Framework Nanocomposite Research Articles

Confined polymerization strategy to construct polypyrrole/zeolitic imidazolate frameworks (PPy/ZIFs) nanocomposites for tunable electrical conductivity and excellent electromagnetic absorption

Electrically conductive porous metal-organic frameworks (MOFs) exhibit a huge potential in a broad range of applications. However, how to endow MOFs with appropriate electrical conductivity remains a challenge. In this paper, we report a controllable growth of polypyrrole (PPy) nanofibers in the nanochannels of MOFs to construct a kind of nanocomposites. We can also use this strategy to directly demonstrate the straight nanochannel structure in MOFs. More importantly, the formed PPy/ZIFs nanocomposites show a highly tunable electrical conductivity as well as a tunable electromagnetic absorption (EMA) property. The maximal frequency width with absorbing higher than 90% of incident electromagnetic waves reaches 7.24 GHz, which is wider than those of most reported MOFs or conducting polymers based EMA materials. An electrical conductance loss and interfacial polarization relaxation are used to investigate the electromagnetic dissipation mechanism of theses PPy/ZIFs nanocomposites. It opens up the rational design of electrically conductive MOFs for excellent electromagnetic absorption.

Tandem magnetization and post‐synthetic metal ion exchange of metal–organic framework: Synthesis, characterization and catalytic study

For the first time, metal‐exchange in a magnetic metal–organic framework (MOF) via tandem magnetization and post‐synthetic modification has been developed. The new magnetic mixed‐metal metal–organic framework nanocomposite, CoFe2O4/[Cu0.63/Zn0.37‐TMU‐17‐NH2] (CoFe2O4/[Cu/Zn‐MOF]) has been synthesized by immersing the CoFe2O4/Zn‐TMU‐17‐NH2 (CoFe2O4/Zn‐MOF) as a template in DMF solution of Cu (II) salts. CoFe2O4/[Cu/Zn‐MOF] showed to be a highly reactive and easily recoverable magnetic catalyst for the preparation of tetrazole derivatives via one‐pot three‐component reactions of different aldehydes with hydroxyl amine hydrochloride and sodium azide. Our results (Fourier transform‐infrared, inductively coupled plasma‐optical emission spectroscopy, powder X‐ray diffraction, field emission‐scanning electron microscopy, energy‐dispersive X‐ray spectroscopy‐mapping and vibrating‐sample magnetometer) show successful partial metal‐exchange in which the framework integrity remained intact during the metal‐exchange process.

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.

Magnetic bio-metal–organic framework nanocomposites decorated with folic acid conjugated chitosan as a promising biocompatible targeted theranostic system for cancer treatment

In this work, a multifunctional magnetic Bio-Metal-Organic Framework (Fe3O4@Bio-MOF) coated with folic acid-chitosan conjugate (FC) was successfully prepared for tumor-targeted delivery of curcumin (CUR) and 5-fluorouracil (5-FU) simultaneously. Bio-MOF nanocomposite based on CUR as organic linker and zinc as metal ion was prepared by hydrothermal method in the presence of amine-functionalized Fe3O4 magnetic nanoparticles (Fe3O4@NH2 MNPs). 5-FU was loaded in the magnetic Bio-MOF and the obtained nanocarrier was then coated with FC network. The prepared nanocomposite (NC) was fully characterized by high resolution-transmission electron microscope (HR-TEM), field emission scanning electron microscopy (FE-SEM), Dynamic light scattering (DLS), X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), nuclear magnetic resonance (NMR), and UV–vis analyses. In vitro release study showed controlled release of CUR and 5-FU in acidic pH confirming high selectivity and performance of the carrier in cancerous microenvironments. The selective uptake of 5-FU-loaded Fe3O4@Bio-MOF-FC by folate receptor-positive MDA-MB-231 cells was investigated and verified. The ultimate nanocarrier exhibited no significant toxicity, while drug loaded nanocarrier showed selective and higher toxicity against the cancerous cells than normal cells. SDS PAGE was also utilized to determine the protein pattern attached on the surface of the nanocarriers. In vitro and in vivo MRI studies showed negative signal enhancement in tumor confirming the ability of the nanocarrier to be applied as diagnostic agent. Owing to the selective anticancer release and cellular uptake, acceptable blood compatibility as well as suitable T2 MRI contrast performance, the target nanocarrier could be considered as favorable theranostic in breast cancer.

