Development Of Metal-organic Frameworks Research Articles

Enhancing water purification efficiency with zirconium-mercaptosuccinic acid metal-organic framework integrated mixed matrix membranes: Synthesis, comprehensive characterization, and performance insights

The development of metal-organic framework (MOF) based membranes has shown great potential to address the bottlenecks in industrial wastewater treatment. This study emphasized a novel approach involving a zirconium-based MOF (Zr-MA-MOF) with mercaptosuccinic acid (MA) as a ligand for fabricating mixed matrix membranes (MMMs). These MMMs were fabricated using a polyethersulfone (PES) matrix embedded with different nanofiller loadings of 0.25, 0.5, 0.75, and 1.0 wt%. Consequently, this study investigated the impact of Zr-MA-MOF loadings on the membrane morphology and functional performance, particularly focusing on pure water flux, rejection of salts, heavy metals, and dyes, antifouling properties, and long-term stability. The MMM with a loading of 0.75 wt% Zr-MA-MOF emerged as a standout performer, delivering an exceptional water flux of 71 Lm−2h−1 and rejection efficiencies of 80, 74, and 99 % for divalent magnesium sulfate (MgSO4), monovalent sodium chloride (NaCl), and dyes (including methylene blue, congo red, and rose bengal), respectively. The heavy metal rejection capabilities of the Zr-MA-MOF membrane were equally remarkable, with rejection rates of 90, 92, and 94 % for arsenic, chromium, and aluminum ions, respectively. Furthermore, a flux recovery ratio of 92 % showcased the great potential for sustainable industrial applications. These findings revealed that the integration of Zr-MA-MOF into membrane technology holds great potential for water treatment processes, catering to both human consumption and industrial applications for diverse wastewater treatment needs.

Mg-MOF-Derived hierarchical porous carbon fiber electrodes for efficient capacitive deionization

The development of metal organic framework (MOF) functionalized carbon nanofiber with high flexibility has attracted significant attention in the fields of electrochemistry and capacitive deionization. Especially, MOF materials with alkaline earth metal centers offer advantages such as cost-effectiveness, non-toxicity, and ease of preparation. In this study, we introduced a simple strategy for synthesizing hierarchical porous carbon nanofibers derived from Mg-MOF-containing electrospun fiber (HCNF/Mg) and explored their application in capacitive deionization (CDI). The resulting HCNF/Mg exhibits a flexible structure and boasted specific surface area (908.42 m2/g), thus providing an efficient electrosorption interface to facilitate the fast ionic diffusion. Under optimum conditions, the CDI desalination capacity achieves 22.10 mg/g, accompanied with an ultrafast adsorption rate of 2.2 mg/g/min. Furthermore, this material demonstrates remarkable stability, maintaining the capacity of 90 % over 40 cycles, positioning it as a promising candidate for practical CDI applications.

Construction of 3D-graphene/NH2-MIL-125 nanohybrids via amino-ionic liquid dual-mode bonding for advanced acetaldehyde photodegradation under high humidity

The development of metal organic framework (MOF)-based π-π conjugated structures capable of effectively transforming H2O from humid air to •OH radicals for VOCs photodegradation is a significant but difficult task. Herein, an amino-ionic liquid (NH2-IL) based dual-mode bridging strategy was proposed to connect 3D-graphene with NH2-MIL-125 forming IL-3DGr/NM(Ti) nanohybrids for advanced acetaldehyde photodegradation. The rational integration of these components was responsible for: (1) maintaining π-π conjugated electron transport system; (2) generating abundant coordinatively unsaturated sites and oxygen vacancies; (3) increasing surface area of the nanohybrids. With these attributes, IL-3DGr/NM(Ti) demonstrated enhanced charge separation and transportation electrochemical impedance spectroscopy (EIS): 7-times), acetaldehyde adsorption (22 %), light absorption (bandgap: 1.51 eV). The rapid H2O adsorption and photoconversion to •OH radicals by IL-3DGr/NM(Ti) enabled it to demonstrate superior CH3CHO photodegradation rate under high humidity, surpassing many state-of-the-art photocatalysts by 9 to 187 times under static air conditions and with nearly similar catalyst dosages* (photocatalyst weight and initial acetaldehyde concentration (mg ppm−1) ratio). Interestingly, the IL-3DGr/NM(Ti) photocatalytic activity was enhanced by increasing RH% up-to 80 %. Besides, the nanohybrids demonstrated tremendous stability, with only a 3.9 % decline observed after 5 consecutive-cycles. This strategy provides new prospects to improve the compatibility of graphene/MOF materials for futuristic photoelectrical applications under high humidity.

