Metal Organic Framework MIL-101 Research Articles

Optimization of cadmium adsorption on metal organic frameworks MIL-53(Fe) using response surface methodology

This research aims to optimize the cadmium adsorption on metal organic frameworks MIL-53(Fe) using response surface methodology. Specifically, the effects of the adsorption parameters, such as contact time, initial cadmium ion concentration and adsorbent dosage were examined. The experimental design and optimization process consisted of a central composite design and a response surface analysis. The adsorption experimental data were analyzed to validate the the quadratic model produced by the response surface methodology. The results indicated that the interaction between contact time and initial cadmium ion concentration affects the cadmium uptake. The maximum cadmium uptake was obtained at the optimum conditions of 85 min contact time, 46 mg adsorbent dosage and 10 mg/L initial concentration of cadmium. A maximum of 74.94% adsorption efficiency was achieved under optimum conditions, with an F-value of 65.37. The model fitting was satisfactory, as the correlation coefficient of experimental (0.9882) and predicted (0.9731) was in good agreement. This study demonstrates the effectiveness of a combined application of central composite design and response surface methodology in evaluating the effects of the factors influencing cadmium adsorption adsorption on MIL-53(Fe).

Removal of Pharmaceuticals from an Aqueous Matrix by Adsorption on Metal–Organic Framework MIL-100(Cr)

Removal of Pharmaceuticals from an Aqueous Matrix by Adsorption on Metal–Organic Framework MIL-100(Cr)

Investigation of Supercapacitor Electrodes Based on MIL-101(Fe) Metal-Organic Framework: Evaluating Electrochemical Performance through Hydrothermal and Microwave-Assisted Synthesis

Supercapacitors have garnered substantial interest owing to their capacity to deliver power effectively for short-term applications. However, current supercapacitors suffer from limited stability and low-capacity storage. Metal-organic frameworks (MOFs) have emerged as a promising solution due to their high surface area and abundant active redox sites. MOF-based electrodes combined with aqueous based electrolytes have shown potential to enhance supercapacitor performance. While there is limited literature on MIL-101(Fe) MOF-based electrodes, a comparative study was conducted to investigate the supercapacitor performance of MIL-101(Fe) electrodes synthesized using hydrothermal and microwave-assisted processes. Processing parameters, such as the method used, alter the microstructure, morphology, and uniformity of supramolecular chemistry, impacting electrochemical characteristics. This study aimed to determine the active redox reactions, chemical stability, surface area, adsorption characteristics, and electrochemical characteristics of the electrodes. The electrodes from hydrothermal synthesis [MF(ht)] exhibited excellent electrochemical activity in comparison to the microwave-assisted [MF(m)] electrodes in the three-electrode configuration. At a high current density of 7 A/g, the MF(ht) electrode displayed a remarkable specific capacitance of 775.6 F/g and a good cyclic stability (82% @ 10 A/g) after 5000 galvanostatic charge–discharge cycles. At a current density of 1 A/g, the two-electrode configuration of MF(ht) yielded a high energy density of 74.7 Wh/kg at a power density of 2160 W/kg and a decent cyclic stability after 5000 cycles. The results suggest that the MF(ht) electrodes possess remarkable electrochemical properties that make them a promising candidate for advanced applications in energy storage.

Thin films using the greenly prepared metal-organic framework MIL-100(Fe) and recycled polystyrene supported onto cellulose for the microextraction of personal care products from waters and cosmetics

The metal–organic framework MIL-100(Fe), prepared with a sustainable route, was integrated in recycled polystyrene for the preparation of thin film devices using cellulose paper as support. The resulting device was used in a thin film solid-phase microextraction method (TF-SPME) in combination with high performance liquid chromatography and photodiode array detection (HPLC-PDA) for determining 7 personal care products (PCPs) in cosmetics and swimming pool waters. A thorough optimization was performed during the preparation of the devices, studying the MOF loading and the number of layers of MIL-100(Fe)/PS supported over the cellulose paper for the TF device, together with proper optimization of several analytical microextraction aspects, such as the extraction mode and the nature of the desorption solvent. Besides, an experimental design 2k with two levels and 3 factors was applied for the optimization of the remaining parameters of the method, namely extraction time, volume of the desorption solvent, and desorption time. The entire TF-SPME-HPLC-PDA method showed adequate analytical performance features, with limits of detection down to 7.5 µg·L-1 and intermembrane precision values lower than 11 % (checked intra-day) and 19 % (checked inter-day). Several cosmetics and swimming pool waters were successfully analyzed, thus demonstrating the applicability of these thin film devices in complex samples. Besides, the proposed method was assessed by applying the main green metrics currently used.

