Practical MOF Nanoarchitectonics: New Strategies for Enhancing the Processability of MOFs for Practical Applications

Deep learning-based recommendation system for metal-organic frameworks (MOFs)

This work presents a recommendation system for metal-organic frameworks (MOFs) inspired by online content platforms. By leveraging the unsupervised Doc2Vec model trained on document-structured intrinsic MOF characteristics, the model embeds MOFs into a high-dimensional chemical space and suggests a pool of promising materials for specific applications based on user-endorsed MOFs with similarity analysis. This proposed approach significantly reduces the need for exhaustive labeling of every material in the database, focusing instead on a select fraction for in-depth investigation. Ranging from methane storage and carbon capture to quantum properties, this study illustrates the system's adaptability to various applications.

Recent Progress in MOF-Aerogel Fabrication and Applications

Recent advancements in metal-organic frameworks (MOFs) underscore their significant potential in chemical and materials research, owing to their remarkable properties and diverse structures. Despite challenges like intrinsic brittleness, powdered crystalline nature, and limited stability impeding direct applications, MOF-based aerogels have shown superior performance in various areas, particularly in water treatment and contaminant removal. This review highlights the latest progress in MOF-based aerogels, with a focus on hybrid systems incorporating materials like graphene, carbon nanotube, silica, and cellulose in MOF aerogels, which enhance their functional properties. The manifold advantages of MOF-based aerogels in energy storage, adsorption, and catalysis are discussed, with an emphasizing on their improved stability, processability, and ease of handling. This review aims to unlock the potential of MOF-based aerogels and their real-world applications. Aerogels are expected to reshape the technological landscape of MOFs through enhanced stability, adaptability, and efficiency.

Highly Efficient Photocatalytic Degradation of Imidacloprid Based on Iron Metal-Organic Frameworks of Mesoporous NH2-MIL-88b/Graphite Carbon Nitride Nanocomposites by Visible Light Driven in Aqueous Media

Pesticides that protect crops from insects and other pests are some of the main causes of water pollution. Imidacloprid (IMC) is the most widely used insecticide in the world and should be removed from the environment. This work aims to prepare mesoporous nanocomposites to increase the photodegradation efficiency of IMC. To improve the surface properties and enhance the photocatalytic activity, mesoporous nanocomposites with different weight ratios of graphite carbon nitride (CN = 125, 250, and 500 mg) were prepared by the solvothermal method. Mesoporous NH2-MIL-88b(Fe)/graphite carbon nitride (CN = 250 mg, NH2-MCN-2) nanocomposites showed the best photocatalytic performance. To save the time and cost of the experiments, central composite design (CCD) and response surface methodology (RSM) were used and the results were obtained as the initial concentration of IMC (20 mg L-1), amount of photocatalyst (0.76 g L-1), pH = 5, and degradation time ∼46 min. The maximum photocatalytic degradation efficiency estimated by the model was obtained at 96.31%, which is very close to the actual value of 95.47%. The mesoporous NH2-MCN-2 nanocomposite showed excellent stability and suitable reusability with a maximum degradation of 84.5% after five cycles. Results obtained from kinetic studies indicated a rate constant value of 0.08 min-1, and isotherm models showed that equilibrium data are more consistent with the Langmuir model in photocatalytic degradation. Electrochemical experiments showed significant improvement in the electron transfer rate and photocatalytic activity of the mesoporous NH2-MCN-2 nanocomposite. Different trapping agents were used to investigate the effective active species in IMC photodegradation, and it was determined that the hole (h+) and OH radical (•OH) play the main role. The possible mechanism for IMC photocatalytic degradation was suggested by Mott-Schottky (M-S) electrochemical impedance.

Bells and Whistles on Fertilizers: Molecular Hands to Hang Nanoporous Foliar Fertilizer Reservoirs

Porous materials are highly explored platforms for fertilizer delivery. Among porous materials, metal-organic frameworks (MOFs) are an important class of coordination polymers in which metal ions and organic electron donors as linkers are assembled to form crystalline structures with stable nanoporosity. Selected amino acids were inherently found to have the capacity to hold the leaf cuticle. Hence, MOF synthesis was attempted in the presence of amino acids, which can act as surface terminators and can assist as hands to hold to the leaf for a controlled nutrient supply. By serendipity, the amino acids were found to act as modulators, resulting in well-stabilized porous MOF structures with iron metal nodes, which are often noted to be unstable. Thus, the composite, i.e., (MOF@aa) MOF modulated with amino acids, has efficient nutrient-feeding ability through the foliar route when compared to the control.

Copper single-site engineering in MOF-808 membranes for improved water treatment

MOF-808, a metal-organic framework containing Zr6O8 clusters, can serve as a secure anchoring point for stabilizing copper single-sites with redox activity, thus making it a promising candidate for catalytic applications. In this study, we target the incorporation of Cu-MOF-808 into a mixed-matrix membrane for the degradation of tyrosol, an emerging endocrine-disrupting compound commonly found in water sources, through Fenton reactions, developing innovative technologies for water treatment. We successfully demonstrate the effectiveness of this approach by preparing catalytic membranes with minimal metal leaching, which is one of the primary challenges in developing copper-based Fenton heterogeneous catalysts. Furthermore, we utilized advanced synchrotron characterization techniques, combining X-ray absorption spectroscopy and pair distribution function analysis of X-ray total scattering, to provide evidence of the atomic structure of the catalytic copper sites within the membranes. Additionally, we observed the presence of weak interactions between the MOF-808 and the organic polymer, potentially explaining their enhanced stability.

