Magnetic Metal-organic Framework Composites Research Articles

Construction of core-shell magnetic metal-organic framework composites Fe3O4@MIL-101(Fe, Co) for degradation of RhB by efficiently activating PMS.

Low catalytic efficiency and catalyst recovery are the key factors limiting the practical application of advanced oxidation processes. In this work, a core-shell magnetic nanostructure Fe3O4@MIL-101(Fe, Co) was prepared via a simple solvothermal method. The core-shell structure and magnetic recovery performance were characterized by various technologies. The results of dye degradation experiments proved that within 10 minutes, the Fe3O4@MIL-101(Fe, Co)/PMS system can degrade more than 95% of 10 mg per L Rhodamine (RhB) at an initial pH of 7, which possesses higher catalytic activity than the Fe3O4/PMS system and the MIL-101(Fe, Co)/PMS system. The effects of initial solution pH and coexisting anions in water on the degradation of RhB were further discussed. The results showed that Fe3O4@MIL-101(Fe, Co) displayed excellent degradation efficiency in a wide pH range of 3-11 and capability of resisting coexisting anions. It is worth mentioning that after five cycles, the RhB removal rate can still be maintained at over 90% after 10 minutes of reaction. Free radical quenching experiments were further studied, confirming that ˙OH and SO4-˙ were involved in the degradation of RhB, while the dominating active free radical was SO4-˙. The possible reaction mechanism of the RhB degradation process was also inferred.

Adsorption performance of magnetic metal–organic framework composites for Congo red and amino black 10B

Adsorption performance of magnetic metal–organic framework composites for Congo red and amino black 10B

Experimental and DFT study of adsorption-reduction mechanism of Au(III) and Cr(VI) by β-cyclodextrin/polydopamine coated UiO-66-NH2 magnetic composites

Herein, a magnetic metal–organic framework composite was constructed by loading CoFe2O4 nano-particles on β-CD-TEPA/PDA functionalized UiO-66-NH2 for Au(III)/Cr(VI) elimination. The effective synthesis and excellent structural performances of the target materials were proved by advanced characterization technology, and the introduction of β-CD-TEPA/PDA significantly enhanced adsorption-reduction efficiency of Au(III)/Cr(VI). Batch adsorption experiments showed that the water environmental conditions remarkably affected the removal process, while isotherm and kinetic adsorption demonstrated that the elimination process belonged to a uniform chemical adsorption. The maximum adsorption amounts of Au(III) (445.5 mg/g, pH = 2.0) were greater than that of Cr(VI) (96.2 mg/g, pH = 2.0), which was probably caused by the differences in the morphology and size of the two target ions. The synthesized adsorbents exhibited good adsorption selectivity for Au(III)/Cr(VI) in a mixed system, and it could easily be removed from the solution by a magnet. The spectroscopic evidence and DFT calculation revealed that Au(III)/Cr(VI) initially was bound with -NH2 and β-CD-TEPA via electrostatic attraction and chelate action. Subsequently, Au(III) was readily reduced to Au(0) and Cr(VI) was converted into Cr(III) without additional reducing agents. About Au(III) (19.20%) and Au(0) (80.80%) species co-existed onto the spent adsorbent, while it was 56.44% and 43.56% for Cr(VI) and Cr(III). Hence, this study opened up the possibility to expand the applications of MOFs materials for wastewater remediation.

Overview on recent advances of magnetic metal-organic framework (MMOF) composites in removal of heavy metals from aqueous system.