Carbon dioxide and methane capture in metal-organic framework MIL-101(Cr) at high pressure

Due to the presence of high CO2 amounts in the natural gas stream, a variety of efforts have been employed in the search for more efficient materials for the separation of gaseous mixtures such as CO2/CH4. In this article, a metal-organic framework (MIL-101) was synthesized and characterized, which showed a wide surface area (2924.8 m2 g−1 per BET) and a high volume of pores (1.32 cm³ g−1 per DFT). This structure was used to study the adsorption capacity of CO2 and CH4 within systems pressurized up to 100 bar - where a high adsorption capacity of CO2 was evidenced under 45 °C. Moreover, it was possible to distinguish between the high selectivity of this structure for CO2 molecules and its low capture of CH4 molecules. Also, the high stability of MIL-101 was noted after 6 cycles of adsorption and desorption of CO2 under 50 bar and 45 °C, thereby maintaining its adsorption capacity and crystallinity. Finally, isotherms of CO2 adsorption were successfully adjusted with the use of the Toth model.

Self-assembled BiFeO3@MIL-101 nanocomposite for antimicrobial applications under natural sunlight

In this paper, we report on the synthesis of a new hybrid photocatalytic material activated by natural sunlight irradiation. The material consists of multiferroic nanoparticles of bismuth ferrite (BFO) modified through the growth of the Fe-based MIL-101 framework. Material characterization, conducted using various techniques (X-ray diffraction, transmission electron microscopy, FTIR, and X-ray photoelectron spectroscopies), confirmed the growth of the MIL-101 metal–organic framework on the BFO surface. The obtained system possesses the intrinsic photo-degradative properties of BFO nanoparticles significantly enhanced by the presence of MIL-101. The photocatalytic activity of this material was tested in antibacterial experiments conducted under natural sunlight exposure within the nanocomposite concentration range of 100–0.20 µg/ml. The MIL-modified BFO showed a significant decrease in both Minimum Inhibiting Concentration and Minimum Bactericide Concentration values compared to bare nanoparticles. This confirms the photo-activating effect of the MIL-101 modification. In particular, they show an increased antimicrobial activity against the tested Gram-positive species and the ability to begin to inhibit the growth of the four Escherichia coli strains, although at the maximum concentration tested. These results suggest that the new nanocomposite BiFeO3@MOF has been successfully developed and has proven to be an effective antibacterial agent against a wide range of microorganisms and a potential candidate in disinfection processes.

In-situ synthesis of single-atom CoNx clusters-decorated TiO2 for highly efficient charge separation and CO2 photoreduction

Solar-driven CO2 reduction reaction (CO2RR) to produce chemical fuels is an attractive way to alleviate the greenhouse effect and energy crisis. Herein, a novel single-atom CoNx clusters-decorated TiO2 (CoNx/TiO2) is synthesized in situ by calcining a composite derived from immersing a metal organic framework (Mil-125) into cobalt tetra(4-pyridyl)porphyrin (CoPy4) solution. The resultant CoNx/TiO2 delivers an excellent CO2RR activity with CO/CH4 yields of 24.4/119.9 μmol g−1 h−1, corresponding an overall photoactivity of 1007.6 μmol g−1 h−1, 10.6 time higher than that of TiO2 alone. It is found that CoPy4 molecules can enter Mil-125′s micropores, which helps to pyrolyze CoPy4 into highly dispersed single-atom-contained CoNx clusters and to form strong interaction with the primary nanoparticles of TiO2quasi-nanocube-like aggregated particles derived from Mil-125. These factors of CoNx/TiO2 enable efficient photogenerated charge separation, strong chemical adsorption to reactants and high atom utilization, thus providing a new strategy for constructing TiO2-based photocatalysts with highly dispersed single-atom catalytic sites for CO2 photoreduction.