Metal-Organic Framework-Based Composites for the Adsorption Removal of Per- and Polyfluoroalkyl Substances from Water

The increasing health risks posed by per- and polyfluoroalkyl substances (PFASs) in the environment highlight the importance of implementing effective removal techniques. Conventional wastewater treatment processes are inadequate for removing persistent organic pollutants. Recent studies have increasingly demonstrated that metal-organic frameworks (MOFs) are capable of removing PFASs from water through adsorption techniques. However, there is still constructive discussion on the potential of MOFs in adsorbing and removing PFASs for large-scale engineering applications. This review systematically investigates the use of MOFs as adsorbents for the removal of PFAS in water treatment. This primarily involved a comprehensive analysis of existing literature to understand the adsorption mechanisms of MOFs and to identify factors that enhance their efficiency in removing PFASs. We also explore the critical aspects of regeneration and stability of MOFs, assessing their reusability and long-term performance, which are essential for large-scale water treatment applications. Finally, our study highlights the challenges of removing PFASs using MOFs. Especially, the efficient removal of short-chain PFASs with hydrophilicity is a major challenge, while medium- to long-chain PFASs are frequently susceptible to being captured from water by MOFs through multiple synergistic effects. The ion-exchange force may be the key to solving this difficulty, but its susceptibility to ion interference in water needs to be addressed in practical applications. We hope that this review can provide valuable insights into the effective removal and adsorption mechanisms of PFASs as well as advance the sustainable utilization of MOFs in the field of water treatment, thereby presenting a novel perspective.

Stability of Zr-Based UiO-66 Metal-Organic Frameworks in Basic Solutions

Although Zr-based metal-organic frameworks (MOFs) exhibit robust chemical and physical stability in the presence of moisture and acidic conditions, their susceptibility to nucleophilic attacks from bases poses a critical challenge to their overall stability. Herein, we systematically investigate the stability of Zr-based UiO-66 (UiO = University of Oslo) MOFs in basic solutions. The impact of 11 standard bases, including inorganic salts and organic bases, on the stability of these MOFs is examined. The destruction of the framework is confirmed through powder X-ray diffraction (PXRD) patterns, and the monitored dissolution of ligands from the framework is assessed using nuclear magnetic resonance (NMR) spectroscopy. Our key findings reveal a direct correlation between the strength and concentration of the base and the destruction of the MOFs. The summarized data provide valuable insights that can guide the practical application of Zr-based UiO-66 MOFs under basic conditions, offering essential information for their optimal utilization in various settings.

In situ facile synthesis and antibacterial activity of Ag-MOFs/cellulose filter paper composites for fruit fresh-keeping

A large number of fresh fruits are wasted in the supply chain due to spoilage, so it is crucial to develop fruit preservation materials. Herein, two novel Ag-MOFs/carboxymethyl filter paper (Ag-MOFs/CMFP) composites were successfully synthesized by in situ facile synthesis, which can be used as packaging materials to delay fruit spoilage. The synthesis process is simple and environmentally friendly, and the reaction conditions are mild. The mechanical property, water stability, and antibacterial activity of the as-synthesized Ag-MOFs/CMFP composites were investigated. Specifically, the composites exhibited high mechanical performance and the tensile strength was >10.00 MPa. Moreover, the composites displayed good water stability and can remain stable in water environment for >7 days, which can be attributed to the strong interaction between Ag-MOFs and CMFP. Significantly, Ag-MOF particles endow the composite papers with excellent antibacterial activity, which can inactivate 99.9 % of the bacteria. Attributed to these characteristics, these composite papers were used as fruit fresh-keeping materials and can prolong the shelf-life of cherry tomatoes and peaches for >10 days. This research not only provides a facile synthesis strategy for the flexible MOFs paper, but also provides instructive guidance for related research on fruit preservation materials.

Recent progress of MOF-functionalized nanocomposites: From structure to properties

Metal-organic frameworks (MOFs) are novel crystalline porous materials assembled from metal ions and organic ligands. The adaptability of their design and the fine-tuning of the pore structures make them stand out in porous materials. Furthermore, by integrating MOF guest functional materials with other hosts, the novel composites have synergistic benefits in numerous fields such as batteries, supercapacitors, catalysis, gas storage and separation, sensors, and drug delivery. This article starts by examining the structural relationship between the host and guest materials, providing a comprehensive overview of the research advancements in various types of MOF-functionalized composites reported to date. The review focuses specifically on four types of spatial structures, including MOFs being (1) embedded in nanopores, (2) immobilized on surface, (3) coated as shells and (4) assembled into hybrids. In addition, specific design ideas for these four MOF-based composites are presented. Some of them involve in situ synthesis method, solvothermal method, etc. The specific properties and applications of these materials are also mentioned. Finally, a brief summary of the advantages of these four types of MOF composites is given. Hopefully, this article will help researchers in the design of MOF composite structures.

Fiber Integrated Metal-Organic Frameworks as Functional Components in Smart Textiles

Owing to high modularity and synthetic tunability, metal-organic frameworks (MOFs) on textiles are poised to contribute to the development of state-of-the-art wearable systems with multifunctional performance. While these composite materials have demonstrated promising functions in sensing, filtration, detoxification, and biomedicine, their applicability in multifunctional systems is only beginning to materialize. This review highlights the multifunctionality and versatility of MOF-integrated textile systems. It summarizes the operational goals of MOF@textile composites, encompassing sensing, filtration, detoxification, drug delivery, UV protection, and photocatalysis. Building upon these recent advances, this review concludes with an outlook on emerging opportunities for the diverse applications of MOF@textile systems in the realm of smart wearables.

