Search Results (48)

Arsenic (As) and cadmium (Cd) in rice grains are major global food safety concerns. Iron (Fe) can help reduce both, but current Fe treatments suffer from poor stability, low leaf absorption, and fast soil immobilization, with unclear underlying mechanisms. To address these issues, an Fe-based metal–organic framework (MIL-88) was modified with sodium alginate (SA) to form MIL-88@SA. Its stability as a foliar inhibitor and its leaf absorption were tested, and its effects on As and Cd accumulation in rice were compared with those of soluble Fe (FeCl₃) and chelating Fe (HA + FeCl₃) in a field study on As–Cd co-contaminated rice paddies. Compared with the control, MIL-88@SA outperformed or matched the other Fe treatments. A single foliar spray during the tillering stage increased the rice yield by 19% and reduced the inorganic As and Cd content in the grains by 22.8% and 67.8%, respectively, while the other Fe treatments required two sprays. Its superior performance was attributed to better leaf affinity and thermal stability. Laser ablation inductively coupled plasma–mass spectrometry (LA–ICP–MS) and confocal laser scanning microscopy (CLSM) analyses revealed that Fe improved photosynthesis and alleviated As–Cd stress in leaves, MIL-88@SA promoted As and Cd redistribution, and Fe–Cd co-accumulation in leaf veins enhanced Cd retention in leaves. Full article

The phototherapeutic applications of porphyrin-based nanoscale metal–organic frameworks (nMOFs) are limited by the poor penetration of conventional excitation light sources into biological tissues. Radiodynamic therapy (RDT), which directly excites photosensitizers using X-rays, can overcome the issue of tissue penetration. However, RDT faces the problems of low energy conversion efficiency, requiring a relatively high radiation dose, and the potential to cause damage to normal tissues. Researchers have found that by using some metals with high atomic numbers (high Z) as X-ray scintillators and coordinating them with porphyrin photosensitizers to form MOF materials, the excellent antitumor effect of radiotherapy (RT) and RDT can be achieved under low-dose X-ray irradiation, which can not only effectively avoid the penetration limitations of light excitation methods but also eliminate the defect issues associated with directly using X-rays to excite photosensitizers. This review summarizes the relevant research work in recent years, in which researchers have used metal ions with high Z, such as Hf⁴⁺, Th⁴⁺, Ta⁵⁺, and Bi³⁺, in coordination with carboxyl porphyrins to form MOF materials for combined RT and RDT toward various cancer cells. This review compares the therapeutic effects and advantages of using different high-Z metals and introduces the application of the heavy atom effect. Furthermore, it explores the introduction of a chemodynamic therapy (CDT) mechanism through iron coordination at the porphyrin center, along with optimization strategies such as oxygen delivery using hemoglobin to enhance the efficacy of these MOFs as radiosensitizers. This review also summarizes the potential of these materials in preclinical applications and highlights the current challenges they face. It is expected that the summary and prospects outlined in this review can further promote preclinical biomedical research into and the development of porphyrin-based nMOFs. Full article

Iron-based metal–organic frameworks (Fe-MOFs) are promising for biomedical and environmental applications due to their porosity, tunable chemistry, and biocompatibility. This study examines how particle size, morphology, and ligand composition affect the properties and cytotoxicity of MIL-101(Fe) and MIL-88A. MIL-101(Fe) (octahedral) and MIL-88A (rod-like) were synthesized with a controlled size (~200 nm to ~5 μm). Both showed a high crystallinity and stability. Cytotoxicity assays in A549 cells revealed size- and structure-dependent effects: smaller particles of MIL-88A caused greater toxicity (32.5% viability) than MIL-101(Fe) (66.1% viability at 100 μg/mL), while larger particles were less toxic. MIL-88A also induced higher reactive oxidative species (ROS) levels and degraded more rapidly, releasing more Fe ions. Toxicity predication analysis indicated the higher inherent toxicity of MIL-88A’s ligand (fumaric acid) compared to MIL-101(Fe)’s terephthalic acid. These results demonstrate that structural and chemical factors collectively influence Fe-MOFs’ biocompatibility and highlight the importance of rational design for safer MOF applications. Full article