Co-doped metal–organic framework MIL-125(Ti) derivate for efficient adsorption of tetracycline hydrochloride from water

Metal-organic framework (MOF) based materials have aroused much research interest owing to their unique structural features in the field of environmental purification. Herein, a MOF derivate of Co-MIL-300 was prepared by sintering the cobalt-modified MIL-125(Ti) (Co-MIL) precursor at 300 °C in an air atmosphere and used as adsorbent to remove tetracycline hydrochloride (TCH, a typical emergent pollutant) from water. The Co-MIL-300 adsorbent possesses a large specific surface area, the rich surface oxygen-containing groups, the benzene-ring structure with rich π-electrons and surface cobalt ions benefiting for TCH adsorption. The TCH adsorption on Co-MIL-300 satisfies the pseudo-second-order kinetic model and Langmuir mode well, and is found to be a spontaneous endothermic and monolayer chemical adsorption process based on covalent bonding (such as π-π conjugation interactions, hydrogen bonding, π-cation interactions, coordination bonding) adsorption mechanism. Co-MIL-300 reveals a much higher adsorption capacity than Co-MIL (2.3 times of the latter) with qmax = 321.5 mg⋅g−1 at 30 °C, and it also keeps a high adsorption capacity in a wide pH range (pH = 2–11). The coexisting CO32–, PO43-, Al3+ and Fe3+ ions can greatly inhibit TCH adsorption. Most of its adsorption capacity can be recovered in five cycles after regeneration, showing great application potential for antibiotics removal.

Weather effect and cost analysis of solar adsorption desalination system using MIL-101(cr) – Graphite oxide composite material

Solar-powered adsorption desalination systems (ADSs) are a significant way to provide clean and fresh water using environmentally friendly adsorbent materials. This work presents an innovative investigation of solar-driven ADS's performance and cost analysis using a metal–organic framework MIL-101(cr) with and without a 2D graphite oxide (GO) material. The investigation is conducted over a complete year using lumped modeling by MATLAB and TRNSYS software. The production cost of desalinated water is evaluated using solar energy and waste heat sources. It is found that the effect of adding 2D-GO to MIL-101(cr) is positive on the isotherms and negative on the kinetics properties; hence the overall performance of MIL-101(cr) and MIL-101(cr) + GO was very close with an average difference of 2%. Optimum-specific daily water production and gain output ratio achieved at summer 24 m3/ton-day and 0.7, respectively, using MIL-101(cr). The cost is estimated to be 4.7 $/m3 using solar energy and 1.01 $/m3 using waste heat. The performance parameters indicate the effectiveness of MIL-101(cr) in solar/waste heat-driven ADS at a reasonable cost to remote areas.

Infiltration of the entire violacein biosynthesis pathway into a hierarchically etched MIL-101 metal–organic framework

Infiltration of the entire violacein biosynthesis pathway into a hierarchically etched MIL-101 metal–organic framework

Fabrication of highly selective PEBA mixed matrix membranes by incorporating metal-organic framework MIL-53 (Al) for the pervaporation separation of pyridine-water mixture