Structure and properties of metal-organic frameworks modulated by sulfate ions

Anions play a significant role in the construction of metal-organic frameworks (MOFs). Anions can affect coordination between metal ions and organic ligands, and the formation of crystal structures, thereby affecting the structure and properties of MOFs. Two novel 3D porous MOFs ({[Cd3(TIPE)2(SO4)1.6(H2O)2.4]·2.8OH·6.2H2O}n (MOF-1) and {[Cd3(TIPE)2(SO4)3(H2O)2]·10H2O}n (MOF-2)) were successfully synthesized, by introducing SO42- to design and adjust their structure and properties, in which the sulfate ions not only participated in coordination but also played a bridging role. Both MOF-1 and MOF-2 exhibited high stability and strong fluorescence properties, and their fluorescence properties also changed compared to those of previously reported 2D nonporous MOF-3 ({[Cd2(TIPE)2Cl3(ACN)]·CdCl3·3H2O}n) with an identical ligand. They could also be used in combination with MOF-3 to distinguish between Fe3+ and Cr2O72- ions, due to a change in their fluorescence properties. In this work, the structure was reshaped by introducing sulfate ions, and the role and function of the sulfate ions in the structure were studied, providing a feasible idea for the design and precise regulation of MOFs.

Self-supported MOF/cellulose-nanocrystals materials designed from ultrafiltration

Metal-organic-frameworks (MOFs) are promising materials for addressing critical issues such as petrochemical separation, water purification, energy storage and drug delivery. Their large-scale deployment, however, is hampered by a limited processability due to their powdery nature. Recently, the hybridization of MOFs with biopolymers has emerged as a greener, biocompatible strategy to shape MOFs composites into more processable membranes, films, and porous materials. In this work, cellulose nanocrystals (CNCs) were used in combination with ZIF-8 (a widely used synthetic zeolite) to produce hybrid composites through ultrafiltration. Results showed that small quantities of CNCs (1 to 20 CNC:ZIF-8 volume ratio) were sufficient to form a self-supported, dense deposit with high ZIF-8 loadings. Compared to classical MOF in situ growth strategies, this approach allowed the tuning of the composition of the final nanocomposite by controlling the nature and quantities of particles in the suspension. The fabrication of the deposit was strongly dependent on the physiochemical properties of the suspension, which were fully characterized with a set of complementary techniques, including in situ SAXS. This technique was employed to investigate the filtration process, which exhibited a homogeneous deposition of ZIF-8 particles mediated by CNC self-assembly. Finally, the available pore volume and integrity of the internal porosity of ZIF-8 were characterized by water porosimetry, demonstrating that the presence of CNCs did not alter the properties of the supported ZIF-8.

Nanoarchitectonics of Bimetallic MOF@Lab-Grade Flexible Filter Papers: An Approach Towards Real-Time Water Decontamination and Circular Economy

This study presents a novel approach to decontaminate ferrocyanide-contaminated wastewater. The work effectively demonstrates the use of bimetallic Mo/Zr-UiO-66 as a super-adsorbent for rapid sequestration of Prussian blue, a frequently found iron complex in cyanide-contaminated soils/groundwater. The exceptional performance of Mo/Zr-UiO-66 is attributed to the insertion of secondary metallic sites, which deliver synergistic effects, benefiting the inherent qualities of the framework. Moreover, to extend the industrial applications of metal-organic frameworks (MOFs) in real-world scenarios, an approach is delivered to structure the nanocrystalline powders into MOF-based macrostructures. The work demonstrates an interfacial process to develop continuous MOF nanostructures on ordinary laboratory-grade filter papers. The novelty of the work lies in the development of robust free-standing filtration materials to purify PB dye-contaminated water. Additionally, the work embraces a circular economy concept to address problems related to resource scarcity, excessive waste production, and maintenance of economic benefits. Consequently, the PB dye-loaded adsorbent waste is re-employed for the adsorption of heavy metals (Pb2+ and Cd2+ ). Simultaneously, the study aims to address the problems related to the real-time handling of powdered adsorbents, and the generation of ecologically harmful secondary waste, thereby, progressing toward a more sustainable system.

Highly Efficient and Reusable Denitrogenation Adsorbent Obtained by the Fluorination of PMA-MIL-101

A simple but efficient strategy to improve the ability of adsorptive denitrogenation (ADN) of MIL-101(M101) was studied by the in situ encapsulation of phosphomolybdic acid (PMA) and the subsequent purification of the as-synthesized product by the NH4F solution. After the NH4F treatment, the vast majority of PMA was removed, loss of organic ligand (BDC) was observed, and the fluorination of the hydroxyl group in the M101 structure occurred. The ADN activities of the Cr-MOF matrix composites before and after fluorination were studied in detail. The rest of PMA interacts strongly with M101 and assists the ADN activity. Coordination unsaturated metal sites (CUS) in M101 are formed after fluorination and also contribute to ADN activity. Further, fluoride anions replace most of the hydroxide groups in M101, which can promote the ADN of quinoline (QUI) and indole (IND) through an acid-base interaction and N-atom coordination with the CUS in M101. P-M101-F 5% exhibits the highest adsorptive capacity and excellent regeneration ability. Special emphasis in this work is placed on structure modulation (including PMA doping, CUS creation, and fluorination) of M101 for enhancing ADN activity, which provides a useful scaffold for future research in the rational design of MOF-based ADN catalysts.