Linker Engineering in Mixed-Ligand Metal-Organic Frameworks for Simultaneously Enhanced Benzene Adsorption and Benzene/ Cyclohexane Separation

The development of metal-organic frameworks (MOFs) that simultaneously possess high adsorption capacity and selectivity for benzene (Bz)/cyclohexane (Cy) separation is a formidable challenge. In this study, we employ the mixed-ligand...

MOF-based stimuli-responsive controlled release nanopesticide: mini review.

By releasing an adequate amount of active ingredients when triggered by environmental and biological factors, the nanopesticides that respond to stimuli can enhance the efficacy of pesticides and contribute to the betterment of both the environment and food safety. The versatile nature and highly porous structure of metal-organic frameworks (MOFs) have recently garnered significant interest as drug carriers for various applications. In recent years, there has been significant progress in the development of metal-organic frameworks as nanocarriers for pesticide applications. This review focuses on the advancements, challenges, and potential future enhancements in the design of metal-organic frameworks as nanocarriers in the field of pesticides. We explore the various stimuli-responsive metal-organic frameworks carriers, particularly focusing on zeolitic imidazolate framework-8 (ZIF-8), which have been successfully activated by external stimuli such as pH-responsive or multiple stimuli-responsive mechanisms. In conclusion, this paper presents the existing issues and future prospects of metal-organic frameworks-based nanopesticides with stimuli-responsive controlled release.

Optimized Pore Nanospace through the Construction of a Cagelike Metal-Organic Framework for CO2/N2 Separation.

The development of metal-organic framework (MOF) adsorbents with a potential molecule sieving effect for CO2 capture and separation from flue gas is of critical importance for reducing the CO2 emissions to the atmosphere yet challenging. Herein, a cagelike MOF with a suitable cage window size falling between CO2 and N2 and the cavity has been constructed to evaluate its CO2/N2 separation performance. It is noteworthy that the introduction of coordinated dimethylamine (DMA) and N,N'-dimethylformamide (DMF) molecules not only significantly reduces the cage window size but also enhances the framework-CO2 interaction via C-H···O hydrogen bonds, as proven by molecular modeling, thus leading to an improved CO2 separation performance. Moreover, transient breakthrough experiments corroborate the efficient CO2/N2 separation, revealing that the introduction of DMA and DMF molecules plays a vital role in the separation of a CO2/N2 gas mixture.

Dual-functional fluorescent metal-organic framework based beads for visual detection and removal of oxytetracycline in real aqueous solution

The development of metal-organic frameworks (MOFs) based materials with specific structures and functions has important significance and application value in energy, environment, and material science. Herein, we developed a novel zinc-based MOF with 2-(4-carboxyphenyl)-1H-benzo[d]imidazole-5-carboxylic acid (CBC) as ligand, Zn-CBC, which exhibited large surface area, porous structure, and blue fluorescence. The material was demonstrated for simultaneous visual detection and removal of oxytetracycline (OTC) as a dual-functional platform. With the introducing of OTC that can be adsorbed by the surface group of Zn-CBC, the fluorescence emission intensity centered at 472 nm was significantly decreased attributed to the internal filtering effect (IFE) between OTC and Zn-CBC. In addition, due to the aggregation-induced emission (AIE) of OTC in the porous structure of Zn-CBC, a new fluorescence emission maximum at 540 nm appeared, which constructed a blue to yellow-green ratiometric fluorescence system. Combing the optical and adsorption properties of Zn-CBC, we innovatively prepared Zn-CBC MOF-alginate-Ca2+-polyacrylic acid polymer beads (MACPs) for sensing and removing of OTC in real water samples, which showed wide applicability in practical applications.