Pyridine is generally found in the effluents from the synthesis of paints, rubber chemicals, vitamins, and pesticides. This study focused on improving the pervaporation (PV) performance of polyether block-amide (PEBA-2533) membranes cast on polyvinylidene fluoride (PVDF) substrate, by incorporating the MIL-53 (Al) particles to prepare mixed matrix membranes (MMMs) for pyridine separation from the aqueous solution. MIL-53 (Al) has a larger aperture size (8.5 Å) than the molecular size of the pyridine (6.0 Å), which could allow pyridine molecules to efficiently pass through its channels. The coadjacent MIL-53 particles created relatively continuous permeation pathways for the penetrants in the MMMs, which substantially enhanced the separation performance. Impressively, the resultant MMMs displayed superior pyridine separation performance at complex conditions. At 65 °C and 0.5 wt% pyridine aqueous solution, the separation factor and pyridine flux of PEBA/PVDF membrane were 17.3 and 143.5 g m−2 h−1, which were improved using MIL-53@PEBA/PVDF MMMs to 48.1 and 226.9 g m−2 h−1, respectively. Owing to the enhanced pyridine affinity, hydrophobic property, and thermal robustness, the resultant MMMs overcame the inherent trade-off between selectivity and permeability, and also displayed the promising long-term stability. These findings may provide valuable insights for developing novel MMMs with superior separation performance.

Separation of the Chlorofluorocarbon (CFC) CCl2F2 from N2 in NaY Zeolite, in MIL-127(Fe) and in the two Carbon Nanotubes CNT (9,9) and CNT (11,11)

Four well-suited porous materials for the selective adsorption of the most prominent CFC, which is CCl2F2, from the air are carbon nanotubes CNT (9,9) and CNT (11,11), NaY zeolite, and the Metal Organic Framework MIL-125(Fe). The adsorption has been investigated through molecular simulations. Simulation results and theoretical considerations show that reasons for the extraordinarily high selectivity in all four cases were found to be the differences in the enthalpy of adsorption for the various adsorbed gases rather than steric reasons. The four adsorbate–adsorbent systems have been examined at different temperatures, pressures, and concentration ratios in the mixture. Among them, the carbon nanotube CNT (11,11) exhibited the highest selectivity, reaching up to 104.

Green synthesis of thiourea derivatives from nitrobenzenes using Ni nanoparticles immobilized on triazine-aminopyridine-modified MIL-101(Cr) MOF

Nanohybrid metal–organic frameworks (MOF) have recently been considered next-generation catalysts regarding their unique features like large surface-to-volume ratio, tailorable geometry, uniform pore sizes, and homogeneous distribution of active sites. In this report, we address the triazine-aminopyridine-modified 3D Cr-centred MOF MIL-101(Cr)-NH2 following a post-synthetic modification approach. The excellent chelating ability of triazine-aminopyridine was applied to immobilize Ni ions over the host matrix MOF. The as-synthesized material was physicochemically characterized using various analytical techniques like FT-IR, electron microscopy, EDS, elemental mapping, XRD, and ICP-OES. Subsequently, the material has been catalytically employed in synthesizing new thiourea derivatives by reacting to nitrobenzene derivatives and phenyl isocyanate. The catalyst was isolated by centrifugation and recycled in 6 consecutive runs without momentous loss of its reactivity.

A sustainable avenue for the synthesis of propargylamines and benzofurans using a Cu-functionalized MIL-101(Cr) as a reusable heterogeneous catalyst

A heterogeneous copper-catalyzed A3 coupling reaction of aldehydes, amines, and alkynes for the synthesis of propargylamines and benzofurans has been developed. Here, the modified metal–organic framework MIL-101(Cr)-SB-Cu complex was chosen as the heterogeneous copper catalyst and prepared via post-synthetic modification of amino-functionalized MIL-101(Cr). The structure, morphology, thermal stability, and copper content of the catalyst were determined by FT-IR, PXRD, SEM, TEM, EDX, TGA, XPS, and ICP-OES. The catalyst shows high catalytic activity for the aforementioned reactions under solvent-free reaction conditions. High yields, low catalyst loading, easy catalyst recovery and reusability with not much shrink in catalytic activity, and a good yield of 82% in gram-scale synthesis are some of the benefits of this protocol that drove it towards sustainability.