Metal-Organic Framework/Polyvinyl Alcohol Composite Films for Multiple Applications Prepared by Different Methods

The incorporation of different functional fillers has been widely used to improve the properties of polymeric materials. The polyhydroxy structure of PVA with excellent film-forming ability can be easily combined with organic/inorganic multifunctional compounds, and such an interesting combining phenomenon can create a variety of functional materials in the field of materials science. The composite membrane material obtained by combining MOF material with high porosity, specific surface area, and adjustable structure with PVA, a non-toxic and low-cost polymer material with good solubility and biodegradability, can combine the processability of PVA with the excellent performance of porous filler MOFs, solving the problem that the poor machinability of MOFs and the difficulty of recycling limit the practical application of powdered MOFs and improving the physicochemical properties of PVA, maximizing the advantages of the material to develop a wider range of applications. Firstly, we systematically summarize the preparation of MOF/PVA composite membrane materials using solution casting, electrostatic spinning, and other different methods for such excellent properties, in addition to discussing in detail the various applications of MOF/PVA composite membranes in water treatment, sensing, air purification, separation, antibacterials, and so on. Finally, we conclude with a discussion of the difficulties that need to be overcome during the film formation process to affect the performance of the composite film and offer encouraging solutions.

The adsorption property of in-situ synthesis of MOF in alginate gel for ofloxacin in the wastewater

Although metal-organic frameworks (MOFs) are advantageous to the removal of organic pollutants, the general MOFs in powder form is disadvantageous to their practical applications. In-situ MOF synthesis in alginate gel is a good way to fabricate an MOF composite for many applications, which is different from blending MOF particles with polymers. In-situ synthesis of Zeolitic Imidazolate Framework-8 (ZIF-8) in alginate gel is in the form of beads with rough wrinkles and has many pores inside. When used as an absorbent, in-situ synthesis of ZIF-8 in alginate gel could remove 97.7 ± 0.9% of ofloxacin from ofloxacin solution and the equilibrium adsorption capacity is up to 160.6 ± 1.3 mg/g. During the adsorption, ofloxacin is first brought into the gel by the solvent exchange and gel microchannel adsorption, and it can then be absorbed by in-situ ZIF-8. Moreover, the adsorption efficiency can reach 85.5% even after four cycles of adsorption. We believe that in-situ synthesis of ZIF-8 in alginate gel will be an appropriate material for the removal of ofloxacin in the wastewater.

Metal-Organic Frameworks Facilitate Nucleic Acids for Multimode Synergistic Therapy of Breast Cancer

Compared with traditional medical methods, gene therapy and photodynamic therapy are the new fields of cancer treatment, and they more accurately and effectively obtain preferable therapeutic effects. In this study, a chemotherapy drug-free nanotherapeutic system based on ZIF-90 encapsulated with Ce6-G3139 and Ce6-DNAzyme for gene and photodynamic therapies was constructed. Once entering the cancer cell, the therapy system will decompose and release Zn²⁺, Ce6-G3139, and Ce6-DNAzyme in the acidic environment. On the one hand, G3139 binds to the antiapoptotic gene BCL-2 in tumor cells and downregulates related proteins to inhibit tumor proliferation. On the other hand, Zn²⁺ produced by the decomposition of ZIF-90 can be used as a cofactor to activate the cleavage activity of DNAzyme to initiate gene therapy. Proliferation and metastasis of tumors were further inhibited by DNAzyme, targeting and cutting the gene of human early growth factor-1 (EGR-1). In addition, the photosensitizer Ce6 carried by the nucleic acid will produce cytotoxic ROS to kill cancer cells after irradiation. The results of this study demonstrated that the designed nanoplatform, which synergistically combines gene and photodynamic therapies, has shown great potential for cancer treatment.

Fabrication of Cellulose Filters Incorporating Metal-Organic Frameworks for Efficient Nicotine Adsorption from Cigarette Smoke

To prevent negative effects of smoking, there is constant research on the development of various types of sustainable filter materials, capable of removing toxic compounds present in cigarette smoke. Because of the extraordinary porosity and adsorption properties, metal-organic frameworks (MOFs) represent promising adsorbents for volatile toxic molecules such as nicotine. This study reports new hybrid materials wherein six types of common MOFs of different porosity and particle size are incorporated into sustainable cellulose fiber from bamboo pulp, resulting in a series of cellulose filter samples abbreviated as MOF@CF. The obtained hybrid cellulose filters were fully characterized and investigated in nicotine adsorption from cigarette smoke, using a specially designed experimental setup. The results revealed that the UiO-66@CF material features the best mechanical performance, facile recyclability, and excellent nicotine adsorption efficiency that attains 90% with relative standard deviations lower than 8.80%. This phenomenon may be caused by the large pore size, open metal sites, and high loading of UiO-66 in cellulose filters. Additionally, the high adsorption capacity showed almost 85% removal of nicotine after the third adsorption cycle. The DFT calculation methods allowed further investigation of the nicotine adsorption mechanism, showing that the energy difference between HOMO and LUMO for UiO-66 was the closest to that of nicotine, which further proves the adsorption ability of nicotine by this material. Owing to the flexibility, recyclability, and excellent adsorption performance, the prepared hybrid MOF@CF materials may find prospective applications in nicotine adsorption from cigarette smoke.

First-Principles Perspective on Gas Adsorption by [Fe4S4]-Based Metal-Organic Frameworks

[Fe₄S₄] or [4S-4Fe] clusters are responsible for storing and transferring electrons in key cellular processes and interact with their microenvironment to modulate their oxidation and magnetic states. Therefore, these clusters are ideal for the metal node of chemically and electromagnetically tunable metal-organic frameworks (MOFs). To examine the adsorption-based applications of [Fe₄S₄]-based MOFs, we used density functional theory calculations and studied the adsorption of CO₂, CH₄, H₂O, H₂, N₂, NO₂, O₂, and SO₂ onto [Fe₄S₄]⁰, [Fe₄S₄]²⁺, and two 1D MOF models with the carboxylate and 1,4-benzenedithiolate organic linkers. Our reaction kinetics and thermodynamics results indicated that MOF formation promotes the oxidative and hydrolytic stability of the [Fe₄S₄] clusters but decreases their adsorption efficiency. Our study suggests the potential industrial applications of these [Fe₄S₄]-based MOFs because of their limited capacity to adsorb CO₂, CH₄, H₂O, H₂, N₂, O₂, and SO₂ and high selectivity for NO₂ adsorption.