Developing a novel, simple, and cost-effective analytical technique with high enrichment capacity and selectivity is crucial for environmental monitoring and remediation. Metal-organic frameworks (MOFs) are porous coordination polymers that are self-assembly synthesized from organic linkers and inorganic metal ions/metal clusters. Magnetic metal-organic framework (MMOF) composites are promising candidate among the new-generation sorbent materials available for magnetic solid-phase extraction (MSPE) of environmental contaminants due to their superparamagnetism properties, high crystallinity, permanent porosity, ultrahigh specific surface area, adaptable pore shape/sizes, tunable functionality, designable framework topology, rapid and ultrahigh adsorption capacity, and reusability. In this review, we focus on recent scientific progress in the removal of heavy metal ions present in contaminated aquatic system by using MMOF composites. Different types of MMOFs, their synthetic approaches, and various properties that are harnessed for removal of heavy metal ions from contaminated water are discussed briefly. Adsorption mechanisms involved, adsorption capacity, and regeneration of the MMOF sorbents as well as recovery of heavy metal ions adsorbed that are reported in the last ten years have been discussed in this review. Moreover, particular prospects, challenges, and opportunities in future development of MMOFs towards their greener synthetic approaches for their practical industrial applications have critically been considered in this review.

Application of a magnetic solid-phase extraction method using a novel magnetic metal organic framework nanocomposite for extraction of malathion and diazinon pesticides from environmental water samples

Herein, a magnetic solid-phase extraction (MSPE) method using a synthesized magnetic metal-organic framework composite (Cu-MOF@Fe3O4@SiO2) was applied for the extraction of two well-known organophosphorus pesticides (Malathion and Diazinon) in several environmental water samples. After the extraction, the mentioned target analytes were measured by HPLC-UV. Under the optimal conditions obtained, acceptable linearity was observed within the concentration ranges of 10.0–500.0, and 5.0–500.0 μg/L for malathion and diazinon, respectively. The respective limits of quantification (LOQs) were determined to be 10.0 and 5.0 μg/L for malathion and diazinon. Besides, the MSPE method was successfully implemented to determine the two targets in tap water, surface water, well water, and treated waste water samples with the recoveries varying from 84.0 to 105.5 % (RSDs = 3.8–9.6 %). The obtained results indicated that the combined MOF-based MSPE/HPLC-UV method is of several valuable analytical features, such as high sensitivity, good precision, and the ease of operation and it is practically effective for the extraction and determination of organophosphorus pesticides in various water samples.

Preparation and Characterization of Magnetic Metal-Organic Frameworks Functionalized by Ionic Liquid as Supports for Immobilization of Pancreatic Lipase.

Enzymes are difficult to recycle, which limits their large-scale industrial applications. In this work, an ionic liquid-modified magnetic metal–organic framework composite, IL-Fe3O4@UiO-66-NH2, was prepared and used as a support for enzyme immobilization. The properties of the support were characterized with X-ray powder diffraction (XRD), Fourier-transform infrared (FTIR) spectra, transmission electron microscopy (TEM), scanning electronic microscopy (SEM), and so on. The catalytic performance of the immobilized enzyme was also investigated in the hydrolysis reaction of glyceryl triacetate. Compared with soluble porcine pancreatic lipase (PPL), immobilized lipase (PPL-IL-Fe3O4@UiO-66-NH2) had greater catalytic activity under reaction conditions. It also showed better thermal stability and anti-denaturant properties. The specific activity of PPL-IL-Fe3O4@UiO-66-NH2 was 2.3 times higher than that of soluble PPL. After 10 repeated catalytic cycles, the residual activity of PPL-IL-Fe3O4@UiO-66-NH2 reached 74.4%, which was higher than that of PPL-Fe3O4@UiO-66-NH2 (62.3%). In addition, kinetic parameter tests revealed that PPL-IL-Fe3O4@UiO-66-NH2 had a stronger affinity to the substrate and, thus, exhibited higher catalytic efficiency. The results demonstrated that Fe3O4@UiO-66-NH2 modified by ionic liquids has great potential for immobilized enzymes.

Magnetic metal–organic framework composites: structurally advanced catalytic materials for organic transformations

The review aims to present the recent developments in the synthesis and applications of magnetic MOF composite-based catalytic materials for expediting a broad array of industrially significant organic transformations.

Synthesis of Magnetic Metal-Organic Frame Material and Its Application in Food Sample Preparation.