Understanding the reaction pathway of aldehyde deformylation catalyzed by natural enzymes has shown significance in developing synthetic methodologies and new catalysts in organic, biochemical, and medicinal chemistry. However, unlike other well-rationalized chemical processes catalyzed by cytochrome P450 (Cyt P450) superfamilies, the detailed mechanism of the P450-catalyzed aldehyde deformylation is still controversial. Challenges lie in establishing synthetic models to decipher the reaction pathways, which normally are homogeneous systems for precisely mimicking the structure of the active sites in P450s. Herein, we report a heterogeneous Cyt P450 aromatase mimic based on a porphyrinic metal–organic framework (MOF) PCN-224. Through post-metalation of iron(II) triflate with the porphyrin unit, a five-coordinated Fe^II(Porp) compound could be afforded and isolated inside the resulting PCN-224(Fe) to mimic the heme active site in P450. This MOF-based P450 mimic could efficiently catalyze the oxidative deformylation of aldehydes to the corresponding ketones under room temperature using O₂ as the sole oxidant and triethylamine as the electron source, analogous to the NADPH reductase. The catalyst could be completely recovered after the catalytic reaction without undergoing structural decomposition or compromising its reactivity, representing it as one of the most valid mimics of P450 aromatase from both the structural and functional aspects. A mechanistic study reveals a strong correlation between the catalytic activity and the C^α-H bond dissociation energy of the aldehyde substrates, which, in conjunction with various trapping experiments, confirms an unconventional mechanism initiated by hydrogen atom abstraction. Full article

Iron-based metal–organic frameworks (Fe-MOFs) are widely used for agricultural chemical delivery due to their high loading capacity, and they also have the potential to provide essential iron for plant growth. Therefore, they hold significant promise for agricultural applications. Evaluating the plant biotoxicity of Fe-MOFs is crucial for optimizing their use in agriculture. In this study, we used the natural biomacromolecule carboxymethyl cellulose (CMC) to encapsulate the Fe-MOF NH₂-MIL-101 (Fe) (MIL). Through hydroponic experiments, we investigated the biotoxic effects of Fe-MOFs on rice before and after CMC modification. The results show that the accumulation of iron in rice is dependent on the dose and the exposure concentration of Fe-MOFs. CMC modification (MIL@CMC) can reduce the release rate of Fe ions from Fe-MOFs in aqueous solutions with different pH values (5 and 7). Furthermore, MIL@CMC treatment significantly increases the absorption of iron by both the aboveground and root parts of rice. MIL@CMC significantly alleviated the growth inhibition of rice seedlings and increased the aboveground biomass of rice under medium- to high-exposure conditions. Specifically, in rice roots, MIL induced a more intense oxidative stress response, with significant increases in the activities of related antioxidant enzymes (CAT, POD, and SOD) and MDA content. Our results demonstrated that the encapsulation of NH₂-MIL-101(Fe) using CMC effectively alleviated oxidative damage and promoted the uptake and growth of iron in rice. These findings suggest that rational modification can have a positive effect on reducing the potential phytotoxicity of MOFs and improving their biosafety in agricultural applications. Full article

Arsenic contamination of water endangers the health of millions of people worldwide, affecting certain countries and regions with especial severity. Interest in the use of Fe-based metal organic frameworks (MOFs) to remove inorganic arsenic species has increased due to their stability and adsorptive properties. In this study, the performance of a synthesized Nano-{Fe-BTC} MOF, containing iron oxide octahedral chains connected by trimesic acid linkers, in adsorbing As(III) and As(V) species was investigated and compared with commercial Basolite^®F300 MOF. Despite their similarities in composition, they exhibit distinct structural characteristics in their porosity, pore size, and surface areas, which affected the adsorption processes. The kinetic data of the adsorption of As(III) and As(V) by both Fe-MOFs fitted the pseudo second-order model well, with the kinetic constant being higher for Basolite^®F300 given its higher porosity. Intraparticle diffusion was, in both cases, the rate controlling step with the contribution of film diffusion in the adsorption processes, which achieved equilibrium after 1 h. The maximum adsorption capacity for As(V), 41.66 mg g⁻¹, was obtained with Basolite^®F300 at the 6.5–10 pH range, whereas Nano-{Fe-BTC} showed a different behaviour as maximum adsorption (14.99 mg g⁻¹) was obtained at pH 2. However, both adsorbents exhibited the same performance for As(III) adsorption, which is not adsorbed at pH < 9. The Langmuir adsorption isotherm model fitted well for As(III) and As(V) adsorption by Nano-{Fe-BTC} and As(III) by Basolite^®F300, whereas the Freundlich model fitted best for As(V) given its superior structural properties. Full article

Refining synthesis strategies for metal–organic framework (MOF)-based catalysts to improve their performance and stability in an oxygen evolution reaction (OER) is a big challenge. In this study, a series of nanostructured electrocatalysts were synthesized through a solvothermal method by growing MOFs and metal–triazolates (METs) on nickel foam (NF) substrates (named MET-M/NF, M = Fe, Co, Cu), and these electrocatalysts could be used directly as OER self-supporting electrodes. Among these electrocatalysts, MET-Fe/NF exhibited the best OER performance, requiring only an overpotential of 122 mV at a current density of 10 mA cm⁻² and showing remarkable stability over 15 h. The experimental results uncovered that MET-Fe/NF underwent an in situ structural reconstruction, resulting in the formation of numerous iron/nickel (oxy)hydroxides with high OER activity. Furthermore, in a two-electrode water-splitting setup, MET-Fe/NF only required 1.463 V to achieve a current density of 10 mA cm⁻². Highlighting its potential for practical applications. This work provides insight into the design and development of efficient MOF-based OER catalysts. Full article