A comprehensive review of hydrophobic silica and composite aerogels: synthesis, properties and recent progress towards environmental remediation and biomedical applications

The hydrophobicity of silica and composite aerogels has enabled them to acquire applications in a variety of fields. With remarkable structural, morphological, and physiochemical properties such as high porosity, surface area, chemical stability, and selectivity, these materials have gained much attention of researchers worldwide. Moreover, the hydrophobic conduct has enabled these aerogels to adsorb substances, i.e., organic pollutants, without collapsing the pore and network structure. Hence, considering such phenomenal properties and great adsorption potential, exploiting these materials for environmental and biomedical applications is trending. The present study explores the most recent advances in synthetic approaches and resulting properties of hydrophobic silica and composite aerogels. It presents the various precursors and co-precursors used for hydrophobization and gives a comparative analysis of drying methods. Moreover, as a major focus, the work presents the recent progress where these materials have shown promising results for various environmental remediation and biomedical applications. Finally, the bottlenecks in synthesis and applicability along with future prospects are given in conclusions.

SO2 capture and detection using a Cu(II)-metal-organic polyhedron

The SO₂ adsorption-desorption capacity at room temperature and 1 bar of the metal-organic polyhedron MOP-CDC was investigated. In addition, the qualitative solid-state absorption-emission properties of this material (before and after SO₂ exposure) were measured and tested, and it demonstrated remarkable capability for SO₂ detection. Our results represent the first example of fluorimetric SO₂ detection in a MOP.

A comprehensive review on water remediation using UiO-66 MOFs and their derivatives

Metal-organic frameworks (MOFs) are a versatile class of porous materials offering unprecedented scope for chemical and structural tunability. On account of their synthetic versatility, tunable and exceptional host-guest chemistry they are widely utilized in many prominent water remediation techniques. However, some of the MOFs present low structural stabilities specifically in aqueous and harsh chemical conditions which impedes their potential application in the field. Among the currently explored MOFs, UiO-66 exhibits structural robustness and has gained immense scientific popularity. Built with a zirconium-terephthalate framework, the strong Zr-O bond coordination contributes to its stability in aqueous, chemical, and thermal conditions. Moreover, other exceptional features such as high surface area and uniform pore size add to the grand arena of porous nanomaterials. As a result of its stable nature, UiO-66 offers relaxed admittance towards various functionalization, including synthetic and post-synthetic modifications. Consequently, the adsorptive properties of these highly stable frameworks have been modulated by the addition of various functionalities. Moreover, due to the presence of catalytically active sites, the use of UiO-66 has also been extended towards the degradation of pollutants. Furthermore, to solve the practical handling issues of the crystalline powdered forms, UiO-66 has been incorporated into various membrane supports. The incorporation of UiO-66 in various matrices has enhanced the rejection, permeate flux, and anti-fouling properties of membranes. The combination of such exceptional characteristics of UiO-66 MOF has expanded its scope in targeted purification techniques. Subsequently, this review highlights the role of UiO-66 in major water purification techniques such as adsorption, photocatalytic degradation, and membrane separation. This comprehensive review is expected to shed light on the existing developments and guide the inexhaustible futuristic scope of UiO-66 MOF.

Versatilely Manipulating the Mechanical Properties of Polymer Nanocomposites by Incorporating Porous Fillers: A Molecular Dynamics Simulation Study

Polymer nanocomposites (PNCs) have been attracting myriad scientific and technological attention due to their promising mechanical and functional properties. However, there remains a need for an efficient method that can further strengthen the mechanical performance of PNCs. Here, we propose a strategy to design and fabricate novel PNCs by incorporating porous fillers (PFs) such as metal-organic frameworks with ultrahigh specific surface areas and tunable nanospaces to polymer matrices via coarse-grained molecular dynamics simulations. Three important parameters─the polymer chain stiffness (k), the interaction strength between the PF center and the end functional groups of polymer chains (ε_center end), and the PF weight fraction (w)─are systematically examined. First, attributed to the penetration of polymer chains into PFs at a strong ε_center end, the dimension of polymer chains such as the radius of gyration and the end-to-end distance increases greatly as a function of k compared to the case of the neat polymer system. The penetration of polymer chains is validated by characterizing the radial distribution function between end functional groups and filler centers, as well as the visualization of the snapshots. Also, the dispersion state of PFs tends to be good because of the chain penetration. Then, the glass transition temperature ratio of PNCs to that of the neat systems exhibits a maximum in the case of k = 5ε, indicating that the strongest interlocking between polymer chains and PFs occurs at intermediate chain stiffness. The polymer chain dynamics of PNCs decreases to a plateau at k = 5ε and then becomes stable, and the relative mobility to that of the neat system as well presents the same variation trend. Furthermore, the mechanical property under uniaxial deformation is thoroughly studied, and intermediates k, ε_center end, and w can bring about the best mechanical property. This is because of the robust penetration and interaction, which is confirmed by calculating the stress of every component of PNCs with and without end functional groups and PF centers as well as the nonbonded interaction energy change between different components. Finally, the optimal condition (k = 5.36ε, ε_center end = 5.29ε, and w = 6.54%) to design the PNC with superior mechanical behavior is predicted by Gaussian process regression, an active machine learning (ML) method. Overall, incorporating PFs greatly enhances the entanglements and interactions between polymer chains and nanofillers and brings effective mechanical reinforcements with lower filler weight fractions. We anticipate that this will provide new routes to the design of mechanically reinforced PNCs.

