Magnetic Metal-organic Framework Nanocomposite Research Articles

Enhanced Electrochemical Characterization of the Immune Checkpoint Protein PD-L1 using Aptamer-Functionalized Magnetic Metal-Organic Frameworks.

Programmed death ligand 1 (PD-L1) is highly expressed in cancer cells and participates in the immune escape process of tumor cells. However, as one of the most promising biomarkers for cancer immunotherapy monitoring, the key problem ahead of practical usage is how to effectively improve the detection sensitivity of PD-L1. Herein, an electrochemical aptasensor for the evaluation of tumor immunotherapy is developed based on the immune checkpoint protein PD-L1. The fundamental principle of this method involves the utilization of DNA nanotetrahedron (NTH)-based capture probes and aptamer-modified magnetic metal-organic framework nanocomposites as signaling probes. A synergistic enhancement is observed in the electrocatalytic effect between Fe3O4 and UiO-66 porous shells in Fe3O4@UiO-66 nanocomposites. Therefore, the integration of aptamer-modified Fe3O4@UiO-66@Au with NTH-assisted target immobilization as an electrochemical sensing platform can significantly enhance sensitivity and specificity for target detection. This method enables the detection of targets at concentrations as low as 7.76 pgmL-1 over a wide linear range (0.01 to 1000ngmL-1). The authors have successfully employed this sensor for in situ characterization of PD-L1 on the cell surface and for monitoring changes in PD-L1 expression during drug therapy, providing a cost-effective yet robust alternative to highly expensive and expertise-dependent flow cytometry.

Functionalized magnetic metal organic framework nanocomposites for high throughput automation extraction and sensitive detection of antipsychotic drugs in serum samples

Due to the complexity of biological sample matrix, the automated and high-throughput pretreatment technology is urgently needed for monitoring the antipsychotic drugs for mental patients. In this study, functionalized magnetic zirconium-based organic framework nanocomposites (Fe3O4@SiO2@Zr-MOFs) were successfully designed and synthesized by the layer-by-layer growth. Among them, Fe3O4@SiO2@UiO-67-COOH showed the best adsorption performance, and at the same time it exhibited excellent water dispersibility, high thermal stability, chemical stability and high hydrophobicity. Results of adsorption kinetics, isotherm and FT-IR showed that the adsorption process was dominated by chemical adsorption (hydrogen bond, electrostatic interaction, π-π interaction) and monolayer adsorption. Moreover, the smaller pore size improved the protein exclusion rate which reached 98.9–99.8%. Based on the above result, the synthesized magnetic nanoparticles were introduced to 96-well automatic extractor, antipsychotic drugs in 96 serum samples were automatically extracted within 9 min, which most greatly saved the time and labor costs and avoided artificial errors. By further integrating with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), antipsychotic drugs can be detected in the range of 0.2–3.0 ng mL−1 with a quantitative limit of 0.06–0.9 ng mL−1. The recoveries of antipsychotic drugs and their metabolites in serum ranged from 95.7% to 112.3% within 1.4–6.5% of RSD. These features indicate that the proposed method is promising for high throughput and sensitively monitoring of drugs and other hazardous substances.

Ag-based magnetic metal organic framework nanocomposite as catalyst for nitrophenol removal

In this work a silver based Magnetic Metal Organic Framework Nanocomposite (MMOFC) was prepared in which nanoparticles of magnetic iron oxide and nano Ag MOF of Ag-Benzene tricarboxylic acid form a nanostructure (IO@Ag-BTC). The synthesized nanostructure was characterized using XRD, SEM, EDS, TEM, TGA, IR and Raman spectroscopic techniques. The optical and morphological characterization confirmed the formation of a large number of low-symmetry spherical shaped particles of size ∼53 nm together with some rod-like shapes with aspect ratio ranging from 3.7 to 11.23. The potential of the synthesized IO@Ag-BTC MMOFCs towards the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) was demonstrated.