Novel magnetic amine functionalized carbon nanotube/metal-organic framework nanocomposites: From green ultrasound-assisted synthesis to detailed selective pollutant removal modelling from binary systems.

Herein, magnetic amine functionalized carbon nanotube (NH2-CNT/Fe2O3)-zeolitic imidazolate framework-8 (ZIF-8) nanocomposites (NH2-CNT/Fe2O3/ZIF-8: NCFZ) with different amounts of NH2-CNT/Fe2O3 (5, 10, and 15 wt% denoted as NCFZ-5, NCFZ-10, and NCFZ-15) were synthesized. The synthesized nanomaterials including ZIF-8, Fe2O3, CNT/Fe2O3, NH2-CNT/Fe2O3, CNT/Fe2O3/ZIF-8, NCFZ-5, NCFZ-10, and NCFZ-15 were characterized using BET, TEM, XRD, SEM, FTIR, VSM and zeta potential. The synthesized nanomaterials were applied for selective removing cationic dyes (MG: Malachite Green and RhB: Rhodamine B) from a binary system. Response surface methodology (RSM) and artificial neural networks (ANN) were used for optimizing dye removal. The BET data showed that the surface area of nanocomposite (NH2-CNT/Fe2O3/ZIF-8: 1659 m2/g) was higher than that of pure ZIF-8 (1485 m2/g). Contaminant removal obeyed the Freundlich isotherm and pseudo-second order kinetic models. The optimum adsorption condition predicted by RSM was pH = 6, dye concentration = 25 mg/L, Dosage = 0.004 g and at time = 145 min. The outputs of ANN model well overlapped with the experimental data. The binary system dye removal data indicated the synthesized nanocomposite with recycling and regeneration ability could be used for treating wastewater.

A nanocomposite consisting of an amorphous seed and a molecularly imprinted covalent organic framework shell for extraction and HPLC determination of nonsteroidal anti-inflammatory drugs.

A novel nanocomposite consisting of an amorphous seed and a molecularly imprinted covalent organic framework shell was prepared via a heterogeneous nucleation and growth method. By using ibuprofen as the dummy template, a molecularly imprinted covalent organic framework (MICOF) with a large surface area was prepared from 1,3,5-triformylbenzene and 4,4'-diaminobiphenyl. It was placed on the surface of monodisperse amorphous seeds. Owing to strong π-interaction, the MICOF@SiO2 nanocomposite displays fast binding kinetics, large adsorption capacities and selectivity for nonsteroidal anti-inflammatory drugs (NSAIDs). Following desorption from the MICOF@SiO2 with methanol containing 1% ammonium hydroxide, the NSAIDs ketoprofen, ibuprofen, diclofenac, indomethacin, flurbiprofen and naproxen were quantified by HPLC with UV detection. Under optimized conditions, the method exhibits good linearity within the range of 0.002-1.0μgmL-1, low limits of detection (0.38-2.92μgL-1), and acceptable repeatability. The recoveries of NSAIDs at three spiking levels range from 77 to 112%, and the RSDs are <9.4%. The method was successfully applied to the analysis of NSAIDs in spiked environmental water samples. Graphical abstract A molecular imprinted covalent organic framework nanocomposite (MICOF@SiO2) was prepared by heterogeneous nucleation and growth method. It was explored as a sorbent for the solid phase extraction of nonsteroidal anti-inflammatory drugs before determination by HPLC with UV detection.

