Fe-BTC Metal-organic Frameworks Research Articles

FeBTC MOF‐Derived Fe3O4@C Nanocomposite: Controlled Synthesis and Application as Potential Adsorbent for Rhodamine Dye Elimination From Wastewater

ABSTRACTThis study explores the controlled synthesis of a novel Fe3O4@C magnetic nanocomposite derived from FeBTC metal–organic framework (MOF) and its application as an efficient adsorbent for the removal of rhodamine dye from wastewater. The FeBTC MOF was first synthesized and then thermally decomposed in a controlled oxygen atmosphere at 375°C (1 h) to form the Fe3O4@C nanocomposite with a magnetic Fe3O4 core embedded in a porous carbon matrix. A comprehensive characterization of the nanocomposite was performed using x‐ray diffraction (XRD), transmission electron microscopy (TEM), and x‐ray photoelectron spectroscopy (XPS) to confirm the successful formation and to evaluate its structural and morphological properties. The morphological investigation revealed that the particles of Fe3O4 had a spherical shape with diameter of 10–15 nm. The carbon coating appeared as a thin amorphous layer surrounding the Fe3O4 nanoparticles. The adsorption capacity of Fe3O4@C for rhodamine B (RhB) dye was assessed under various conditions, including different pH values, contact times, initial dye concentrations, and temperatures. Complete dye removal was attained in 45 min using 50 mg of the nanocomposite and 50 mL of 5.0 ppm RhB at the optimum pH of 9.1. Under the same experimental conditions, the highest adsorption capacity of 13.0 mg/g was obtained, but using 15.0 mg of the nanocomposite. Fe3O4@C nanocomposite exhibits high adsorption efficiency, with a maximum removal capacity of 100%, which is clearly superior to many conventional adsorbents. This performance can be attributed to the synergistic effects of the magnetic Fe3O4 and the large surface area of the carbon matrix. Kinetic models were employed to understand the adsorption mechanism. The adsorption kinetics followed a pseudo‐second‐order model. The reusability of the adsorbent was tested over multiple cycles and showed a minimal loss of performance (drops to 93.0% after five removal cycles). The study demonstrates that the Fe3O4@C nanocomposite is a promising candidate for the effective removal of organic dyes from wastewater, offering potential benefits for environmental remediation and sustainable water management.

Fluorescence sensor based on Methionine-Modified silver nanoparticles located on Fe-BTC metal–organic framework (Meth-AgNPs@Fe-BTC) for trace detection of fenitrothion pesticide in aqueous samples

This research introduces a new “turn-on mode” fluorescence sensor for the detection of fenitrothion (FNT) pesticide in various samples. The sensor is constructed using a porous metal–organic framework (Fe-BTC) as a template to locate silver nanoparticles (AgNPs) and methionine amino acid (Meth). Methionine acts as a bridge, facilitating the interaction between FNT and AgNPs, which subsequently results in the release of AgNPs from the composite structure. The physicochemical properties of the synthesized Meth-AgNPs@Fe-BTC composite were analyzed by Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EDAX), Transmission electron microscopy (TEM), and elemental mapping (MAP) analysis. The sensing system is based on tracking the fluorescence of the synthetic composite in such a way that the intensity of the fluorescence of the composite increases in the presence of different concentrations of fenitrothion (FNT). The effective parameters on the sensor signal, including composite dosage, pH, sonication and reaction time were investigated and optimized. The calibration graph, under optimal conditions, exhibited linearity in the concentration range of 2–95 nM for FNT, with a limit of detection of 1.9 nM. The suggested sensor was successfully validated by analyzing FNT in several real water samples and fruit juices. This research presents a significant technical achievement in the development of a fluorescence sensor for the detection of FNT, offering a sensitive and reliable method for environmental monitoring and public health preservation.

Poly(vinyl alcohol)/Chitosan Hydrogel Containing Gallic Acid-Modified Fe, Cu, and Zn Metal-Organic Frameworks (MOFs): Preparation, Characterization, and Biological Applications.