Auxiliary ligand-directed assembly of a non-interpenetrated cage-within-cage metal-organic framework for highly efficient C2H2/CO2 separation

The development of metal-organic frameworks (MOFs) with highly efficient adsorption and separation of acetylene is very important and challenging in chemical industry due to the explosive nature of acetylene. Porous MOFs can be constructed by inserting a second auxiliary ligand, which allows the use of large ligands to construct non-interpenetrated structures and increase pore utilization. Herein, SNNU-205 is successfully synthesized, which connects two sets of interpenetrated structures to form a double walled cage-within-cage structure by using the introduction of a second auxiliary ligand. The modified pore environment enables SNNU-205 to efficiently selectively adsorb C2H2 over CO2. At 298 K and 1 atm, SNNU-205 can uptake much more C2H2 (76.3 cm3 g−1) than CO2 (47.3 cm3 g−1), resulting in a high substance ratio of C2H2-to-CO2 (1.6). More importantly, the ideal adsorbed solution theory selectivity calculations and column breakthrough tests further indicate SNNU-205 to be promising adsorbents for C2H2 adsorption and purification.

Magnetic and optoelectronic modulation of Cu-MOF-74 films by quantum dots

The introduction of SnS:Co in Cu-MOF-74 films effectively modulates magnetic and optoelectronic performances of the MOF film, which can be considered as a promising magnetic semiconductor for spintronic and optoelectronic devices.

Development of metal-organic framework (MOF) decorated graphene oxide/MgAl-layered double hydroxide coating via microstructural optimization for anti-corrosion micro-arc oxidation coatings of magnesium alloy

• GO/LDHs coating (G/LDHs) as a connecting carrier was prepared on the MAO coating. • ZIF-8 particles continuously grow symbiotically on G/LDHs coating (ZG/LDHs coating). • ZG/LDHs coating improves corrosion resistance of AZ31 alloys. • It is feasible to build high-performance anticorrosive coatings with MOF materials. An efficient and simple in-situ growth strategy has been discovered for the preparation of highly reproducible and continuous symbiotic ZIF-8-based anticorrosion coating by using graphene oxide (GO)/MgAl-NO 3 layered double hydroxides (G/LDHs) buffer layer as a new type of connecting carrier based on micro-arc oxide (MAO) coating of AZ31 magnesium alloy. The components of ZIF-8 were adsorbed and bounded to the surface of the G/LDHs buffer layer-modified substrates to promote the nucleation of ZIF-8, thus growing a phase-pure, uniform, and good symbiosis ZIF-8 membrane. ZIF-8 particles with different growth times compensate for the grain boundary defects of the G/LDHs coating precursor buffer layer to different degrees. The prepared ZIF-8-based coating has excellent stability and corrosion resistance. The results demonstrate that the G/LDHs buffer layer provides a new channel for the MOF-modified MAO substrate of AZ31 magnesium alloy. It also proves that it is feasible to build high-performance anticorrosive coatings with MOF materials.

Hydrogen sulfide activatable metal-organic frameworks for Fluorescence Imaging-Guided Photodynamic Therapy of colorectal cancer.

Photodynamic therapy (PDT) is a promising alternative and palliative therapeutic strategy for colorectal cancer (CRC). A novel photosensitizer with higher selectivity for CRC and fewer side effects is vital for clinical application. Given that the overexpression of hydrogen sulfide (H2S) in CRC, it is expected to provide a selective stimulus for activatable photosensitizers that in respond to the specific microenvironment. Herein, we report a novel development of metal-organic frameworks (MOFs) composed of meso-Tetra (4-carboxyphenyl) porphine (TCPP) and ferric ion (Fe3+) through a facile one-pot process. Experiments both in vitro and in vivo reveal that the MOF is capable of depredating in response to the high content of H2S in tumor microenvironment of CRC. Accompanying with the degradation and release of TCPP, the fluorescence and photosensitivity effect is switched from “off” to “on”, enabling the MOF to serve as a H2S activatable nano-photosensitizer for real-time fluorescence imaging-guided and targeted PDT of CRC.