Magnetic dispersive solid-phase extraction based on magnetic metal-organic framework nanocomposite for the simultaneous detection of aflatoxins in edible oils

An efficient adsorbent composed of magnetic Fe3O4 particles and Al-based metal-organic framework (BUT-18) was prepared for magnetic dispersive solid-phase extraction (MDSPE) of four aflatoxins including B1, B2, G1, and G2 at trace amount in edible vegetable oils prior to analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Many parameters during MDSPE procedure such as amount of solvent used for extraction, extraction time, adsorbent amount, pH values, and desorption solvent were evaluated. Under optimal conditions, good limits of detections (LODs) and quantifications (LOQs) were achieved in the ranges of 0.1–0.4 μg/kg and 0.4–1.2 μg/kg, respectively. The established method was validated in terms of linearity (2–100 μg/kg) with correlation coefficient (R2 > 0.996). The recoveries of four aflatoxins in three oils spiked at three different concentrations (5, 10 and 20 μg/kg) were 70.1–90.73%, and the coefficient of variation was less than 6.54%. The developed approach demonstrates enormous potential for the determination of aflatoxins in real edible vegetable oils.

Selective extraction of apixaban from plasma by dispersive solid-phase microextraction using magnetic metal organic framework combined with molecularly imprinted polymer nanocomposite.

This research aims to synthesize a specific and efficient sorbent to use in the extraction of apixaban from human plasma samples and its determination by high-performance liquid chromatography-tandem mass spectrometry. High specific surface area of metal-organic framework, magnetic property of iron oxide nanoparticles, selectively of molecular imprinted polymer toward the analyte, and the combination of dispersive solid-phase extraction method with a sensitive analysis system provided an efficient analytical method. In this study, first, a molecularly imprinted polymer combined with magnetic metal organic framework nanocomposite was prepared and then characterized using different techniques. Then the sorbent particles were used for selective extraction of the analyte from plasma samples. The efficiency of the method was improved by optimizing effective parameters. According to the validation results, wide linear range (1.02-200ng mL-1 ), acceptable coefficient of determination (0.9938), low limit of detection (0.32ng mL-1 ) and limit of quantification (1.02ng mL-1 ), high extraction recovery (78%), and good precision (relative standard deviations ≤ 2.9% for intra- (n=6) and interday (n=6) precisions) were obtainable using the proposed method. These outcomes showed the high potential of the proposed method for screening apixaban in the human plasma samples.

Green synthesis of eco-friendly magnetic metal-organic framework nanocomposites (AlFum -graphene oxide) and pollutants (dye and pharmaceuticals) removal capacity from water

Herein, Graphene Oxide (GO), CoFe2O4, CoFe2O4/GO nanocomposite, aluminum fumarate (AlFum), and AlFum-CoFe2O4/GO (ACG) eco-friendly nanocomposites with different amounts of CoFe2O4/GO nanocomposite (5, 10, and 15 wt% denoted as 5ACG, 10ACG, and 15ACG, respectively) were green synthesized and characterized using FTIR, SEM, XRD, TEM, XRD, EDX, and BET. The XRD patterns of ACGs indicate that AlFum is fixed onto the surface of CoFe2O4/GO and its structure is well maintained. The SEM and TEM images indicated the 10ACG with good size distribution and shape. The EDX spectrum of ACG showed the homogeneous distribution of O, Fe, and Co in the synthesized materials. The synthesized ACG nanocomposite dispersed in water could be effortlessly separated from wastewater by an external magnet within several seconds. The dye (Direct Red 23: DR23) adsorption capacity of AlFum, 5ACG, 10ACG, and 15ACG was 120, 145, 230, and 167 mg/g, respectively. The Langmuir isotherm is a more adequate isotherm for characterizing the adsorption (R2 = 0.9998, 0.9918, 0.9997, and 0.9996 for AlFum, ACG-5, ACG-10, and ACG-15 respectively). Adsorption followed the pseudo-second-order kinetic. In addition, the synthesized composite had pharmaceuticals (tetracycline and doxycycline) removal ability.

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.

Synthesis of chitosan-modified magnetic metal-organic framework and its adsorption of Congo red and antibacterial activity