Hydrogel composites are water-swollen and three-dimensional materials that have been investigated for various biological applications, including controlled drug delivery and tissue engineering, owing to the similarity between their mechanical, electrical, and chemical properties with biological tissues. The hydrogel composites can provide a superior replication of living tissue compared to their single components. In this regard, Fe-BTC, Cu-BTC, and Zn-BTC MOFs were synthesized and modified with gallic acid (GA). The MOFs-based hydrogel composites (M-BTC-GA@PVA-CS) were finally fabricated by freezing-thawing the as-synthesized MOFs, gallic acid, chitosan, and poly(vinyl alcohol) mixture. The obtained hydrogels were characterized using techniques such as FTIR, XRD, UV-vis, SEM, EDS, and TEM. Additionally, their antibacterial activity against E. coli and S. aureus and biocompatibility were investigated. The results showed that the surface modification of M-BTC MOFs with GA improves the antibacterial performance of hydrogels and increases their biocompatibility and cell viability. Among the as-prepared M-BTC MOF-based composites, the Cu-BTC MOF-loaded hydrogels showed the highest antibacterial activity. In contrast, the lowest antibacterial effect was observed for the hydrogels with Fe-BTC MOFs. Furthermore, the H&E staining exhibited improved vascularization in Zn-BTC-GA@PVA-CS and Cu-BTC-GA@PVA-CS scaffolds compared to the Fe-BTC-GA@PVA-CS hydrogel. These MOFs-loaded hydrogels may be suitable for utilization in biological applications such as skin treatment, drug delivery, and cosmetics owing to their excellent antibacterial activity and low cytotoxicity.

The Effect of Solvent on the Characteristics of FeBTC MOF as a Potential Heterogenous Catalyst Prepared via Green Mechanochemical Process

In this study, the synthesis of FeBTC (BTC = 1,3,5-benzenetricarboxylate) also known as MIL-100 (Fe) metal organic framework (MOF) has been carried out successfully using green mechanochemical method (neat grinding and liquid assisted grinding). The effect of solvent used in the synthesis was investigated for the first time to elucidate the physicochemical properties of FeBTC including crystal structure, thermal stability, pore size and specific surface area. The physicochemical properties of all FeBTC obtained in this study were compared to commercial FeBTC (Basolite F-300), characterized using powder X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and nitrogen physisorption isotherms. All Fe-BTC MOF synthesized in this study showed improved textural properties compared to commercial Basolite F-300 such as higher crystallinity, higher surface area and larger pore size. It was found that the best synthesis method was by using the mixture of ethanol and water with equal volume ratio as solvent. The highest BET surface area of FeBTC synthesized using this method was 972 m2/g for FeBTC-EtOH/H2O. This value is 2.3 times higher than the surface area of commercial Basolite F-300 (418 m2/g). FeBTC with higher surface area is expected to have higher catalytic activity which makes this FeBTC an excellent candidate as a heterogenous catalyst for many reactions such as aldol condensation or esterification reaction. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

SERS determination of hydroxy-α-sanshool in spicy hotpot seasoning: The strategy to restrain the interference of capsaicin and its mechanism

Hydroxy-α-sanshool (α-SOH) is the principal ingredient responsible for the numbing sensation in spicy hotpot. However, utilizing surface-enhanced Raman scattering (SERS) to analyze the α-SOH in hotpot seasoning is challenging due to the significant interference of capsaicin (CAP). Therefore, two schemes were proposed to address CAP interference in hotpot seasoning, namely laccase-catalyzed conversion and metal–organic framework (MOF) interaction. Among them, Fe-BTC MOF exhibited significant anti-interference effect and the underlying mechanism is elucidated. The motion of CAP aromatic ring was constrained by steric hindrance and electrostatic interactions of Fe-BTC. Additionally, the interaction between CAP aromatic ring and conjugated triene group in α-SOH was quenched, enhancing the α-SOH SERS signal. The proposed method had a significant anti-interference effect on α-SOH quantification in the presence of CAP, significantly enhancing the α-SOH SERS signal in a range of 0.85 to 4.00 × 107. The linearity and reproducibility of the proposed hotpot seasoning testing method were also validated.