Insights into High-Performance and Selective Elimination of Cationic Dye from Multicomponent Systems by Using Fe-Based Metal-Organic Frameworks

Metal-organic frameworks (MOFs), especially Fe-MOFs, have shown prospective application in eliminating organic dyes from wastewater due to their well-developed pores, water stability, easy preparation, and economy. Herein, we synthesized four types of Fe-MOFs (such as MIL-88A, MIL-88B, MIL-100, and MIL-101) using the hydrothermal method. The products were analyzed with several methods. By comparing the adsorption effect of those four types of Fe-MOFs on three kinds of dyes, it has been shown that MIL-100 owns the best adsorption efficiency on cationic organic dyes methylene blue (MB) and Rhodamine B (RhB) in 180 min, while all MOFs have slight removal capacity on methyl orange (MO). MIL-100, as an adsorbent, was studied under various research conditions, and the maximum removal efficiencies to MB, RhB, and MO were found to be up to 97.36%, 88.75%, and 13.00%, respectively. Furthermore, cationic dye MB's removal by MIL-100 was fitted with a pseudo-second-order model and Langmuir isotherm model (Q_m = 411.041 mg/g) by adsorption kinetics and isotherms research, and MIL-100 could rapidly and selectively divide MB from a binary complex aqueous solution of MB and MO. The as-fabricated MIL-100 also exhibited excellent recyclability after four adsorption-desorption recycles and can be treated as a potential substance with high removal efficiency of cationic organic dye-containing industrial effluents.

Advanced MOFs@aerogel composites: Construction and application towards environmental remediation

Environmental pollution has drawn forth advanced materials and progressive techniques concentrating on sustainable development. Metal-organic frameworks (MOFs) have aroused vast interest resulting from their excellent property in structure and function. Conversely, powdery MOFs in highly crystalline follow with fragility, poor processability and recoverability. Aerogels distinguished by the unique three-dimensional (3D) interconnected pore structures with high porosity and accessible surface area are promising carriers for MOFs. Given these, combining MOFs with aerogels at molecule level to obtain advanced composites is excepted to further enhance their performance with higher practicability. Herein, we focus on the latest studies on the MOFs@aerogel composites. The construction of MOFs@aerogel with different synthetic routes and drying methods are discussed. To explore the connection between structure and performance, pore structure engineering and quantitation of MOFs content are outlined. Furthermore, various types of MOFs@aerogel composites and their carbonized derivatives are reviewed, as well as the applications of MOFs@aerogel for environmental remediation referring to water purification and air clearing. More importantly, outlooks towards these emerging advanced composites have been presented from the perspective of practical application and future development.

Micro/macrostructure and multicomponent design of catalysts by MOF-derived strategy: Opportunities for the application of nanomaterials-based advanced oxidation processes in wastewater treatment

Advanced oxidation processes (AOPs) have demonstrated an effective wastewater treatment method. But the application of AOPs using nanomaterials as catalysts is challenged with a series of problems, including limited mass transfer, surface fouling, poor stability, and difficult recycling. Recently, metal-organic frameworks (MOFs) with high tunability and ultrahigh porosity are emerging as excellent precursors for the delicate design of the structure/composition of catalysts and many MOF-derived catalysts with distinct physicochemical characteristics have shown optimized performance in various AOPs. Herein, to elucidate the structure-composition-performance relationship, a review on the performance optimization of MOF-derived catalysts to overcome the existing problems in AOPs by micro/macrostructure and multicomponent design is given. Impressively, MOF-derived strategy for the design of catalyst materials from the aspects of microstructure, macrostructure, and multicomponent (polymetallic, heteroatom doping, M/C hybrids, etc.) is firstly presented. Moreover, important advances of MOF-derived catalysts in the application of various AOPs (Fenton, persulfate-based AOPs, photocatalysis, electrochemical processes, hybrid AOPs) are summarized. The relationship between the unique micro/macrostructure and/or multicomponent features and performance optimization in mass transfer, catalytic efficiency, stability, and recyclability is clarified. Furthermore, the challenges and future work directions for the practical application of MOF-derived catalysts in AOPs for wastewater treatment are provided.

Nanoarchitectonics of Metal-Organic Frameworks for Capacitive Deionization via Controlled Pyrolyzed Approaches

Next-generation desalination technologies are needed to meet the increasing demand for clean water. Capacitive deionization (CDI) is a thermodynamically efficient technique to treat non-potable water with relatively low salinity. The salt removal capacity and rate of CDI are highly dependent on the electrode materials, which are preferentially porous to store ions through electrosorption and/or redox reactions. Metal-organic frameworks (MOFs) with "infinite" combinations of transition metals and organic linkers simplify the production of carbonaceous materials often with redox-active components after pyrolysis. MOFs-derived materials show great tunability in both compositions and structures but require further refinement to improve CDI performance. This review article summarizes recent progress in derivatives of MOFs and MOF-like materials used as CDI electrodes, focusing on the structural and compositional material considerations as well as the processing parameters and electrode architectures of the device. Furthermore, the challenges and opportunities associated with this research area are also discussed.

Nanochannel-Based {BaZn}-Organic Framework for Catalytic Activity on Cycloaddition Reaction of Epoxides with CO2 and Deacetalization-Knoevenagel Condensation

Because of the integrated properties from chemically dissimilar metals, microporous heterometallic MOFs have wider potential applicability, which prompts us to explore the tendency collocation of different metal cations in the...