A variety of contaminants in food is an important aspect affecting food safety. Due to the presence of its trace amounts and the complexity of food matrix, it is very difficult to effectively separate and accurately detect them. The magnetic metal-organic framework (MMOF) composites with different structures and functions provide a new choice for the purification of food matrix and enrichment of trace targets, thus providing a new direction for the development of new technologies in food safety detection with high sensitivity and efficiency. The MOF materials composed of inorganic subunits and organic ligands have the advantages of regular pore structure, large specific surface area and good stability, which have been thoroughly studied in the pretreatment of complex food samples. MMOF materials combined different MOF materials with various magnetic nanoparticles, adding magnetic characteristics to the advantages of MOF materials, which are in terms of material selectivity, biocompatibility, easy operation and repeatability. Combined with solid phase extraction (SPE) technique, MMOF materials have been widely used in the food pretreatment. This article introduced the new preparation strategies of different MMOF materials, systematically summarizes their applications as SPE adsorbents in the pretreatment of food contaminants and analyzes and prospects their future application prospects and development directions.

Facile magnetization of metal–organic framework TMU-6 for magnetic solid-phase extraction of organophosphorus pesticides in water and rice samples

In the present work, a magnetic metal-organic framework composite (Fe3O4@TGA@TMU-6) was synthesized and used as an adsorbent for magnetic solid-phase extraction (MSPE) of some organophosphorus pesticides (phosalone, chlorpyrifos and, profenofos) in rice and environmental water samples. Extraction, separation and determination of the analytes were performed by MSPE-HPLC-UV. Due to the large surface area and unique porous structure of the metal-organic frameworks (MOFs) as well as π-π and hydrophobic interactions between the analytes and the MOF ligands, the prepared sorbents showed a high affinity towards the target analytes. The affecting parameters on the extraction efficiency, including type and volume of eluent, pH, amount of MFC, extraction time, salt effect and desorption time were investigated and optimized. Under optimum conditions, calibration curves were found to be linear in the range of 7.5–75 μg L−1, 10–100 μg L−1, and 10–150 μg L−1 for phosalone, chlorpyrifos, and profenofos in water samples, respectively. The LODs (based on S/N = 3) were 0.5, 1 and 0.5 μg L−1 for phosalone, chlorpyrifos, and profenofos in water samples, respectively.

Adsorption of pharmaceuticals and personal care products by deep eutectic solvents-regulated magnetic metal-organic framework adsorbents: Performance and mechanism

The ecological and human health threats brought by emerging pollutants are increasingly serious. Development of efficient removal methods is urgent. Herein, seven deep eutectic solvents (DESs) composed by quaternary ammonium salts and lactic acid or glycolic acid were synthesized and used to regulate magnetic (Fe3O4) metal organic framework (MUiO-66-NH2) composites. The obtained nanoparticles (named as DES-MUiO-66-NH2) were used as adsorbents to adsorb pharmaceuticals and personal care products (PPCPs). Langmuir isotherm model and pseudo-second-order kinetics model were suitable to analyze the adsorption process of DES-MUiO-66-NH2 to PPCPs, indicated that the adsorption of PPCPs was chemisorption on homogeneous surface of DES-MUiO-66-NH2 adsorbents. Under the optimal conditions, the adsorption capacity of DES-MUiO-66-NH2 toward ofloxacin and mefenamic acid reached up to 97.60 and 79.22 mg/g, respectively. Mechanism exploration indicated that DES-MUiO-66-NH2 selectively adsorbed PPCPs through electrostatic interaction, chelation, π-π stacking, hydrophobic interaction and hydrogen bonding. Density functional theory proved the chelation through theoretical calculation. Selective experiments manifested that the structures of DESs directly determined the specificity of DES-MUiO-66-NH2 for different PPCPs, and the investigation of structure–activity relationship provided new ideas for designing efficient tailor-made adsorbents for PPCPs. The proposed PPCPs removal approach focused on the guiding role of DESs in selective adsorption. And this green DESs regulation idea provided more options for the synthesis of high-efficiency and functional adsorbents for emerging pollutants.