The ideal treatment for heart failer

The acid-base characteristics of the catalyst material are frequently linked to catalytic activity. Metal-organic frameworks (MOFs) have been tested as catalysts for a variety of processes. Based on the observed performance in diverse catalytic processes, Cu-BTC (with a well-defined crystalline structure) and Fe-BTC (with a gel-like porous structure) have both shown the presence of Lewis surface acid sites. In this study, researchers used Inverse Gas Chromatography (IGC) and n-butylamine thermal desorption analysis to assess the acid-base characteristics of both materials. Using acidic, basic, and amphoteric molecules, IGC experiments can access the acid-base characteristics of the material surface. The n-butylamine thermal desorption measurements, on the other hand, allow quantification of those acid and basic sites from the n-butylamine desorption curves of a sample previously saturated with that probe molecule. The Lewis acid properties obtained by both methodologies showed to be more pronounced for the Fe-BTC MOF sample. The IGC measurements exhibited values of acidity constants (KA) of 0.81 and 0.60 for Fe-BTC and Cu-BTC, respectively. Furthermore the n-butylamine thermo desorption experiments indicate total acidities of 2.06 and 0.49 mmol g−1 for Fe-BTC and Cu-BTC, respectively.

Novel Pervaporation Membranes Based on Biopolymer Sodium Alginate Modified by FeBTC for Isopropanol Dehydration

Modern society strives for the development of sustainable processes that are aimed at meeting human needs while preserving the environment. Membrane technologies satisfy all the principles of sustainability due to their advantages, such as cost-effectiveness, environmental friendliness, absence of additional reagents and ease of use compared to traditional separation methods. In the present work, novel green membranes based on sodium alginate (SA) modified by a FeBTC metal–organic framework were developed for isopropanol dehydration using a membrane process, pervaporation. Two kinds of SA-FeBTC membranes were developed: (1) untreated membranes and (2) cross-linked membranes with citric acid or phosphoric acid. The structural and physicochemical properties of the developed SA-FeBTC membranes were studied by spectroscopic techniques (FTIR and NMR), microscopic methods (SEM and AFM), thermogravimetric analysis and swelling experiments. The transport properties of developed SA-FeBTC membranes were studied in the pervaporation of water–isopropanol mixtures. Based on membrane transport properties, 15 wt % FeBTC was demonstrated to be the optimal content of the modifier in the SA matrix for the membrane performance. A membrane based on SA modified by 15 wt % FeBTC and cross-linked with citric acid possessed optimal transport properties for the pervaporation of the water–isopropanol mixture (12–100 wt % water): 174–1584 g/(m2 h) permeation flux and 99.99 wt % water content in the permeate.

Selective Adsorption of Aqueous Diclofenac Sodium, Naproxen Sodium, and Ibuprofen Using a Stable Fe3O4-FeBTC Metal-Organic Frameworka.

The FeBTC metal–organic framework (MOF) incorporated with magnetite is proposed as a novel material to solve water contamination with last generation pollutants. The material was synthesized by in situ solvothermal methods, and Fe3O4 nanoparticles were added during FeBTC MOF synthesis and used in drug adsorption. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy characterized the materials, with N2-physisorption at 77 K. Pseudo-second-order kinetic and Freundlich models were used to describe the adsorption process. The thermodynamic study revealed that the adsorption of three drugs was a feasible, spontaneous exothermic process. The incorporation of magnetite nanoparticles in the FeBTC increased the adsorption capacity of pristine FeBTC. The Fe3O4–FeBTC material showed a maximum adsorption capacity for diclofenac sodium (DCF), then by ibuprofen (IB), and to a lesser extent by naproxen sodium (NS). Additionally, hybridization of the FeBTC with magnetite nanoparticles reinforced the most vulnerable part of the MOF, increasing the stability of its thermal and aqueous media. The electrostatic interaction, H-bonding, and interactions in the open-metal sites played vital roles in the drug adsorption. The sites’ competition in the multicomponent mixture’s adsorption showed selective adsorption (DCF) and (NS). This work shows how superficial modification with a low-surface-area MOF can achieve significant adsorption results in water pollutants.

Adsorption of Malachite Green and Alizarin Red S Dyes Using Fe-BTC Metal Organic Framework as Adsorbent.