Comparative analyses of MIL-88B(Fe) and MIL-100(Fe) metal organic frameworks as active anode materials for Li ion batteries

Two Fe based metal organic framework (MOF) nanorod structures, MIL-88B(Fe) and MIL-100(Fe), were synthesized and their performance as working electrodes for Li ion half-cell batteries was evaluated under identical testing conditions. It was found that MIL-88B(Fe) provides a charge / discharge capacity of 468 mAh/g at the current density of 100 mA/g, which is over 3 times higher as compared to that of MIL-100(Fe) under the same conditions. Nevertheless, after an impressive charge / discharge capacity in the first few cycles, a slow capacity degradation was noticed in the case of the MIL-88B(Fe) material. Energy dispersive spectroscopy (EDS) and Fourier transform infrared (FTIR) spectroscopy results suggest that capacity degradation may be due to strained metal coordination in the MIL-88B(Fe) network. In contrast, despite moderate charge / discharge capacity such issues are identified to be minimal in the case of MIL-100(Fe). Electrochemical impedance spectroscopy (EIS) analyses suggest that ohmic and polarization resistance are smaller for MIL-88B(Fe) as compared to MIL-100(Fe) (both cycle 1 and 100). This makes MIL-88B(Fe) an attractive anode over MIL-100(Fe) for Li ion batteries, but stability issues remain a concern with MIL-88(B)Fe.

Origin of the solid-state luminescence of MIL-53(Al) and its connection to the local crystalline structure

Metal-organic frameworks (MOFs) are extensively studied due to their unique surface properties, enabling many intriguing applications. Breathing MOFs, a subclass of MOFs, have gained recent interest for their ability to undergo structural changes based on factors like temperature, pressure, adsorbed molecules. Certain MOFs also exhibit remarkable optical properties useful for applications such as sensors, light-emitting diodes, and scintillators. The most promising MOFs possess high porosity, breathing properties, and photoluminescence activities, allowing for improved device responsiveness and selectivity. Understanding the relationship between crystal structures and photoluminescence properties is crucial in these cases. As studies on this topic are still very limited, we report for the first time an exhaustive study on the solid-state luminescence of the breathing MOF MIL-53(Al), that can stabilize in three different crystalline structures: open-pore, hydrated narrow-pore and closed-pore. We unveil a fascinating solid-state luminescence spectrum, comprising three partially overlapping bands, and elucidate the intricate electronic transitions within each band as well as their intimate correlation with the local crystalline structures. Our characterizations of spectroscopic properties and decay times provide a deeper understanding of the luminescent behaviour of MIL-53(Al) and demonstrate that is possible to identify present crystalline structures by optical measurements or to modify the optical properties inducing structural transitions for this type of materials. These insights could help to design next-generation, selective sensors or smart light emitting devices.

MIL-101(Fe)/BiOBr S-scheme photocatalyst for promoting photocatalytic abatement of Cr(VI) and enrofloxacin antibiotic: Performance and mechanism

The development of highly active, economical, and robust bifunctional photocatalysts is a priority for sustainable photocatalytic water remediation. Inadequately available reactive sites and sluggish interface photocarrier transfer and separation remain significant challenges in the photoreaction progress. In this study, the Fe-containing metal-organic framework (MOF) MIL-101(Fe) was integrated with BiOBr microspheres to form a competent S-scheme heterostructure for the photocatalytic mitigation of Cr(VI) and enrofloxacin (ENR) antibiotics. The optimal MIL-101(Fe)/BiOBr exhibited the highest photoactivity, with 99.4% of Cr(VI) and 84.4% of ENR eliminated upon visible-light illumination in a single-pollutant system. The photoactivity of MIL-101(Fe)/BiOBr in the decontamination of the Cr(VI)-ENR co-existence system exhibited a substantial enhancement when compared to that in a single system, owing to the improved utilization of electrons and holes resulting from the synergism between Cr(VI), ENR, and the photocatalyst. The enhanced photoactivity is attributed to two aspects: (1) the incorporation of MIL-101(Fe) results in an increased number of available reactive sites and improved solar harvesting properties; and (2) the S-scheme mechanism enables the effective spatial disassociation of photoexcited carriers and optimization of the photo-redox capability of the system. Through scavenging experiments, electron spin resonance characterization, liquid chromatography-tandem mass spectrometry analysis, and T.E.S.T. theoretical estimation, the catalytic mechanism, antibiotic degradation process, and biotoxicities of the degraded products were analyzed and confirmed. This study provides a viable strategy for building competent MOF-inorganic semiconductor S-scheme photocatalysts with superior photocatalytic decontamination performance.