Magnetic metal-organic framework composites for dual-column solid-phase microextraction combined with ICP-MS for speciation of trace levels of arsenic.

A dual column packed with a magnetic metal-organic framework composite (MFC) and mercapto-functionalized MFC nanoparticles (MFC-SH) in microfluidic chip channels is described for array chip-based magnetic solid phase microextraction of arsenic species including arsenite [As(III)], arsenate [As(V)], monomethylarsonous acid (MMA) and dimethylarsinic acid (DMA) in SCC-7 cells. At pH6, the MFC-SH adsorbs As(III) while MFC quantitatively adsorbs As(V), DMA and MMA. The As(III) adsorbed on the MFC-SH can be desorbed with a 2% solution of thiourea in 0.5M HNO3. The arsenic species MMA, DMA and As(V) are retained on the MFC but can be desorbed by ammonia. A sequential elution strategy was employed to elute MMA, DMA, As(V) and As(III) one by one for subsequent on-line determination by ICP-MS. The limits of detection are 4.8, 6.3, 3.8 and 7.1ngL-1 for As(V), DMA, MMA and As(III), respectively. The enrichment factors are between 23 and 25, and the throughput is 7 samples per hour. The arsenic species in (spiked) SCC-7 cell samples were analyzed by the online system with adequate recoveries (89-110%). Graphical abstractSchematic representation of magnetic metal-organic framework composite (MFC) and mercapto-functionalized MFC nanoparticles (MFC-SH) packed dual-column, squamous carcinoma cells (SCC-7), online chip-based array MSPME-ICPMS system. Cell lysis units (blue), Microextraction units (black), Microvalves (green), Outlet (black), Permanent magnets (gray), Intet (red/purple/yellow).

Fabrication of iron oxide@MOF-808 as a sorbent for magnetic solid phase extraction of benzoylurea insecticides in tea beverages and juice samples

A novel magnetic metal organic framework composite (Fe3O4@MOF-808) was synthesized by a facile solvothermal method and applied as an adsorbent for the magnetic solid phase extraction (MSPE) of benzoylurea insecticides (BUs) from tea beverages and juice samples. The prepared materials were characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), vibrating sample magnetometry measurements and N2 adsorption-desorption experiments. The adsorption (adsorbent amount, extraction time and pH) and elution (elution solvent, elution volume and time) parameters were investigated in detail. Under the optimized experimental conditions, Fe3O4@MOF-808 exhibited simpler and better reusability than commercial C18, with an equivalent adsorption effect. Notably, π-π interactions, hydrophobic interactions and hydrogen bonding interactions contributed to the good adsorption of BUs by Fe3O4@MOF-808. Finally, a simple and sensitive method was established using Fe3O4@MOF-808-based MSPE coupled with high-performance liquid chromatography (HPLC). It provided low limits of detection (0.04–0.15 ng/mL), wide linear ranges (0.15–50 ng/mL) and satisfactory recoveries (84.6–98.3%). The proposed method was successfully applied for the fast and sensitive determination of BUs in tea beverages and juice samples.

Magnetic Metal–Organic Framework Composites: Solvent-Free Synthesis and Regeneration Driven by Localized Magnetic Induction Heat

Driven by the magnetic induction heat, a versatile solvent-free Magnetic Induction Framework Synthesis (sMIFS) route has been developed to synthesize magnetic metal–organic framework composites (MF...