Although various nano-adsorbent have been developed for sewage treatment, only a few adsorbents possess antibacterial activities. We aimed to synthesis a double-purpose nano-adsorbent with adsorption and antibacterial activity. Magnetic composite materials (Fe3O4@ZIF-8@SiO2) with a porous crystalline state and large specific surface area were synthesized. Chitosan (CS) with broad-spectrum antimicrobial activity was used to functionalize the magnetic metal-organic framework nanocomposites. Fe3O4@ZIF-8@SiO2@CS were produced of low cost, mild conditions without any calcination step. Fourier transform infrared spectroscopy, scanning electron microscopy, the Brunauer-Emmett-Teller method, transmission electron microscopy, vibrating sample magnetometry, thermogravimetric analysis, X-ray diffractometry and X-ray energy dispersive spectrometry presented evidence that a new porous adsorbent Fe3O4@ZIF-8@SiO2@CS is rich in –NH2 and CS and have specific surface area of 420.58 m2/g. Fe3O4@ZIF-8@SiO2@CS has loose crystals, thermodynamically stable and well-defined structures, which are used for Congo red (CR) adsorption and bacterial cell killing. We determined optimal adsorption conditions by adjusting adsorption time, pH and ionic strength. Fe3O4@ZIF-8@SiO2@CS shows a good adsorption capacity of CR, reaching 310.4 mg/g at 298 K. The adsorption kinetics and adsorption isotherm obeyed the General-order kinetic (GO model) and Liu model, respectively. The Fe3O4@ZIF-8@SiO2@CS can remove dyes from simulated dye effluent, and it can be reproduced easily without centrifugation or filtration, with the adsorption efficiency exceeded 70% even after five cycles. Fe3O4@ZIF-8@SiO2@CS exhibited antibacterial activity against Staphylococcus aureus and Bacillus subtilis. Double-purpose Fe3O4@ZIF-8@SiO2@CS can be a potential material for wastewater treatment.

Preparation of Magnetic MIL-68(Ga) Metal-Organic Framework and Heavy Metal Ion Removal Application.

A magnetic metal–organic framework nanocomposite (magnetic MIL-68(Ga)) was synthesized through a “one pot” reaction and used for heavy metal ion removal. The morphology and elemental properties of the nanocomposite were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), X-ray powder diffraction (XRD), as well as zeta potential. Moreover, the factors affecting the adsorption capacity of the nanocomposite, including time, pH, metal ion type and concentration, were studied. It was found that the adsorption capacity of magnetic MIL-68(Ga) for Pb2+ and Cu2+ was 220 and 130 mg/g, respectively. Notably, the magnetic adsorbents could be separated easily using an external magnetic field, regenerated by ethylenediaminetetraacetic acid disodium salt (EDTA-Na2) and reused three times, in favor of practical application. This study provides a reference for the rapid separation and purification of heavy metal ions from wastewater.

Development of some magnetic metal–organic framework nano composites for pharmaceutical applications

• Some novel hydazone complexes were synthesized and characterized. • Antimicrobial activities of the titled compounds were screened. • Interaction of the prepared complexes with CT-DNA was investigated. • Antioxidant and Anticancer activities of the prepared compounds were checked. • Molecular Docking studies were employed to confirm the biological activity. A new series of un-doped and doped magnetite MIL-53 (Fe) series (MIL-53(Fe)/Fe 3 O 4 , MIL-53(Fe)/La-Fe 3 O 4 and MIL-53(Fe)/Gd-Fe 3 O 4 ) were prepared in one-step via solvothermal method. The investigated nanostructured MOFs were characterized by: Fourier Transform Infrared Spectroscopy (FT-IR) analysis, X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive X-ray analysis (EDX), Thermal gravimetric analysis (TGA), and the Nitrogen Adsorption. The results confirm that magnetic MIL-53 MOFs with uniformly distributed of doping ions (La and Gd) with high porosity was successfully prepared. Moreover, the synthesized compounds were evaluated for their in-vitro antimicrobial activity against three pathogenic bacterial strains and three pathogenic fungal strains. The investigated nanomaterials show potent antimicrobial activity against Serratia Marcescence bacteria and Getrichm Candidum fungi. Furthermore, in vitro toxicity of magnetite MIL-53 (Fe) series NPs was investigated on three different cell lines: MCF‐7 cell line (breast carcinoma), Hep-G2 cell line (hepatocellular carcinoma), and HCT-116 cell line (colon carcinoma). These nano MOFs had a high cytotoxic profile against breast cancer cells with IC 50 values up to 11.75 µg·mL 1 , ensuring adequate cell proliferation after 24 h.