Efficient purification of metal-organic framework and its trigger strategy in battery thermal management system

Metal-organic framework (MOF) MIL-101(Cr) is a sorbent that can adsorb large amounts of water, but its performance is compromised by low thermal conductivity and unstable desorption temperature. In addition, the high cost restricts its application in thermal management. We propose a novel purification method, which reduces the cost of MIL-101(Cr) by 91%. Then, based on MIL-101(Cr) and micro heat pipe array (MHPA), we design an innovative thermal management structure with great performance, MHPA@MIL-101(Cr). To cope with extreme conditions, a trigger strategy based on active dehumidification and air-cooling technologies is used to improve the temperature and temperature uniformity of cells, and the effect of their trigger time on the desorption temperature of MIL-101(Cr) is studied. In a normal condition (25 °C), the zero-energy-consumption structure controls the maximum temperature (Tmax) of the battery module below 35.99 °C at 2C rate (112A). What is more, the trigger strategy improves the temperature characteristics in an extreme condition (35 °C). As a result, the Tmax is controlled at 38.8 °C when the battery module is 2C (112A) discharged, a temperature rise of only 3.8 °C.

Determination of Aflatoxins in Peanut Oil by One-Step Solid-Phase Extraction with Metal-Organic Framework MIL-101 (Cr) Filled Syringe Filter and HPLC-MS/MS

A simple, rapid and sensitive method for the determination of aflatoxins in peanut oil was developed using MIL-101(Cr) material filled syringe filter for one-step solid-phase extraction (SPE) with high-performance liquid chromatography—tandem mass spectrometry (HPLC-MS/MS) detection. The MIL-101(Cr) sorbent was characterized and its mass, the loading solution, and the eluent were optimized; under these conditions, a matrix matching internal standard method was developed. The linear range was from 0.1 to 20 ng/mL with correlation coefficient (r) exceeding 0.9998. The recoveries were between 94.7% and 105.9% with relative standard deviations from 2.02% 6.88%. The recoveries of inter-day and intra-day measurements were from 93.0% to 98.5% and 97.6% to 100.7%. The precision values for inter-day and intra-day analyses were from 6.09% to 7.68% and 2.56% to 4.30%, respectively. The pretreatment efficiency of the developed method was superior to literature procedures and used to determine aflatoxins in 126 peanut oil samples from local markets. 38 samples had positive results and 1 sample exceeded the allowable limit. Hence, the developed protocol was suitable for the determination of aflatoxins in peanut oil.

A sampling platform incorporating 3D-printed paddles-stirrers coated with metal-organic framework MIL-100(Fe) for in-situ extraction of phenolic pollutants in biodigester supernatant and wastewater effluent samples

In this work, a portable paddle stirrer platform for solid-phase extraction of chlorophenols, p-nitrophenol, and bisphenol A is presented. These compounds are important environmental pollutants and toxic inhibitors of the anaerobic treatment of wastewater. The platform integrates 3D-printed paddle stirrers coated with the metal-organic framework MIL-100(Fe), which is prepared in 10 min using a green microwave-assisted synthesis. This coated stirrer serves as an adsorbent for the preconcentration of phenols. The device is assembled with an electric motor that agitates the sample in a sample container. The sampler can be used for in-situ extraction of the analytes, eliminating the need for transporting samples to the laboratory. The analytes are eluted through ultrasonic desorption before analysis by HPLC-DAD. An exhaustive study of the stirring and extraction parameters was conducted. Under optimum conditions, the detection limits ranged from 0.3 to 1.7 μg L−1, and the precision, expressed as the relative standard deviation, showed intraday and interday ranges of 1.2–5.1% and 4.5–6.8%, respectively. The accuracy was evaluated using spiked samples of wastewater effluent and biodigester supernatant, and it provided relative recoveries in the range of 91.5–108.5%.