Graphene-based magnetic metal organic framework nanocomposite for sensitive colorimetric detection and facile degradation of phenol

Abstract Phenol is a toxic and widely spread as environmental pollutants; the sensitive detection and efficient removal are quite important but challenging. Herein, we take the intrinsic advantages of graphene-based magnetic metal organic framework (MOF) composite as mimic enzyme sensor and Fenton-like catalyst for the colorimetric detection and degradation applications. In this work, magnetic Fe 3 O 4 decorated graphene MOF composite (Fe 3 O 4 /rGO/MOF) was fabricated by a simple strategy for the purpose of well-distributed porous MOF on basal planes of magnetic graphene. The adhesive coating of tannic acid film on both side of magnetic graphene was explored as the directing agent for the controllable self-assembly of MOF. Interestingly, the Fe 3 O 4 /rGO/MOF represent excellent mimic enzyme properties, which can detect phenol based on a visual colour change in water solution. The mimic enzyme senor can oxidize 4-aminoantipyrine in the presence of H 2 O 2 and exhibit strong affinity and selectivity in phenol detection. Simultaneously, Fe 3 O 4 /rGO/MOF also display high degradation ability towards phenol removal. These results indicate that the bifunctional composite can act both as colorimetric senor and Fenton-like catalyst, it would facilitate the real-time monitoring of water quality and wastewater treatment.

Nonderivatization method for determination of glyphosate, glufosinate, bialaphos, and their main metabolites in environmental waters based on magnetic metal-organic framework pretreatment.

A novel magnetic metal-organic framework composite was prepared by a self-assembly approach. The material properties were characterized by Fourier-transform infrared spectroscopy, vibrating sample magnetometry, thermogravimetry and differential thermogravimetric analysis, and X-photoelectron spectroscopy. Then, the as-prepared material was used as an adsorbent and indicated great enrichment ability toward glyphosate, glufosinate, bialaphos, and their main metabolites aminomethylphosphonic acid and 3-methylphosphinicopropionic acid. Based on this, an efficient magnetic solid-phase extraction method combined with ultra high performance liquid chromatography with high-resolution mass spectrometry for the pretreatment and determination of five target compounds in environmental waters was established. Parameters that could impact on the adsorption performance had been studied in detail. The proposed method was successfully applied for the simultaneous determination of glyphosate, glufosinate, bialaphos, and their main metabolites aminomethylphosphonic acid and 3-methylphosphinicopropionic acid in environmental water with recoveries in range of 86.2-104.6% with relative standard deviations less than 10%. Desired linearity was achieved varying from 1 to 100μg/L for five target analytes, respectively. The limits of detection were between 0.01 and 0.03μg/L.

Poly(deep eutectic solvent)-functionalized magnetic metal-organic framework composites coupled with solid-phase extraction for the selective separation of cationic dyes

Novel polymeric deep eutectic solvents (PDES) based on 3-acrylamidopropyl trimethylammonium chloride/D-sorbitol functionalized amino-magnetic (Fe3O4NH2) metal-organic framework (HKUST-1-MOF) composites (Fe3O4NH2@HKUST-1@PDES) were synthesized and characterized by field emission transmission electron microscope (FE-SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM) and zeta potentials. Then the composites were firstly utilized to selectively separate malachite green (MG) and crystal violet (CV) coupled with magnetic solid-phase extraction (MSPE). A response surface methodology (RSM) based on Latin hypercube sampling (LHS) was selected to analytically optimize the extraction parameters including initial concentration of dyes, extraction time, pH value and extraction temperature. The maximum extraction amount and optimal extraction conditions predicted by the RSM model matched well with the actual experimental results, and the extraction amount was 966.93 mg g−1 for MG and 788.90 mg g−1 for CV,respectively. The results indicated that the model possessed higher calculation accuracy through analyzing fewer sample points, thereby achieving theoretical prediction of extraction amount and conditions and being a prefect supplementary to actual experiments. The electrostatic interaction between the composites and cationic dyes played the main roll in the extraction process. The proposed extraction method exhibited lower limit of detection (98.19 ng mL−1 for MG and 23.97 ng mL−1 for CV) and preeminent precision (RSD ˂ 0.4%). Spiked recoveries of fish samples at three spiking levers ranged from 89.43% to 100.65% for MG and 95.29%–98.03% for CV. All results highlighted the excellent potential of Fe3O4NH2@HKUST-1@PDES-MSPE strategy in selective separation of cationic dyes in complex medium.