Magnetic metal-organic framework (Fe3O4@ZIF-8) nanocomposites for adsorption of anionic dyes from wastewater

Since organic dyes are a major category of water contaminants, the processing of dye removal materials focuses on significant environmental significance. A metal organic structure adjusted by Fe3O4 nanoparticles (Fe3O4@MOF) has been easily synthesized and used as an adsorbent for the adsorption of Acid Red 57 (AR57) and Remazol Red (RR) anionic dyes and is used as a high-performance aqueous solution adsorbent. Fe3O4@ZIF-8, using a simple process, was synthesized at room temperature. The SEM, XRD, IR, and BET review described the Fe3O4@MOF as prepared. Fe3O4@MOF had a large specific area (475.3 m2/g), pore volume and pore size were also measured, X-ray diffraction spectroscopy (XRD), surface modification was measured using electron microscopy (SEM) scanning with a mean particle size of ∼248 nm in diameter, High chemical and thermal stability and high saturation magnetization (56.2 emu/g). Variables such as initial pH, adsorbent dosage, contact time and temperature have been studied in order to find optimal adsorption conditions for the extraction of Acid Red 57 (AR57) and Remazol Red (RR) from aqueous solutions. For the respective AR57 and RR, the optimal pH for extracting the anionic dyes tested from water solutions was 3 and 4. For AR57 and RR dyes, the overall predicted adsorption potential was 888.68 and 808.43 mgg−1, respectively, the effects of the initial solution pH, temperature, and, Initial concentration, contact time, salinity and dosing were systematically analyzed for Fe3O4@ZIF-8. These colors were ideal for acidic medium adsorption, where the zero-charge point (pHPZC) is equal to 4.3. The adsorption results were based on the isotherms of Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich adsorption. For both colors, the adsorption isotherm was found to obey the Lungmuir model. For AR57 and RR, the mean adsorption energy (Ea) is 20.24 and 31.3 kJmol−1, respectively, which indicates a phase of chemisorption. It was found that the kinetics of adsorption followed the pseudo-second-order kinetic model. The adsorption process was verified to be endothermic and random by thermodynamic experiments. The use of ethanol as the solvent was also studied in the method of desorption of the adsorbed anionic dyes.

Fast and efficient adsorption of palladium from aqueous solution by magnetic metal–organic framework nanocomposite modified with poly(propylene imine) dendrimer

In this study, a magnetic metal-organic framework (MMOF) was synthesized and post-modified with poly(propyleneimine) dendrimer to fabricate a novel functional porous nanocomposite for adsorption and recovery of palladium (Pd(II)) from aqueous solution. The morphological and structural characteristics of the prepared material were identified by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmet-Teller (BET) isotherm, and vibrating sample magnetometer (VSM). The results confirmed the successful synthesis and post-modification of MMOF. Semispherical shape particles (20-50 nm) with appropriate magnetic properties and a high specific surface area of 120 m2/g were obtained. An experimental design approach was performed to show the effect of adsorption conditions on Pd(II) uptake efficiency of the dendrimer-modified magnetic adsorbent. The study showed that the Pd(II) uptake on dendrimer-modified MMOF was well described by the Langmuir isotherm model with the highest uptake capacity of 291 mg/g under optimal condition (adsorbent content of 12.5 mg, Pd ion concentration of 80 ppm, pH = 4, and contact time of 40 min). The adsorption kinetics of Pd(II) ions was suggested to be a pseudo-first-order model. The results revealed a faster adsorption rate and higher adsorption capacity (about 43%) for dendrimer-modified MMOF. Finally, the reusability of the provided adsorbent was evaluated. This work provides a valuable strategy for designing and developing efficient magnetic adsorbents based on MOFs for the adsorption and recovery of precious metals.

Carnosine functionalized magnetic metal–organic framework nanocomposites for synergistic enrichment of phosphopeptides

Protein phosphorylation regulates the conformations and function of proteins, which plays an important part in organisms. However, systematic and in-depth analysis of phosphorylation often hinders on account of the low abundance and suppressed ionization of phosphopeptides. Various materials based on single enrichment mechanism show potential in phosphopeptides enrichment, but the enrichment performance is typically not satisfactory. Herein, we developed a carnosine (Car) functionalized magnetic metal organic framework designed as Fe3O4@NH2@ZIF-90@Car. Benefiting from the multiple recognition groups of Car and massive metal ions site of ZIF-90, the as-fabricated Fe3O4@NH2@ZIF-90@Car was utilized as a multifunctional material with synergistic effect for phosphopeptides enrichment. On the basis of combined immobilized metal ion affinity chromatography (IMAC) and amine-based affinity enrichment mechanism, Fe3O4@NH2@ZIF-90@Car exhibited higher enrichment performance of phosphopeptides compared with Fe3O4@NH2@ZIF-90 (single IMAC mechanism). Besides, the feasibility of Fe3O4@NH2@ZIF-90@Car nanocomposites in complicated samples was further verified by enriching phosphopeptides from nonfat milk, human fluids such as serum and saliva, demonstrating its bright application prospects in phosphoproteomics analysis.