Pillararene-based molecular-scale porous materials

This review discusses the design and syntheses of molecular-scale pillar[n]arene-based porous materials with promising applications and summarises the development of using pillar[n]arenes as the building blocks of porous materials. From the perspective of "role of participation" in the syntheses of molecular-scale pillar[n]arene-based porous materials, the content can be divided into pillar[n]arenes serving as supramolecular nanovalves on surfaces and as ligands for metal-organic frameworks and covalent organic polymers. By integrating pillararenes, which possess rigid pillar-like structures, electron-rich cavities and desirable host-guest properties, with porous polymers of large surface areas and abundant active sites, applications of the resulting materials in drug release platforms, molecular recognition, sensing, detection, gas adsorption, removal of water pollution, organic photovoltaic materials and heterogeneous catalysis can be realised simultaneously and efficiently. Finally, in the conclusions and perspectives part, we put forward the challenges and viewpoints of the current research on pillar[n]arene-based porous materials. We hope this article can provide a timely and valuable reference for researchers interested in synthetic macrocycles and porous materials.

Extracellular Vesicle Nanoarchitectonics for Novel Drug Delivery Applications

Extracellular vesicles (EVs) can transfer intercellular messages in various (patho)physiological processes and transport biomolecules to recipient cells. EVs possess the capacity to evade the immune system and remain stable over long periods, identifying them as natural carriers for drugs and biologics. However, the challenges associated with EVs isolation, heterogeneity, coexistence with homologous biomolecules, and lack of site-specific delivery, have impeded their potential. In recent years, the amalgamation of EVs with rationally engineered nanostructures has been proposed for achieving effective drug loading and site-specific delivery. With the advancement of nanotechnology and nanoarchitectonics, different nanostructures with tunable size, shapes, and surface properties can be integrated with EVs for drug loading, target binding, efficient delivery, and therapeutics. Such integration may enable improved cellular targeting and the protection of encapsulated drugs for enhanced and specific delivery to target cells. This review summarizes the recent development of nanostructure amalgamated EVs for drug delivery, therapeutics, and real-time monitoring of disease progression. With a specific focus on the exosomal cargo, diverse drug delivery system, and biomimetic nanostructures based on EVs for selective drug delivery, this review also chronicles the needs and challenges of EV-based biomimetic nanostructures and provides a future outlook on the strategies posed.

Ti3C2 MXene anchors CuAu-LDH multifunctional two-dimensional nanomaterials for dual-mode detection of CEA in electrochemical immunosensors

Electrochemical immunoassays are commonly used to detect biomarkers and Ti₃C₂ MXene anchored CuAu-LDH two-dimensional hydroxide heterojunctions for dual-mode electrochemical immunosensors were fabricated in this work. Layered double hydroxides have a large surface area, high chemical stability, tunable metal composition and interchangeable anions, however, the insulating nature of LDH further limits its catalytic performance. For this reason, Ti₃C₂ Mxenes were introduced to improve this problem. 2D layers of Ti₃C₂ Mxenes with large specific surface area and excellent conductivity have been well proven and widely used. And the surface of Ti₃C₂ Mxenes (due to the presence of abundant surface functional groups), will facilitate the anchoring of metal ions and the nucleation of LDH. In addition, its excellent electrical conductivity will facilitate the electron transfer between Cu²⁺ and Cu⁺. The immunosensor not only showed a heavy square wave voltammetry (SWV) signal. It also exhibited high electrocatalytic activity for H₂O₂ redox reactions and improves the sensitivity of the Ampere Current (i-t) detection. The CEA immunosensor developed in this study showed a wide linear response (0.0001-80 ng/mL) and the lowest detection limits (SWV: 33.6 fg/mL and i-t: 45.4 fg/mL S/N = 3). The results confirmed the excellent analytical capability of the immunosensor.

Nanoarchitectonics for Hierarchical Fullerene Nanomaterials

Nanoarchitectonics is a universal concept to fabricate functional materials from nanoscale building units. Based on this concept, fabrications of functional materials with hierarchical structural motifs from simple nano units of fullerenes (C60 and C70 molecules) are described in this review article. Because fullerenes can be regarded as simple and fundamental building blocks with mono-elemental and zero-dimensional natures, these demonstrations for hierarchical functional structures impress the high capability of the nanoarchitectonics approaches. In fact, various hierarchical structures such as cubes with nanorods, hole-in-cube assemblies, face-selectively etched assemblies, and microstructures with mesoporous frameworks are fabricated by easy fabrication protocols. The fabricated fullerene assemblies have been used for various applications including volatile organic compound sensing, microparticle catching, supercapacitors, and photoluminescence systems.

A universal route to fabricate bacterial cellulose-based composite membranes for simultaneous removal of multiple pollutants

A self-standing, robust bacterial cellulose (BC)-based multifunctional composite membrane embedded with desirable nano-adsorbents has been successfully fabricated via a facile versatile strategy. As expected, the developed BC-based composite membrane enables the simultaneous and efficient removal of multiple co-existing pollutants.