Activated carbon/metal-organic framework nanocomposite: Preparation and photocatalytic dye degradation mathematical modeling from wastewater by least squares support vector machine

Herein, Kiwi peel activated carbon (AC), Materials Institute Lavoisier (MIL-88B (Fe), and AC/MIL-88B (Fe) composite were synthesized and used as catalysts to degrade Reactive Red 198. The material properties were analyzed by the FTIR, BET-BJH, XRD, FESEM, EDX, TGA, and UV–Vis/DRS. The BET surface area of AC, MIL-88B (Fe) and AC/MIL-88B (Fe) was 1113.3, 150.7, and 199.4 m2/g, respectively. The band gap values (Eg) estimated by Tauc plot method, were obtained 5.06, 4.19 and 3.79 eV for AC, MIL-88B (Fe) and AC/MIL-88B (Fe), respectively. The results indicated that the AC/MIL-88B (Fe) composite had higher photocatalytic activity (99%) than that of pure AC (79%) and MIL-88B (Fe) catalysts (87%). The decolorization kinetic was matched well with the second-order model. Moreover, the data were modeled using least squares support vector machine which optimized with Cuckoo optimization algorithm. The optimal parameters were found 0.837 and 3.49e+02 based on σ2 and γ values, respectively. The mean square error (MSE) and correlation coefficient (R2) values were obtained 3.97 and 0.948. Therefore, the attained data, materials characterization and prediction of modeling validate the composite form of MIL-88B(Fe) with new AC, had better photocatalytic activity in comparison with the individual form.

A dual-zwitterion functionalized ultra-hydrophilic metal-organic framework with ingenious synergy for enhanced enrichment of glycopeptides.

A rational strategy was introduced for the synthesis of a novel dual functionalized metal-organic framework nanocomposite (AuGC/ZIF-8) with ultra-hydrophilicity to enhance glycopeptide enrichment. The advantages of ingenious synergy, low-cost, facile and large-scale synthesis, and excellent enrichment performance will enable it to have a bright future in nanomaterial synthesis, glycoproteomics analysis, and related biochemistry.

A molybdenum disulfide and 2D metal-organic framework nanocomposite for improved electrocatalytic hydrogen evolution reaction

The development of electrochemically active nanocomposites with excellent hydrogen evolution reaction (HER) is of great significance for clean energy utilization. Herein, a MoS2/Co-MOF nanocomposite assembled from MoS2 and 2D Co-MOF have been prepared through weak interactions. The optimized nanocomposite exhibits enhanced HER activity, including the lower overpotential (262 mV) and the smaller Tafel slope (51 mV·dec−1), which is attributed to the increased electrochemically active surface area, nanointerface engineering, and the synergistic effect between Co-MOF and MoS2.

Carbon nanotube based metal-organic framework nanocomposites: Synthesis and their photocatalytic activity for decolorization of colored wastewater

Herein, Materials Institute Lavoisier (MIL-125(Ti))/carbon nanotube (CNT) nanoporous composites (MIL/CNT) were synthesized by hydrothermal method. Different amounts of CNT (0.01 g and 0.03 g) were used to synthesize nanocomposites (denoted as MIL/CNT(0.01) and MIL/CNT(0.03), respectively). The synthesized nanomaterials (MIL, MIL/CNT(0.01) and MIL/CNT(0.03)) were characterized by XRD, FTIR, TGA, BET, SEM, and zeta potential and used for photocatalytic dye degradation. Reactive Black 5 (RB5) was used as a model pollutant. The zeta potential of MIL and MIL/CNT (0.01) were −27.7 mV and 19.2 mV, respectively. The data showed that that MIL/CNT(0.01) nanocomposite had higher photocatalytic dye degradation due to the synergistic effect of CNT. Dye decolorization by the nanomaterials followed the zero-order kinetics reaction. The decolorization rate was 0.0015, 0.0019, 0.0024 mg/L min for MIL, MIL/CNT(0.01) and MIL/CNT(0.03), with the correlation coefficient of 0.9639, 0.9906, and 0.9757, respectively. The synthesized catalysts were reusable over two cycles.

Preparation of amine functionalized g-C3N4@H/SMOF NCs with visible light photocatalytic characteristic for 4-nitrophenol degradation from aqueous solution.