Ionic Liquid-Functionalized Magnetic Metal-Organic Framework Nanocomposites for Efficient Extraction and Sensitive Detection of Fluoroquinolone Antibiotics in Environmental Water.

Herein, the hydrophobic carboxyl-functionalized ionic liquid (IL-COOH) was encapsulated into the prepared Fe3O4@Zr-MOFs, and the novel water-stable IL-COOH/Fe3O4@Zr-MOF nanocomposites were first synthesized. The polydopamine-functionalized Fe3O4 was introduced to construct the core-shell structure via layer-by-layer modification, and the controlled growth of Zr-MOFs was achieved, which realized the adjustment of charged properties of nanocomposites and simplified the adsorption or extraction process. The IL-COOH/Fe3O4@Zr-MOFs were fully studied by IR, HNMR, XRD, N2 adsorption-desorption isotherms, TEM, EDS mapping, VSM, and so on. Then, they were employed for the selective adsorption and detection of fluoroquinolone antibiotics (FQs). The adsorption isotherms and kinetics demonstrated that the adsorption process followed a pseudo-second-order kinetic model and the Langmuir isotherm model. Among them, IL-COOH/Fe3O4@UiO-67-bpydc showed the best adsorption performance, and the maximum adsorption capacity of ofloxacin was 438.5 mg g-1. Coupled magnetic solid-phase extraction with HPLC-DAD, a convenient, sensitive, and efficient method for extraction and detection of FQs in environmental water, was developed based on IL-COOH/Fe3O4@UiO-67-bpydc. The recoveries of environmental water were ranging from 90.0 to 110.0%, and the detection limits were lower than 0.02 μg L-1. The novel functionalized composites served as solid-phase adsorbents and liquid-phase extractants. This study also provided a promising strategy for designing and preparing multi-functionalized nanocomposites for the removal or detection of pollutants in environmental samples.

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.

Magnetic metal-organic frameworks containing abundant carboxylic groups for highly effective enrichment of glycopeptides in breast cancer serum

A mercaptosuccinic acid functionalized hydrophilic magnetic metal-organic framework nanocomposite (denoted as mMOF@Au-MSA) was proposed and synthesized to provide an excellent platform for glycopeptide analysis. The novel nanomaterial integrated favorable advantages such as robust magnetic response from Fe3O4 magnetic nanoparticles, large surface area contributed by MOF, abundant ultra-high hydrophilic carboxylic groups from mercaptosuccinic acid, as well as unbiased affinity toward different types of glycopeptides. This nanocomposite was successfully utilized to capture glycopeptides from standard protein digests with the high selectivity and great sensitivity of 0.5 fmol μL−1. Notably, 307 glycopeptides assigned to 96 glycoproteins were identified from only 2 μL serum of breast cancer patient. The satisfying achievement indicated that the as-prepared nanopartical had promising potential in exploring the knowledge of glycoproteins in breast cancer.

In situ deposition of Ag/AgCl on the surface of magnetic metal-organic framework nanocomposite and its application for the visible-light photocatalytic degradation of Rhodamine dye.

Herein, NH2-MIL-125(Ti) (NMT) as one of the known stable metal-organic frameworks (MOFs) in aqueous solution was successfully magnetized with CoFe2O4 nanoparticles through the hydrothermal method. The Ag/AgCl as a plasmonic photocatalyst was assembled on the CoFe2O4/NMT (CFNMT) at room temperature by in situ deposition, and photo-reduction methods to improve the photocatalytic activity of CFNMT under LED visible light. The prepared materials were fully characterized by SEM/EDX, TEM, FTIR, XRD, UV-DRS, and VSM analysis. Rhodamin B (RhB) was selected as the pollutant model. The results showed that the Ag/AgCl@CFNMT had super-fast degradation ability of RhB molecule due to the synergetic effect between Ag/AgCl and CFNMT in comparison with NMT and CFNMT. The introduced Ag/AgCl on the surface of CFNMT increased absorption of photons in the visible region and enhanced the transfer and separation of the produced charge on the contact area between Ag/AgCl and CFNMT. Also, after seven times recycling, besides the simple magnetic separation of Ag/AgCl@CFNMT from liquid media, the composite still showed high photodegradation ability (89%).