Synthetic organic dyes are widely used in various industrial sectors but are also among the most harmful water pollutants. In the last decade, significant efforts have been made to develop improved materials for the removal of dyes from water, in particular, on nanostructured adsorbent materials. Metal organic frameworks (MOFs) are an attractive class of hybrid nanostructured materials with an extremely wide range of applications including adsorption. In the present work, an iron-based Fe-BTC MOF, prepared according to a rapid, aqueous-based procedure, was used as an adsorbent for the removal of alizarin red S (ARS) and malachite green (MG) dyes from water. The synthesized material was characterized in detail, while the adsorption of the dyes was monitored by UV-Vis spectroscopy. An optimal adsorption pH of 4, likely due to the establishment of favorable interactions between dyes and Fe-BTC, was found. At this pH and at a temperature of 298 K, adsorption equilibrium was reached in less than 30 min following a pseudo-second order kinetics, with k″ of 4.29 × 10−3 and 3.98 × 10−2 g∙mg−1 min−1 for ARS and MG, respectively. The adsorption isotherm followed the Langmuir model with maximal adsorption capacities of 80 mg∙g−1 (ARS) and 177 mg∙g−1 (MG), and KL of 9.30·103 L∙mg−1 (ARS) and 51.56·103 L∙mg−1 (MG).

Tuning the properties of Fe-BTC metal-organic frameworks (MOFs) by swift heavy ion (SHI) irradiation

Impact of Swift Heavy Ion (SHI) irradiation is an effective way to tailor the properties of materials to enhance their applicability toward high-end applications. In the present investigation, hydrothermally synthesized Fe-BTC metal–organic frameworks (MOFs) were irradiated with 197Au8+ ion beam, 100 MeV at fluence range of 1 × 1011 ions/cm2 and 1 × 1012 ions/cm2. Hydrothermally synthesized Fe-BTC MOFs were characterized by X-ray diffractometer, UV-Visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), Raman spectroscopy, and Atomic Force Microscopy (AFM). The significant modifications were observed as ion fluence increases, viz. decrease of crystallite size, increase of energy bandgap, reduction in average surface roughness, and the formation of new functional group (C–H) at a higher fluences 1 × 1012 ions/cm2.

Surface acid-base properties of Cu-BTC and Fe-BTC MOFs. An inverse gas chromatography and n-butylamine thermo desorption study

Catalytic activity is usually related to the acid-base properties of the catalyst material. Metal-organic frameworks (MOFs) have been evaluated as potential catalysts for several reactions. Cu-BTC (with a well-defined crystalline structure) and Fe-BTC (with a gel-like porous structure) have both shown the presence of Lewis surface acid sites based on the observed performance in different catalytic reactions. In this work, experiments of Inverse Gas Chromatography (IGC) and n-butylamine thermo desorption analysis were carried out in order to determine the acid-base properties of both materials. The IGC measurements allow to access the acid-base properties of the material surface by using acidic, basic and amphoteric molecules. Otherwise the n-butylamine thermo desorption measurements allow the quantification of those acid and basic sites from the n-butylamine desorption curves of a sample previously saturated with that probe molecule. The Lewis acid properties obtained by both methodologies showed to be more pronounced for the Fe-BTC MOF sample. The IGC measurements exhibited values of acidity constants (KA) of 0.81 and 0.60 for Fe-BTC and Cu-BTC, respectively. Furthermore the n-butylamine thermo desorption experiments indicate total acidities of 2.06 and 0.49 mmol g−1 for Fe-BTC and Cu-BTC, respectively.

Kinetics and mechanism of enhanced photocatalytic activity under visible light irradiation using Cr2O3/Fe2O3 nanostructure derived from bimetallic metal organic framework

It is reported here for the first time, synthesis of hybrid metal oxide nanocomposites, Cr2O3/Fe2O3, from bimetallic Cr-Fe metal organic frameworks using temperature-programmed oxidation method. This facile method led to the production of high surface area photocatalyst. Cr2O3 and Fe2O3 were fabricated by thermal pyrolysis of Cr-BTC and Fe-BTC metal organic frameworks respectively. The prepared samples were characterized by XRD, IR, BET, XPS, SEM, TEM, PL, EDX and DRS. Fe3O4 as the sensitizer elevated the Cr2O3 photocatalytic activity. Furthermore, investigation of optical band gap demonstrated that Cr2O3/Fe2O3 is a visible-activated photocatalyst. With enhanced photocatalytic activity using acid blue 92 as an azo dye for photocatalyst activity investigations it was observed that after 20 min most of dyes were degraded and the solution turned colorless. The activities are due to the strong oxidative ability and efficient charge separation and transfer through the Cr2O3 and Fe2O3 in the form of composite. The photoreaction kinetics and mechanism with the nanostructures were studied.