Utilizing Metal-Organic Frameworks to Achieve High-Efficiency CO2 Electroreduction

Electrochemical CO2 reduction reaction (CO2RR) is the key part of clean energy generation and utilization, which has great potential to help the world to reach the carbon-neutral energy cycle in the future. In line with the development of metal-organic frameworks (MOFs) with the large specific area and considerable porosity in the past two decades, some of the MOF-based electrocatalysts have shown superior ability to accelerate CO2RR. However, regarding such a significant CO2RR process, some critical disadvantages, including inferior robustness, low yield and selectivity, and idealistic working environment, are still required to be concentrated on. Herein, a comprehensive outline of the reaction mechanism of CO2 conversion and rational synthesis of the state-of-the-art pristine MOFs is given. Further, recent progress of pristine MOF-based electrocatalysts in CO2RR is systematically summarized. Lastly, the major limitations and future opportunities in MOF electrocatalysis for CO2RR are presented.

Tuning parameters for the synthesis of MIL-53(Al): Mn doped MIL-53(Al) as a high potential catalyst for methanol dehydration

Abstract Recently, many studies are dealing with developments of Metal-Organic Frameworks (MOFs), especially MIL-53(Al), which shows high thermal and mechanical stability. Among these, optimizing the synthesis condition of MIL-53(Al) to obtain appropriate characteristics has attracted much attention in academia and the industry. Here, the effect of synthesis time and ligand to metal molar ratio on the hydrothermal synthesis of MIL-53(Al) are pursued. The synthesized MIL-53(Al) samples are characterized by X-ray diffraction (XRD), the Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy dispersive X-ray analysis (EDX), thermal gravimetric analysis (TGA), and nitrogen adsorption-desorption technique (BET). The present study shows that MIL-53(Al) can be conventionally synthesized with a high yield within a shorter reaction time than the previous studies. Furthermore, the catalytic activity of the optimized MIL-53(Al) in the pure and Mn-doped form is studied in a methanol dehydration reaction. It is thus inferred that this popular MOF in the Mn/MIL-53(Al) form has a high activity and DME selectivity during methanol conversion. Our present results confirm the merits of employing the MIL-53(Al) as a catalyst in methanol to DME conversion, which can be an avenue for the practical application of acidic catalyst.

Encapsulating UiO-66-NH2@Pt with defective PCN-222 as an active armor to fabricate a sandwich-type nanocatalyst for the tandem synthesis via hydrogenation of nitroarenes

The heterogeneously tandem catalytic synthesis is a step-economic and work-up-saving strategy for producing chemicals, but it usually requires a special catalyst to achieve the sequential catalytic reactions. The development of metal organic frameworks provides an opportunity to fabricate multifunctional catalysts. In this work, a MOF-based sandwich-nanostructure catalyst UiO-66-NH2@Pt@PCN-222 is fabricated, which is made of the UiO-66-NH2 as the core, Pt nanoparticles as the interlayer, and the defective PCN-222 as the shell. The developed catalyst shows outstanding performance for the tandem catalytic synthesis, which is the hydrogenation of nitroarenes cascaded with β-dicarbonyl compounds to form β-ketoenamines. The selectivity of β-ketoenamines reached 98% upon the completed hydrogenation of p-nitrotoluene. The stable PCN-222 shell can be regarded as an active armor, which not only protects the Pt particles from leaching or agglomerating, but also has plenty of acid sites that are conducive to the second-step condensation. At the same time, the kinetic studies show that the armor layer also affects the activity of hydrogenation, so that the hydrogenation and condensation reactions can proceed simultaneously to give the best selectivity. Various substituted dicarbonyl compounds and structurally different nitroarenes completed the conversion with excellent conversion (90–99%) and selectivity (87–98%), and this nanocatalyst can be recycled for up to six cycles without the expense of activity.