Extraction of Au(III) by Microbially Reduced Metal-Organic Frameworks

Gold is a critical resource in the jewelry and electronics industries and is facing increased consumer demand. Accordingly, methods for its extraction from waste effluents and environmental water sources have been sought to supplement existing mining infrastructure. Redox-mediated treatments, such as Fe(II)-based platforms, offer promise for precipitating soluble Au(III). We hypothesized that microbial generation of Fe(II) in the presence of sorbent metal-organic frameworks could capitalize on the advantages of both biological- and chemical-driven extraction approaches. Toward this aim, we tested Au(III) removal by Shewanella oneidensis cultured with Fe(III)-based materials (ferrihydrite, Fe-BTC, MIL-100, or MIL-127). Across all tested materials, S. oneidensis generated the highest levels of redox-active Fe(II) (1.99 ± 0.27 mM) when cultured with MIL-127 as a respiratory substrate in a bicarbonate-buffered medium. This translated into superior Au(III) removal performance in terms of both removal rate and capacity (k = 2.55 ± 0.60 h^-1; Q = 183 mg g^-1). Unlike other materials tested, MIL-127 also maintained cell viability following repeated Au(III) challenges, enabling the regeneration of Fe(II) in the framework. Together, these effects facilitated the treatment of multiple cycles of Au(III) by S. oneidensis-reduced MIL-127. Overall, this work demonstrates that microbial generation of Fe(II) can facilitate the removal of Au(III), augmenting purely adsorptive platforms. Given the biological and chemical modularity of our system, our results suggest that future optimizations to microbial Fe(II) generation may offer promise for improving Au(III) extraction processes.

Series of AzTO-Based Energetic Materials: Effect of Different π-π Stacking Modes on Their Thermal Stability and Sensitivity

π-Stacking is common in materials, but different π-π stacking modes remarkably affect the properties and performances of materials. In particular, weak interactions, π-stacking and hydrogen bonding, often have a great impact on the stability and sensitivity of high-energetic compounds. Therefore, several of energetic materials based on 1,1'-dihydroxyazotetrazole (1) with a nearly flat structure, such as the salts of aminoguanidine (2), 1,3-diaminoguanidine (3), imidazole (4), pyrazole (5) and triaminoguanidine (6), and a cocrystal of 2-methylimidazole (7), were designed and synthesized. Based on single-crystal diffraction data, thermal decomposition behaviors, and the mechanical sensitivity test, the compounds of 4, 5, and 7 with face-to-face π-π stacking display outstanding thermal stability and insensitivity.

Metal-organic framework derived ultralow-loading platinum-copper catalyst: a highly active and durable bifunctional electrocatalyst for oxygen-reduction and evolution reactions

Electrocatalysts with high active oxygen reduction (ORR) and oxygen evolution reaction (OER) activities are key factors in renewable energy technologies. Unlike common strategies for adjusting the proportion of metal centers in a multi-metal organic framework (MOF), herein, we designed and synthesized bifunctional electrocatalysts using cetyltrimethylammonium bromide (CTAB)-capped ultra-low content platinum (Pt) (≤0.5 wt.% Pt) and copper (Cu) nanoparticles and doped on the surface of zinc-based MOF (Zn-MOF-74) and calcinated at 900 °C. According to the electrochemical activity, the Pt/Cu/NPC-900 exhibits superior catalytic activities towards both the ORR with the onset (E₀) and half-wave (E_1/2) potentials were 1.0 V and 0.89 V versus RHE, respectively, and OER (E_o = 1.48 V versus RHE and overpotential (η) = 0.265 V versus RHE) in an alkaline electrolyte at ambient temperature. Also, Pt/Cu/NPC-900 catalyzes through a 4^-electron process and exhibits superior stability. Such insightful findings, as well as a newly developed approach, provides rational design and synthesis of an economical and efficient strategy for bifunctional electrocatalyst development.

Peroxidase- and UV-triggered oxidase mimetic activities of the UiO-66-NH2/chitosan composite membrane for antibacterial properties

In this study, UiO-66-NH₂ metal-organic framework (MOF) nanoparticles with peroxidase and oxidase mimetic activities were incorporated into a chitosan (CS) matrix by a simple and environmentally friendly method. The UiO-66-NH₂/CS composite membrane possesses the peroxidase mimicking activity in the presence of traces of H₂O₂, thus resulting in good antibacterial properties. Intriguingly, 30 min of UV pre-irradiation of the UiO-66-NH₂/CS composite membrane, in the absence of H₂O₂, still leads to a good antibacterial activity. This was attributed to the oxidase mimetic activity and the peroxidase mimicking activity of UiO-66-NH₂. In such a way, the side effects of direct exposure to UV irradiation and H₂O₂ can be avoided for wound-healing treatments. The antibacterial mechanism was further proved by antibacterial experiments, TMB·2HCl color development experiments, reactive oxygen species generation tests and electron spin resonance tests. As a potential medical antibacterial dressing, in vitro membranes were also investigated.

Coating of Conducting and Insulating Threads with Porous MOF Particles through Langmuir-Blodgett Technique

The Langmuir-Blodgett (LB) method is a well-known deposition technique for the fabrication of ordered monolayer and multilayer thin films of nanomaterials onto different substrates that plays a critical role in the development of functional devices for various applications. This paper describes detailed studies about the best coating configuration for nanoparticles of a porous metal-organic framework (MOF) onto both insulating or conductive threads and nylon fiber. We design and fabricate customized polymethylmethacrylate sheets (PMMA) holders to deposit MOF layers onto the threads or fiber using the LB technique. Two different orientations, namely, horizontal and vertical, are used to deposit MIL-96(Al) monolayer films onto five different types of threads and nylon fiber. These studies show that LB film formation strongly depends on deposition orientation and the type of threads or fiber. Among all the samples tested, cotton thread and nylon fiber with vertical deposition show more homogenous monolayer coverage. In the case of conductive threads, the MOF particles tend to aggregate between the conductive thread’s fibers instead of forming a continuous monolayer coating. Our results show a significant contribution in terms of MOF monolayer deposition onto single fiber and threads that will contribute to the fabrication of single fiber or thread-based devices in the future.