Synthesis of magnetic metal–organic framework composites, Fe3O4-NH2@MOF-235, for the magnetic solid-phase extraction of benzoylurea insecticides from honey, fruit juice and tap water samples

Herein, a novel, fusiform-like magnetic metal–organic framework material (Fe3O4-NH2@MOF-235) was fabricated by a facile two-step solvothermal approach.

Removal of Co(II) from aqueous solution with Zr-based magnetic metal-organic framework composite

The highly specific enrichment of 60Co from radioactive wastewater is the precondition of reducing radioactive contamination and ensuring the safety of watery environments. Herein, a novel glucose functionalized magnetic zirconium-based metal-organic framework (MOF) composite (Fe3O4@SiO2@UiO-66-Glu) was successfully prepared and utilized for the removal of Co(II) from aqueous solution. The effect of pH, contact time, initial Co(II) concentration, temperature and reusability had been explored. Results indicated that Co(II) adsorption reached equilibrium after eight hours, the maximum adsorption capacity of Fe3O4@SiO2@UiO-66-Glu for Co(II) was 178.6 mg g−1 at 288 K, 222.2 mg g−1 at 298 K, and 270.3 mg g−1 at 308 K. Besides, data obtained were fitted to Langmuir isotherm model, while the thermodynamic and kinetic parameters also showed that the adsorption process was spontaneous and endothermic by pseudo-second-order chemisorption. In addition, the synthesized composite displayed excellent regeneration availability in the recycle applications. As far as we know, this is the first time that magnetic MOFs are used exclusively for the separation of cobalt ions, which have the great potential to uptake 60Co from environmental wastewater.

Core-shell structured magnetic metal-organic framework composites for highly selective enrichment of endogenous N-linked glycopeptides and phosphopeptides

In this work, core-shell structured magnetic metal-organic framework composites denoted as Fe3O4 @MIL-100(Fe) were synthesized by means of a layer-by-layer assembly method selecting Fe as metal center and 1,3,5-benzenetricarboxylic acid as organic ligand. The as-prepared material exhibited outstanding sensitivity (0.1 fmol/μL), good selectivity (1:20 and 1:50 respectively), excellent ability of size-exclusion (1: 500), fine reusability (six cycles) and great stability (two months) in enriching N-linked glycopeptides and phosphopeptides from tryptic digests of standard proteins by combining HILIC and IMAC. Moreover, it was applied into the enrichment of endogenous N-linked glycopeptides and phosphopeptides in human saliva and achieved great results (43 phosphopeptides and 39 N-linked glycopeptides), revealing its promising potential in enrichment of low-abundance endogenous N-linked glycopeptides and phosphopeptides in practical samples.

Facile Fabrication of Magnetic Metal-Organic Framework Composites for the Highly Selective Removal of Cationic Dyes.

In this work, we show a novel magnetic composite material Fe3O4@HPU-9 (HPU-9 = {[Cd(L)0.5(H2O)](DMA)(CH3CN)}n) (H4L = 1,1′-di(3,5-dicarbonylbenzyl)-2,2′bimidazoline, DMA = N,N-dimethylacetamide) constructed by in situ growth of HPU-9 on Fe3O4, which has excellent absorption of cationic dyes from aqueous solution. The Fe3O4@HPU-9 particle possesses a well-defined core-shell structure consisting of a Fe3O4 core (diameter: 190 nm) and a HPU-9 shell (thickness: 10 nm). In the composite, the HPU-9 shell contributes to the capsulation of cationic dyes through electrostatic attractions between HPU-9 and cationic dyes, while the Fe3O4 core serves as magnetic particle. The maximum absorption capacity of Fe3O4@HPU-9 for R6G was 362.318 mg·g−1. The absorption kinetics data were well described by a psedo-second-order model (R2 > 0.99), and the equilibrium data were also well fitted to Langmuir isotherm model (R2 > 0.99). Our data confirmed that the proposed magnetic composite could be recycled and reused several times without centrifugal separation, making it more convenient, economic and efficient than common adsorbents.