Highly efficient removal of toxic lead ions from aqueous solutions using a new magnetic metal‐organic framework nanocomposite

A magnetic metal‐organic framework (MOF) nanocomposite was successfully prepared by a new and green strategy through reasonable design. Magnetic MOF of Fe3O4‐NHSO3H@HKUST‐1 nanocomposite use for removal of lead ions as an environmental pollutant. The experimental results indicated that the nano adsorbent of Fe3O4‐NHSO3H@HKUST‐1 can removed lead ions under optimum operational conditions. The dosage of the nanocomposite, pH of the sample solution, and contact time were obtained to be 10 mg, 7.0, and 90 min, respectively, while the initial concentration of Pb(II) ions of 400 mg/L was used. A kinetic study indicated that a pseudo‐second‐order model agreed well with the experimental data. The isotherm experiments revealed that the Langmuir model attained better fits to the equilibrium data than the Freundlich model. The maximum adsorption capacity of the adsorbent for the removal of lead under the optimum operational conditions of pH 7.0 and temperature 25°C was found to be 384.6 mg/g. The thermodynamic parameters indicate that the adsorption of lead is spontaneous and endothermic. The magnetic MOF nanocomposite could be recovered easily and reused many times without significant loss of its nano‐adsorbent activity. The proposed method is simple, eco‐friendly, low cost, and efficient in the removal of lead ions from aqueous solutions.

Bio-based magnetic metal-organic framework nanocomposite: Ultrasound-assisted synthesis and pollutant (heavy metal and dye) removal from aqueous media

In the recent decade, Metal-Organic Frameworks (MOFs) and their most popular subclasses (zeolitic imidazolate frameworks (ZIFs)) are widely studied for removing contaminants from the effluent. Herein, the magnetic bionanocomposite (eggshell membrane-zeolitic imidazolate framework) was synthesized using a facile, efficient, and green ultrasound-assisted method. Zeolitic imidazolate frameworks-67 (ZIF-67) crystals were stabilized on the surface of magnetic eggshell membrane (Fe3O4@ESM) support to prepare the ZIF-67@ Fe3O4@ESM composite as a novel adsorbent with the high surface area (1263.9 m2/g). Several analyses such as XRD, FTIR, SEM/EDS/Mapping, VSM, and BET were used to confirm the characterization and structural changes of ZIF-67 crystals before and after the composition process. Thereafter, copper cation (Cu2+) capture and dye (Basic Red 18: BR18) adsorption process were designed and thoroughly studied using the prepared adsorbents. It was found that the adsorption rate and removal percentage of the ZIF-67@Fe3O4@ESM composite are faster and higher than that of the pure ZIF-67 for both types of contaminants. Moreover, the magnetic feature of the composite adsorbent caused to a facile separation from liquid media. The results showed that the Langmuir adsorption isotherm well explained the obtained equilibrium data with a maximum adsorption capacity of 344.82 and 250.81 mg/g for Cu2+ and BR18, respectively. Kinetic studies showed that the pseudo-second order model was capable to fit the experimental data of the simultaneous removal of heavy metal ion and dye molecule.

CoFe2O4/TMU‐17‐NH2 as a hybrid magnetic nanocomposite catalyst for multicomponent synthesis of dihydropyrimidines

A new magnetic metal–organic framework nanocomposite (CoFe2O4/TMU‐17‐NH2) was prepared via an embedding approach by synthesis of the metal–organic framework crystals in the presence of magnetic cobalt ferrite nanoparticles. We demonstrated that the resulting magnetic nanocomposite can serve as a recyclable nanocatalyst for one‐pot synthesis of bis‐3,4‐dihydropyrimidin‐2(1H)‐one and 3,4‐dihydropyrimidin‐2(1H)‐one derivatives via three‐component reaction of 1,3‐diketone, urea or thiourea and aromatic aldehyde under solvent‐free conditions. CoFe2O4/TMU‐17‐NH2 was characterized using various techniques. The recovery of the nanocomposite was achieved by a simple magnetic decantation and it was reused at least seven times without significant degradation in catalytic activity.