At ambience temperature, a facile and large-scale sonochemical synthesis route was used to synthesize graphitic carbon nitride@[Ti4C24H39N3O29] metal-organic framework nanocomposites (g-C3N4-X@YTi-MIL125-NH2 NCs, where X and Y stood for the weight percentages of g - C3N4 and the synthesis method of Ti-MIL125-NH2, respectively) having 2-Amino-1,4-benzenedicarboxylic acid (2-ATA) ligand with amine functional free groups. The obtained NCs were characterized by FT-IR, PXRD, FE-SEM, BET, UV-DRS, PL, EIS, and zeta potential. Moreover, g-C3N4-X@YTi-MIL125-NH2 capability to eliminate 4-nitrophenol (4-NP) contaminant from water via visible light illumination was explored. Our synthesized NCs under a facile, green ultrasonic technique (i.e. g-C3N4-30@STi-MIL125-NH2) had a higher percentage of degradation than those from hydrothermal technique (i.e. g-C3N4-30@HTi-MIL125-NH2) with degradation percentages of 75% and 57%, respectively, which resulted in effective mass transfer and separation of photo - generated charge carriers. Additionally, this higher percentage of degradation could be attributed to the larger surface area and unique morphology of the ultrasonically synthesized particles with higher homogeneity and better and non-agglomerated distribution. Furthermore, excellent reusability and stability were observed for g-C3N4-30@STi-MIL125-NH2. We also explored the role of some scavengers in the degradation procedures to investigate the effect of active species. The experimental results were used to describe the suggested mechanism capability for improved photocatalysis.

Synthesis of NENU metal-organic framework-graphene oxide nanocomposites and their pollutant removal ability from water using ultrasound

The cleaner production of metal-organic framework nanocomposite includes room/low temperature synthesis and the use of harmless solvents. In this paper, metal-organic framework (NENU: Northeast Normal University) - graphene oxide (GO) nanocomposites (NENU/GO) with different amounts of GO (0.005, 0.01, 0.015, 0.02 and 0.03 g denoted as NENU/0.005GO, NENU/0.01GO, NENU/0.015GO, NENU/0.02GO and NENU/0.03GO, respectively) were synthesized at room temperature using ethanol as a harmless solvent. The pollutant (dye) removal ability of the materials from water was studied in details. The GO nanosheet was prepared from graphite. The synthesized nanomaterials were characterized using Brunauer–Emmett–Teller, X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, transmission electron microscopy, and zeta potential. Dye removal at 5, 10 and 20 mg/L of dye concentration was 87, 84 and 59%, respectively. The pollutant adsorption capacity of the NENU, NENU/0.005GO, NENU/0.01GO, NENU/0.015GO, NENU/0.02GO and NENU/0.03GO was 125, 130, 151, 170, 183 and 243 mg/g, respectively. The pollutant uptake data confirmed the Freundlich isotherm and pseudo-second order kinetics.

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.

Magnetic metal-organic framework nanocomposites for enrichment and direct detection of environmental pollutants by negative-ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Nowadays, the detection and removal of environmental pollutants are particularly important, owing to their harmful influence on human beings’ health. Specifically, metal-organic frameworks (MOFs) as the hot materials with great potential have been widely employed as adsorbents for pollutants removal, as well as matrixes for mass spectrometry detection. In this work, magnetic Zr-based MOF (denoted as Fe3O4@PDA@ZrMOF) with outstanding properties, such as low background interference, high desorption/ionization efficiency, excellent signal reproducibility, ultrahigh surface area and strong magnetic responsiveness, was synthesized by a modified thermal annealing method. The Fe3O4@PDA@ZrMOF not only can be utilized as adsorbent towards small molecules by π-π stacking interaction between nitrophenols and ZrMOF, but also can serve as a matrix for detection of small molecules under the negative ion mode of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). As a result, with the use of Fe3O4@PDA@ZrMOF, the detection limits of 4-nitrocatechol and 4-nitroguaiacol were estimated to be about 68 μg/ml and 25 μg/ml, respectively. In addition, enrichment of nitrophenols from PM2.5 was investigated. The detected mass concentrations of 4-nitrocatechol and 4-nitroguaiacol in collected PM2.5 samples were 0.11 ng/m3 and 0.15 ng/m3, respectively, indicating the highly efficient enrichment performance of Fe3O4@PDA@ZrMOF for low-abundance nitrophenol compounds in the environment.