Efforts have been made to improve the therapeutic efficiency of tumor treatments, and metal-organic frameworks (MOFs) have shown excellent potential in tumor therapy. Monotherapy for the treatment of tumors has limited effects due to the limitation of response conditions and inevitable multidrug resistance, which seriously affect the clinical therapeutic effect. In this study, we chose to construct a multiple cascade synergistic tumor drug delivery system MIL−101(Fe)−DOX−TCPP−MnO₂@PDA−Ag (MDTM@P−Ag) using MOFs as drug carriers. Under near-infrared (NIR) laser irradiation, 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) and Ag NPs loaded on MDTM@P−Ag can be activated to generate cytotoxic reactive oxygen species (ROS) and achieve photothermal conversion, thus effectively inducing the apoptosis of tumor cells and achieving a combined photodynamic/photothermal therapy. Once released at the tumor site, manganese dioxide (MnO₂) can catalyze the decomposition of hydrogen peroxide (H₂O₂) in the acidic microenvironment of the tumor to generate oxygen (O₂) and alleviate the hypoxic environment of the tumor. Fe³⁺/Mn²⁺ will mediate a Fenton/Fenton-like reaction to generate cytotoxic hydroxyl radicals (·OH), while depleting the high concentration of glutathione (GSH) in the tumor, thus enhancing the chemodynamic therapeutic effect. The successful preparation of the tumor drug delivery system and its good synergistic chemodynamic/photodynamic/photothermal therapeutic effect in tumor treatment can be demonstrated by the experimental results of material characterization, performance testing and in vitro experiments. Full article

Aluminosilicates, abundant and crucial in both natural environments and industry, often involve uncontrollable chemical components when derived from minerals, making further chemical purification and reaction more complicated. This study utilizes pure alumina and fumed silica powders as more controllable sources, enhancing aluminosilicate reactivity through room temperature (non-firing) processing and providing a robust framework that resists mechanical stress and high temperature. By embedding iron-based metal–organic frameworks (Fe-MOF/non-firing aluminosilicate membranes) within the above matrix, these ceramic membranes not only preserve their mechanical robustness but also gain significant chemical functionality, enhancing their capacity to removing phytochromes from the vegetables. Sodium hydroxide and sodium silicate were selected as activators to successfully prepare high-strength, non-firing aluminosilicate membranes. These membranes demonstrated a flexural strength of 8.7 MPa under wet-culture conditions with a molar ratio of Al₂O₃:SiO₂:NaOH:Na₂SiO₃ at 1:1:0.49:0.16. The chlorophyll adsorption of spinach conducted on these membranes showed a removal rate exceeding 90% at room temperature and pH = 9, highlighting its potential for the selective adsorption of chlorophyll. This study underscores the potential of MOF-enhanced aluminosilicate ceramic membranes in environmental applications, particularly for agricultural pollution control. Full article

A Zn–air battery serves as an energy storage solution to address fossil energy and environmental concerns. However, sluggish kinetics in oxygen reduction reactions (ORRs) and oxygen evolution reactions (OERs) demand innovative, cost-effective, and stable bifunctional catalysts to replace precious metal catalysts. In this study, an FeCo-CNTs/KB catalyst was synthesized by pyrolyzing NH₂-MIL-101(Fe) coated with glu-Co and conductive carbon (KB). This hierarchical structure comprises carbon nanotubes (CNTs) grafted onto a carbon matrix, housing abundant FeCo nanoparticles within the nanotubes or matrix. KB introduction enhances FeCo nanoparticle dispersion and fosters uniform CNT formation with smaller diameters, thus exposing active sites. Consequently, the FeCo-CNTs/KB catalyst exhibits remarkable bifunctional electrocatalytic activity: an ORR half-wave potential of 0.84 V and an OER overpotential of 0.45 V (10 mA cm⁻²). Furthermore, the FeCo-CNTs/KB catalyst in a secondary Zn–air battery showcases enduring charge–discharge performance (≥300 h). Full article