Fabrication and investigation of PEBAX/Fe-BTC, a high permeable and CO2 selective mixed matrix membrane

Mixed matrix membranes comprising commercial poly (ether-block-amid) or PEBAX® (1657) as continues phase and Fe-BTC metal organic framework as disperse phase are fabricated via phase inversion method. To investigate membrane structure various analysis including SEM, TGA, DLS and FTIR are performed. CO2 and CH4 permeability and Selectivity are measured for all membranes at 25°C and different pressures from 3 to 25bar. Moreover, mixed gas tests are implemented for 10/90 CO2/CH4 mixture. Cross section SEM images showed proper particles distribution and good interaction between polymer and particles. The replacement of various bounds in FTIR test confirmed the good compatibility of Fe-BTC with polymer matrix too. TGA results showed acceptable thermal resistance of all membranes. Membranes permeability increased with increase in particles loading percent due to high porosity of particles and also high adsorption capacity especially for CO2 molecules. The highest CO2 permeability was belong to PEBAX/Fe-BTC 40wt.% membrane which was 425.4 Barrer. Mixed matrix membranes showed selectivity enhancement too. However, PEBAX/Fe-BTC 20wt.% membrane had the best selectivity of 22.19, in membrane with higher loading percent particles agglomeration made interfacial voids which caused selectivity decrement specially in 40wt.% loading percent. All membranes showed permeability and selectivity growth till 7bar pressures however, selectivity decreased due to plasticization effect at higher pressures of 15 and 25bar. Membrane with 25wt.% loading percent showed 50% and 9% increase in CO2 permeability and selectivity at 7bar compare to base pressure of 3bar.

Semi-crystalline Fe-BTC MOF material as an efficient support for enzyme immobilization

Metal-organic frameworks (MOFs) have revolutionized the potential applications of nanoporous materials. One of the most recent and promising applications of these materials is their use as supports for enzyme immobilization. In this context, the in-situ (one-step) methodologies, which do not require the use of MOFs with pores larger than the enzyme to be immobilized, seem to be particularly encouraging. This work presents a systematic study of the semi-crystalline Fe-BTC MOF material (commercialized as Basolite F300) employed as support of the enzymes laccase and lipase through either in-situ or post-synthesis methodology. The presence of the enzyme in the resultant solid biocatalysts was proved by CHNS chemical analysis, thermogravimetric analysis, Bradford assays and by SDS-PAGE electrophoresis. The enzymatic activity of the resultant Fe-BTC-based biocatalysts was also tested. The in-situ approach is particularly relevant due to various reasons: (i) the enzyme immobilization is given in one step; (ii) it is rapid (10min); (iii) it is very efficient in terms of encapsulation capacity (≥98% for laccase and ≥87% for lipase); (iv) the enzymes are fully retained and no leaching is observed after an initial release of only around 10% of the enzyme molecules weakly immobilized; and (v) the activity of the retained enzyme can be substantially maintained (97% with respect to the free enzyme in the case of lipase). Any of these parameters systematically improves these given by the post-synthesis (two-step) approach. Moreover, Fe-BTC widely surpasses the benefits given by other MOF-based supports either by in-situ or post-synthesis approaches.

Ethylene Epoxidation with Nitrous Oxide over Fe-BTC Metal-Organic Frameworks: A DFT Study.