Preparation and characterization of magnetic metal–organic framework nanocomposite as solid-phase microextraction fibers coupled with high-performance liquid chromatography for determination of non-steroidal anti-inflammatory drugs in biological fluids and tablet formulation samples

A novel solid-phase microextraction (SPME) fiber based on a capillary glass tube coated with magnetic Fe3O4/Cu3(BTC)2 metal organic frameworks nanocomposite was prepared by sol–gel technique. The magnetic Fe3O4/Cu3(BTC)2 metal organic frameworks nanocomposite were synthesized by a simple hydrothermal reaction and the resultant powder was mixed with sol–gel precursors to prepare sol–gel solution of the magnetic Fe3O4/Cu3(BTC)2 coating material. In this study, glass tubes with a specific diameter were used as substrates. The magnetic Fe3O4/Cu3(BTC)2 MOF nanocomposites coating was characterized using Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). Then, the synthesized fiber as novel solid-phase microextraction (SPME) fiber combined with high-performance liquid chromatography (SPME–HPLC) was applied for the determination and quantification of non-steroidal anti-inflammatory drugs (NSAIDs) (ibuprofen, diclofenac, naproxen and nalidixic acid) in real samples including human urine, serum, plasma, and tablet formulation. To found optimum microextraction conditions, the influences of effective variables were investigated using one-factor-at-a-time experiments and the significant variables were optimized using a Box–Behnken design (BBD) combined with desirability function. Under optimized conditions, calibration graphs of analytes were linear in a concentration range of 0.1–400 μg L−1 with correlation coefficients >0.9966. Limits of detection and quantification were in the ranges of 0.03–0.0 5 μg L−1 and 0.12–0.18 μg L−1, respectively. This procedure was successfully employed in determining target analytes in spiked human urine, serum, plasma, and tablet samples with recoveries ranged from 94.0 to 102.0%.

Visual detection of peroxide-based explosives using novel mimetic Ag nanoparticle/ZnMOF nanocomposite

A simple and selective colorimetric method for the detection of perilous peroxide explosives was developed using the peroxidase mimetic activity of silver nanoparticles/flake-like zinc metal-organic framework nanocomposite (Ag@ZnMOF). The synthesis of Ag@ZnMOF contained the formation of silver nanoparticles (AgNPs) inside the fine pores of Zn metal-organic framework (ZnMOF). High reactive AgNPs as well as great surface area of MOFs provided a synergetic and high improved catalytic activity for the composite which was studied as a peroxidase mimic in hydrogen peroxide (H2O2)-based oxidations. The achieved system was used for detection of Triacetone triperoxide (TATP) as one of the most hazardous peroxide explosives. TATP was decomposed in an acidic condition to generate H2O2, which was then applied to oxidize 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of the Ag@ZnMOF as a catalyst. This reaction led to the production of well-known blue colored charge transfer complex (oxTMB), which was recognized by the colorimetric technique. A linear relationship was obtained between the absorption intensity of the produced blue solution and the TATP concentration in the range of 0.4-15 mg L-1, with a detection limit of 0.1 mg L-1. A portable test kit was prepared using the same reagents for TATP measurement in real samples.

Water-dispersible PEG-curcumin/amine-functionalized covalent organic framework nanocomposites as smart carriers for in vivo drug delivery

Covalent organic frameworks (COFs) as drug-delivery carriers have been mostly evaluated in vitro due to the lack of COFs nanocarriers that are suitable for in vivo studies. Here we develop a series of water-dispersible polymer-COF nanocomposites through the assembly of polyethylene-glycol-modified monofunctional curcumin derivatives (PEG-CCM) and amine-functionalized COFs (APTES-COF-1) for in vitro and in vivo drug delivery. The real-time fluorescence response shows efficient tracking of the COF-based materials upon cellular uptake and anticancer drug (doxorubicin (DOX)) release. Notably, in vitro and in vivo studies demonstrate that PEG-CCM@APTES-COF-1 is a smart carrier for drug delivery with superior stability, intrinsic biodegradability, high DOX loading capacity, strong and stable fluorescence, prolonged circulation time and improved drug accumulation in tumors. More intriguingly, PEG350-CCM@APTES-COF-1 presents an effective targeting strategy for brain research. We envisage that PEG-CCM@APTES-COF-1 nanocomposites represent a great promise toward the development of a multifunctional platform for cancer-targeted in vivo drug delivery.