The release of organic contaminants has grown to be a major environmental concern and a threat to the ecology of water bodies. Persulfate-based Advanced Oxidation Technology (PAOT) is effective at eliminating hazardous pollutants and has an extensive spectrum of applications. Iron-based metal–organic frameworks (Fe-MOFs) and their derivatives have exhibited great advantages in activating persulfate for wastewater treatment. In this article, we provide a comprehensive review of recent research progress on the significant potential of Fe-MOFs for removing antibiotics, organic dyes, phenols, and other contaminants from aqueous environments. Firstly, multiple approaches for preparing Fe-MOFs, including the MIL and ZIF series were introduced. Subsequently, removal performance of pollutants such as antibiotics of sulfonamides and tetracyclines (TC), organic dyes of rhodamine B (RhB) and acid orange 7 (AO7), phenols of phenol and bisphenol A (BPA) by various Fe-MOFs was compared. Finally, different degradation mechanisms, encompassing free radical degradation pathways and non-free radical degradation pathways were elucidated. This review explores the synthesis methods of Fe-MOFs and their application in removing organic pollutants from water bodies, providing insights for further refining the preparation of Fe-MOFs. Full article

A series of NH₂-functionalized nano-sized magnetic metal–organic frameworks (MOFs) were prepared in this study for Cr(VI) removal from wastewater. It was observed that not only the morphological, i.e., orientation growth of N-doped and iron-based metal–organic frameworks, but also the adsorption of magnetic MOFs is largely related to the used amount of ammonium hydroxide in preparation. For example, with increasing amounts of ammonium hydroxide used in preparation, the morphology of magnetic MOFs changed from spherical to cube and triangular cone. Moreover, the maximum adsorption capacity of spherical-magnetic MOFs, cubic-magnetic MOFs and triangular cone-magnetic MOFs could be up to 204.08 mg/g, 232.56 mg/g and 270.27 mg/g, respectively. Under optimal conditions, the adsorption process of magnetic MOFs for Cr(VI) was consistent with the pseudo-second-order rate equation (R² = 1) and Langmuir isotherm model (R² > 0.99). Therefore, magnetic MOFs developed in this work offered a viable option for the removal of Cr(VI) from wastewater. Full article

A metal–organic framework (MOF) material Mg-MOF-74 was prepared by a solvothermal method, and the influence of the solvent volume and mass–liquid ratio on the preparation process was investigated. Based on the iron-based modified biochar FeCeCu/BC obtained by the sol–gel method, functionalized modified MOF-based biochar composites were prepared by the physical mixing method, co-pyrolysis method, sol–gel method and in situ growth method. The mercury removal performance and structural characteristics of the samples were studied, and the adsorption mechanism and key action mechanism were studied by using the adsorption kinetic model. Increasing the solvent volume and the mass liquid ratio will make the crystallization and pore structure of Mg-MOF-74 worse and its mercury removal performance poor. For MOF-based FeCeCu/BC composites, the mercury removal performance of the composite samples prepared by the sol–gel method and co-pyrolysis method is the best, at 31% and 46% higher than that of modified biochar, respectively. Mg-MOF-74 plays a role in promoting pyrolysis and changing the pore structure in the composite. The mercury removal process of composite materials is the result of physical adsorption and chemical adsorption, external mass transfer and internal diffusion. Full article

The direct oxidation of methane to methanol (MTM) is a significant challenge in catalysis and holds profound economic implications for the modern chemical industry. Bioinspired metal–organic frameworks (MOFs) with active iron and copper sites have emerged as innovative catalytic platforms capable of facilitating MTM conversion under mild conditions. This review discusses the current state of the art in applying MOFs with iron and copper catalytic centers to effectuate the MTM reaction, with a focus on the diverse spectroscopic techniques employed to uncover the electronic and structural properties of MOF catalysts at a microscopic level. We explore the synthetic strategies employed to incorporate iron and copper sites into various MOF topologies and explore the efficiency and selectivity of the MOFs embedded with iron and copper in acting as catalysts, as well as the ensuing MTM reaction mechanisms based on spectroscopic characterizations supported by theory. In particular, we show how integrating complementary spectroscopic tools that probe varying regions of the electromagnetic spectrum can be exceptionally conducive to achieving a comprehensive understanding of the crucial reaction pathways and intermediates. Finally, we provide a critical perspective on future directions to advance the use of MOFs to accomplish the MTM reaction. Full article

Developing electrocatalysts with high energy conversion efficiency is urgently needed. In this work, P-Fe₃O₄/Fe@C electrodes with rich under-coordinated Fe atom interfaces are constructed for efficient pH-universal water splitting. The introduction of under-coordinated Fe atoms into the P-Fe₃O₄/Fe@C interface can increase the local charge density and polarize the 3d orbital lone electrons, which promotes water adsorption and activation to release more H^*, thus elevating electrocatalytic activity. As a donor-like catalyst, P-Fe₃O₄/Fe@C displays excellent electrocatalytic performance with overpotentials of 160 mV and 214 mV in acidic and alkaline electrolytes at 10 mA cm⁻², in addition to pH-universal long-term stability. Full article