Progress in development of metal organic frameworks for electrochemical sensing of volatile organic compounds

Organic compounds threaten human health and the environment, and hence their detection is perilous for human safety and environment protection. Metal-organic frameworks (MOFs) are the three-dimensional hybrid porous materials with large surface area, tunability and good stability. Different MOFs based instrumental and material-based approaches have been developed in this line to research and expand the knowledge of MOFs as sensing platforms for a variety of organic molecules. MOFs having π-extended aromatic structures can be exploited in electroanalytical approach and thus pose lower detection limits in sensitive and selective detection of organic moieties. The present review will focus onto the categorization of different volatile organic compounds (VOCs) along with the recent progress in the development of MOF-based electrochemical sensors for volatile organic compounds. This review will pave a way to design more MOF based electrochemical sensors with excellent analytical response.

Oriented Assembly of 2D Metal-Pyridylporphyrinic Framework Films for Giant Nonlinear Optical Limiting.

The development of metal-organic frameworks (MOFs) with nonlinear optical (NLO) properties is of pronounced significance for optical devices. Herein, a series of 2D MOFs ZnTPyP(M) (TPyP = 5,10,15,20-tetrakis(4-pyridyl)porphyrin, M = Cu, Ni, Mn, H2) films with [010]-orientation growth composed of ultrathin nanosheets from a pyridylporphyrinic ligand are first obtained by using a liquid-phase epitaxial (LPE) layer-by-layer (lbl) growth approach. ZnTPyP(M) films show a giant nonlinear optical limiting (OL) response and can be modulated by tuning the type of metalloporphyrinic ligands. As a result, ZnTPyP(Cu) film exhibits the highest nonlinear absorption coefficient of 5.7 × 10-6 m/W compared to other reported NLO materials. Density functional theory calculations were consistent with the experimental results, revealing that the tunable π-π* local excitation and the increased delocalization of the metalloporphyrinic group regulate the NLO performance of ZnTPyP(M) films. These findings provide new insight into the effect of 2D porphyrinic MOFs toward the NLO response and offer new film candidates for nonlinear OL application.

Template assisted synthesis of porous termite nest-like manganese cobalt phosphide as binder-free electrode for supercapacitors

The development of metal-organic frameworks (MOFs) opens up a new pathway of original or sacrificial template for synthesizing unique morphologies to serve as novel supercapacitor electrode materials. Herein, we describe a synthesis of termite nest-like nanostructured manganese cobalt phosphide on carbon fiber cloth (MCP/CC) by simple wet chemical method and followed by phosphorization. The fabricated MOF-derived binder-free MCP/CC electrode unveils a maximum areal capacitance (Ca) of 338 mF cm−2 at a current density of 2 mA cm−2 in 6 M KOH electrolyte. Additionally, a hybrid supercapacitor (HSC) was assembled using MCP/CC as a positive electrode and N, O, S enriched activated carbon coated CC (AC@CC) as a negative electrode, which delivered a maximum specific capacitance of 48 F g−1 at a wide potential window of 0–1.7 V. Moreover, HSC showed an excellent specific energy and power of 19.18 Wh kg−1 and 9996 W kg−1 with superior capacitance retention (94%) even after 10,000 cycles. Further, the device exhibited negligible self-discharge and have good stability even after 50 h of charge holding test. These results indicate that the MCP/CC nanostructure is a favorable electrode material for highly efficient energy storage applications.

