channel defined by four Pb atoms and four nicotinic acid molecules.

Regulatable pervaporation performance of Zn-MOFs/polydimethylsiloxane mixed matrix pervaporation membranes

Pervaporation(PV)is an emerging separation technique for liquid mixture.Mixed matrix membranes(MMMs)often demonstrate trade-off relationship between separation factor and flux.In this study,by changing the organic linkers(2-methyl imidazolate,imidazole-2-carboxaldehyde,2-ethyl imidazolate),ZIF-8,ZIF-90 and MAF-6 were prepared and filled in polydimethylsiloxane(PDMS)membranes for dealcoholization of 5%(mass)n-butanol solution,and the membranes properties and pervaporation performances were adjusted.Compared with the pure PDMS membrane,the addition of ZIF-8 resulted in a 9%increase in flux(1136 g·m^(-2)·h^(-1))and a 22.5%increase in separation factor(28.3),displaying antitrade-off effect.For the MAF-6/PDMS MMMs(2.0%mass loading),the pervaporation separation index(PSI)and separation factor were 32347 g·m^(-2)·h^(-1) and 58.6 respectively(increased by 34%and 154%in contrast with that of the pure PDMS membrane),and the corresponding permeation flux was 552 g·m^(-2)·h^(-1),presenting great potential in the removal butanol from water.It was deduced that the large aperture size combined with moderate hydrophobicity of metal–organic frameworks(MOFs)favor the concurrent increase in permeability and selectivity.

Nanoscale Metal-Organic Frameworks:Stimulus-Response and Applications

Metal-organic frameworks(MOFs),a crystalline porous material with a periodic net-work structure formed by the self-assembly of transition metal ions and organic ligands,have been widely applied in various fields due to their rich composition and structural diversity.Among vari-ous types of MOFs,stimuli-responsive MOFs have gained increasing attention in recent years,because of their broad application in the field of physics,biology,and chemistry.In this review,we analyzed and classified the mechanism of stimulus-response MOFs(pH response,glucose response,GSH response,light response,temperature response)and their applications in drug delivery,adsorption and luminescence functions,magnetization and catalysis functions,probe and sensor.

Immobilization of a Metal-Organic Framework on a Nanofiber Membrane as Artificial Platelets for Efficient Hemostasis

Medical hemostatic gauze is one of the most common agents for bleeding management used in pre-hospital care and clinical treatment.An ideal hemostat requires the features including fast coagulation ability,high biocompatibility and low cost,which is difficult to be achieved simultaneously.Herein,we reported a chemical immobilization method to uniformly anchor the zeolitic imidazolate framework(ZIF-8)nanoparticles on polyvinyl alcohol(PVA)membrane,which dramatically accelerated the in vivo conversion process of prothrombin to thrombin,achieving a short hemostasis time around 60 s with a low amount of blood loss of 23 mg.Later,the hemostatic mechanism was unveiled by two pathways involving the activation of platelets and the conversion of prothrombin,indicating that this ZIF-8-based membrane works in a similar way to natural platelet-based physiological processes.More importantly,the convenient manufacturing and excellent biocompatibility of ZIF-8-based membrane provide a practical candidate hemostat for clinical bleeding management.

金属有机骨架(MOFs)基复合质子交换膜的研究进展

近年来,金属有机骨架(MOFs)材料由于具有超大的比表面积和丰富的孔道结构,作为一种新型的质子导体在质子交换膜中的应用受到越来越多的关注。随着研究的不断深入,为进一步提升MOFs复合质子交换膜的各项性能,MOFs材料在质子交换膜中的物理形态逐渐由颗粒状向连续相发展,MOFs材料的组分也呈现出由单一组分到双组分的发展态势。本文以质子交换膜中MOFs材料的物理形态为主线,将其划分为MOFs晶体/聚合物质子交换膜、第三相增强MOFs/聚合物复合质子交换膜和MOFs纳米纤维/聚合物复合质子交换膜,全面综述了MOFs材料在质子交换膜中的研究进展,并对MOFs复合质子交换膜的发展方向进行了展望。

Hemoglobin integrated red blood cell membrane-coated metalorganic framework nano-platform for improving the self-adaptive blood glucose management

Diabetes,a prevalent chronic metabolic disorder,often leads to severe complications.Currently,existing treatment methods may pose life-threatening risks due to poor patient compliance and inaccurate dosing of subcutaneous insulin injections.Hence,a biomimetic red blood cell(RBC)membrane-coated glucose-responsive nanoplatform is developed for controlling insulin release.Functionalizing nanoplatforms with RBC membrane can prolong the half-life of nano-formulation in vivo mediated by the biomimetic immune escape.Simultaneously,the cascade catalytic effect of glucose oxidase(GOx)encapsulated in metal-organic frameworks(MOFs)and hemoglobin(Hb)in the RBC membrane are able to not only facilitate glucose-responsive insulin release,but also eliminate the detrimental by-product hydrogen peroxide(H_(2)O_(2))resulting from the Hb mediated H_(2)O_(2)scavenging.Both in vitro and in vivo studies have demonstrated the favorable glucose-responsive performances of this advanced nano-platform with a single intravenous injection maintaining blood glucose balance in Type 1 Diabetes(T1D)mice for an extended duration without the hypoglycemia risk.Therefore,this biomimetic insulin delivery system is poised to function as a strategy for the intravenous insulin administration,offering a promising drug candidate for the self-adaptive long-term T1D treatment.

Green ionic metal-organic frameworks as nanocatalysts for CO_(2)fixation

Co,Ni,and Zn iso-reticular coordination polymers of 2,5-dihydroxyterphthalic acid(H_(2)dot)can be rapidly obtained under room temperature and aqueous conditions using either sodium or ammonium hydroxide as the bases to deprotonate the linker.The use of metal bromides and tetrabutylammonium hydroxide(TBAOH)as the base allows the green synthesis of ionic metal-organic frameworks(MOFs),characterized by X-ray diffraction(XRD),Fourier transform infrared(FTIR),scanning electron microscopy(SEM),thermo gravimetric analysis(TGA),H-nuclear magnetic resonance(NMR),elemental analysis,and X-ray photoelectron spectroscopy(XPS),and employed in the pressure,solvent,and additive-free CO_(2)fixation to epoxides by its cycloaddition to epichlorohydrin,exhibiting a cooperative behavior between the MOF and the ionic liquid formed within the framework,achieving TONs of the confined tetrabutylammonium bromide(TBABr)up to 700.