Solution-Phase Synthesis of Platinum Nanoparticle-Decorated Metal-Organic Framework Hybrid Nanomaterials as Biomimetic Nanoenzymes for Biosensing Applications.

The synthesis of nanomaterials with specific properties and functions as biomimetic nanoenzymes has attracted extensive attention in the past decades due to their great potential to substitute natural enzymes. Herein, a facile and simple method for the preparation of platinum nanoparticle (PtNP)-decorated two-dimensional metal-organic framework (MOF) nanocomposites was developed. A ligand with heme-like structure, Fe(III) tetra(4-carboxyphenyl)porphine chloride (TCPP(Fe)), was applied to synthesize MOF nanosheets (denoted as Cu-TCPP(Fe) nanosheets) in high yield. Ultrathin Cu-TCPP(Fe) nanosheets with thickness less than 10 nm were used as a novel template for the growth of ultrasmall and uniform PtNPs. Significantly, the obtained hybrid nanomaterials (PtNPs/Cu-TCPP(Fe) hybrid nanosheets) exhibit enhanced peroxidase-like activity compared to PtNPs, Cu-TCPP(Fe) nanosheets, and the physical mixture of both due to the synergistic effect. On account of the excellent peroxidase-like activity of PtNPs/Cu-TCPP(Fe) hybrid nanosheets, we established a colorimetric method for sensitive and rapid detection of hydrogen peroxide. Furthermore, by combining with glucose oxidase, a cascade colorimetric method was established to further detect glucose with excellent sensitivity and selectivity.

Synthesis of magnetic metal-organic framework nanocomposite (ZIF-8@SiO2@MnFe2O4) as a novel adsorbent for selective dye removal from multicomponent systems

Herein, magnetic metal-organic framework nanocomposite (ZIF-8@SiO2@MnFe2O4) was synthesized. The ultrasound-assisted simultaneous adsorption of Malachite Green (MG) and Methyl Orange (MO) as cationic and anionic dyes onto ZIF-8@SiO2@MnFe2O4 magnetic microporous nanocomposite (MMNC) as a novel adsorbent was investigated. The FTIR, FESEM, TEM, XRD, BET and VSM were used to characterize the prepared adsorbent. The analysis of dyes concentration in a binary mixture was investigated using zero-order and first order derivative spectrophotometry. The individual effects and possible interactions between the various parameters were investigated by response surface methodology (RSM). The optimized values of sonication time, adsorbent mass, MG and MO concentrations were found to be 15 min, 0.005 g, 13 and 10 mg L−1, respectively. The removal percentages for MG and MO were predicted to be 92.5% and 5.9%, respectively. The data matched well with pseudo-second order kinetic model and Langmuir isotherm models. The maximum adsorption capacities were obtained 1010.2 and 78.12 mg g−1 for MG and MO dyes, respectively. Moreover, the magnetic nanocomposite showed that it could selectively adsorbed cationic MG dye from the MG/MO mixture. After reaction, the magnetic adsorbent can be easily separated from the mixture via an external magnetic field and can be effectively regenerated.

The Cooperativity of Fe3 O4 and Metal-Organic Framework as Multifunctional Nanocomposites for Laser Desorption Ionization Process.

A novel and facile strategy in developing a water stable magnetic metal-organic framework nanocomposite (Fe3 O4 @MOF) is herein reported, in which a Keggin polyoxometalate, phosphotungstic acid (HPW), was encapsulated within the MOF framework via one-pot synthesis method. The combination of HPW-embedded MOF and Fe3 O4 endowed the composite with high surface area, strong UV absorption, good hydrophilicity, and enhanced water stability. With these unique properties, the Fe3 O4 @MOF embedded HPW served as adsorbent as well as matrix for SALDI-MS (surface-assisted laser desorption ionization mass spectrometry) analysis of polar and non-polar compounds. The synergistic effect of Fe3 O4 and MOF showed an interference-free background at low mass region than the pristine MOF or Fe3 O4 counterparts. This simple approach can be used as new platform in developing magnetic MOF composites without the time consuming and labor-intensive preparation.