Potential applicability of Zn0.05TiOxNy@MOF-5 nanocomposite for adsorption and electrochemical detection of Zn(II) in saline wastewater

Recent developments in metal-organic frameworks (MOFs) have gained great interest in the potentiometric sensing and adsorption removal of heavy metals. However, poor hydrochemical stability is the major challenge limiting MOFs (e.g., MOF-5) applicability in the real environmental field. Accordingly, the impregnation of MOF-5 with Zn0.05TiOxNy nanoparticles was proposed in this work to design a hydrochemical stable Zn0.05TiOxNy@MOF-5 nanocomposite for selective/sensitive adsorption and potentiometric sensing of Zn2+ ions in saline wastewater containing 10–140 g L-1 total dissolved solids (TDS). The results indicate that Zn0.05TiOxNy@MOF-5 outperformed MOF-5 for Zn2+ adsorption over five reuse cycles, with an initial uptake rate (ho) of 11.724 g mg-1 min-1 at 50 g L-1 TDS. Based on the kinetic, isotherm, and thermodynamic data, the adsorption of Zn2+ onto Zn0.05TiOxNy@MOF-5 is an endothermic and physisorption in nature (ΔHº = −12.02 kJ/mol), including electrostatic interaction and diffusion mechanisms as the main rate-limiting step. The modified screen-printed sensor (SPS) with Zn0.05TiOxNy@MOF-5 ionophore also exhibits good selectivity for Zn2+ sensing (detection limit (DL) of 2.1 × 10-8 mol L-1 = 0.0014mg L-1) over a wide working range of 10-1 to 10-8 mol L-1 (Nernstian slope = 29.7 ± 0.3 mV decade-1) and pH 3–9. At optimum pH 5, the practical usability of SPS-based Zn0.05TiOxNy@MOF-5 for Zn2+ detection was also recognized in real petroleum and sewage wastewaters with stable potentiometric response over six successive days. These findings concluded that Zn0.05TiOxNy@MOF-5 could be used as a promising adsorbent and ionophore for selective adsorption and potentiometric detection of Zn2+ ions at a real environmental scale.

The Balance between Conductivity and Electro-/Photo-Catalytic Performance of Guest-Incorporated Metal-Organic Frameworks

Porphyrin plays an important role in being a chromophore in photocatalysis and it was also investigated for years as a competent candidate in electrocatalysis when metals are loaded. In addition to being used as individual molecules, porphyrin can also be assembled into corners and cages. Moreover, with the development of Metal-Organic Frameworks (MOFs), a type of hybrid materials containing metal clusters and organic linkers, porphyrin has become one of the key building blocks when we consider making MOFs a good electro-/photo-catalyst. However, most MOFs possess insulating metal clusters as nodes which lead to the insulating nature of the whole framework. The insulating nature of MOFs hinders sufficient electro-/photo- catalytic performance. The key advantage of MOFs, on the other hand, is that they offer high loading of active sites, large cavities for great accessibility, and rigid frameworks can, if constructed properly, prevent active moieties from sintering. Herein, we evaluated the competition between conductivity and the electro-/photo- catalytic performance of porphyrin containing MOFs. The conductivity of these porphyrin containing MOFs was enhanced by guest incorporation. After modification, the electrical conductivity and electro-/photo- catalytic performance were measured separately. Surprisingly, these MOFs do not require a significant conductivity to generate a competitive electro-/photo-catalytic performance.

Fe-based metal organic framework derivative with enhanced Lewis acidity and hierarchical pores for excellent adsorption of oxygenated volatile organic compounds

A series of Fe-based metal organic framework derived materials were prepared by thermal treating MIL-100(Fe) in nitrogen atmosphere for adsorption removal of oxygenated volatile organic compounds (OVOCs) such as methanol, formaldehyde and acetone under dynamic conditions. The experimental results showed that the partially carbonized M-350 material obtained by calcining MIL-100(Fe) at 350 °C exhibited the best adsorption performance and high stability. The breakthrough adsorption capacity of M-350 for methanol was 61.5% higher than that of pure MIL-100 (Fe), and it was 24.7, 6.5 and 2.6 times higher than that of commercial activated carbon, ZSM-5 and SAPO-34 adsorbents, respectively. The excellent adsorption performance was attributed to the exposure of abundant coordinatively unsaturated iron metal sites acting as Lewis acid sites through high temperature calcination, which had a strong affinity for OVOCs. Meanwhile, a hierarchical porous structure and high specific surface area further promoted the adsorption. This work provides new insights into the further development of metal organic frameworks based functional materials for VOCs removal and purification.