The epoxidation of ethylene with N2 O over the metal-organic framework Fe-BTC (BTC=1,3,5-benzentricarboxylate) is investigated by means of density functional calculations. Two reaction paths for the production of ethylene oxide or acetaldehyde are systematically considered in order to assess the efficiency of Fe-BTC for the selective formation of ethylene oxide. The reaction starts with the decomposition of N2 O to form an active surface oxygen atom on the Fe site of Fe-BTC, which subsequently reacts with an ethylene molecule to form an ethyleneoxy intermediate. This intermediate can then be selectively transformed either by 1,2-hydride shift into the undesired product acetaldehyde or into the desired product ethylene oxide by way of ring closure of the intermediate. The production of ethylene oxide requires an activation energy of 5.1 kcal mol-1 , which is only about one-third of the activation energy of acetaldehyde formation (14.3 kcal mol-1 ). The predicted reaction rate constants for the formation of ethylene oxide in the relevant temperature range are approximately 2-4 orders of magnitude higher than those for acetaldehyde. Altogether, the results suggest that Fe-BTC is a good candidate catalyst for the epoxidation of ethylene by molecular N2 O.

Cu-BTC and Fe-BTC metal-organic frameworks: Role of the materials structural features on their performance for volatile hydrocarbons separation

The separation of alkanes (nC5 to nC9), propane and propylene, and aromatic (benzene, toluene and o-xylene) hydrocarbons using the metal-organic frameworks Cu-BTC and Fe-BTC as stationary phase was evaluated from inverse gas chromatography data. Both materials were found able to separate mixtures of these volatile hydrocarbons. The nature of such behavior is discussed according to the possible guest-host interactions during the molecules adsorption and retention in the column and considering the molecules size and shape and the porous framework topology. From the recorded chromatographic profiles, the retention times for the considered hydrocarbons were calculated and then used to obtain the involved differential adsorption heats and the values for the separation coefficient. Cu-BTC is a long-range ordered crystalline material while Fe-BTC shows gel-like features. Such structural differences modulate the pore accessibility and the adsorption interactions. In this contribution, the effects of these structural differences on the molecules adsorption and separation are discussed. From the recorded adsorption data, information on the pore volume, adsorption potentials and probable pore topology for Fe-BTC was obtained.

Structure of the FeBTC Metal–Organic Framework: A Model Based on the Local Environment Study

The local environment of iron in FeBTC, a metal organic framework commercially known as Basolite F300, is investigated combining XANES and EXAFS studies of the iron K-edge. The building block of the FeBTC can be described as an iron acetate moiety. Dehydration induces a change in the coordination of the first shell while preserving the network. We propose that the local structure around Fe atoms does not undergo a rearrangement, thus, leading to the formation of an open site. The analysis conveys that the FeBTC is a disordered network of locally ordered blocks.

Adsorption of pentane isomers on metal-organic frameworks Cu-BTC and Fe-BTC

Adsorption isotherms of n-pentane, isopentane and cyclopentane on Cu-BTC and Fe-BTC metal-organic frameworks, measured in a temperature range from 273 to 333K, have been examined. For correlations, adsorption of nitrogen at 77K and argon at 87K has been studied as well. The analysis of adsorption isotherms was based on the calculation of differential distributions of the amount adsorbed with respect to the adsorption potential. It appears that the filling of Cu-BTC micropores with nitrogen occurs in two steps due to specific interaction of nitrogen molecules with open metal sites. In contrast to nitrogen, the filling of Cu-BTC micropores with argon takes place in one step. The micropores of Fe-BTC are filled with nitrogen and argon gradually in two featureless stages indicating the unordered porous structure. Adsorption isotherms of n-pentane, isopentane and cyclopentane display especially at 273 and 293K a rectangular course with a long vertical part. This shape of C5 hydrocarbon isotherms on Cu-BTC is consistent with the shape of argon isotherms since the interactions with saturated hydrocarbons are nonspecific and thus the pores of Cu-BTC are filled in one step. The isotherms of C5 hydrocarbons on Fe-BTC show one saturation step being less sharp than in the case of Cu-BTC. Calculated isosteric adsorption heats suggest that the energy of lateral interactions between adsorbed molecules dominates the gas–solid energy heterogeneity. This domination is especially pronounced for cyclopentane adsorbed on Cu-BTC. In the case of Fe-BTC, almost constant isosteric adsorption heats show that the variations of the gas–solid interaction energy are compensated by the energy of lateral interactions.