Magnetic Carbon Nanocomposite Research Articles

Removal of Ochratoxin A from water by novel adsorbent; magnetic carbon nanocomposites prepared from sugar beet wastes

Removal of Ochratoxin A from water by novel adsorbent; magnetic carbon nanocomposites prepared from sugar beet wastes

Magnetic carbon nanocomposites as a MALDI co-matrix enhancing MS-based glycomics.

More than 50% of all known proteins are glycosylated, which is critical for many biological processes such as protein folding and signal transduction. Glycosylation has proven to be associated with different mammalian diseases such as breast and liver cancers. Therefore, characterization of glycans is highly important to facilitate a better understanding of the development and progression of many human diseases. Although matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) offers several advantages such as ease of operation and short analysis times, however, due to the complexity of glycan structures and their low ionization efficiency, there are still challenges that need to be addressed to achieve sensitive glycan analysis. Here, magnetic carbon nanocomposites (CNPs@Fe3O4 NCs) were used as a new MALDI matrix or co-matrix for the analysis of glycans derived from different model glycoproteins and human blood serum samples. The addition of CNPs@Fe3O4 NCs to the matrix significantly enhanced glycan signal intensity by several orders of magnitude, and effectively controlled/reduced/eliminated in-source decay (ISD) fragmentation. The latter was attained by modulating CNPs@Fe3O4 NCs concentrations and allowed the simultaneous study of intact and fragmented glycans, and pseudo-MS3 analysis. Moreover, CNPs@Fe3O4 NCs was also effectively employed to desalt samples directly on MALDI plate, thus enabling direct MALDI-MS analysis of unpurified permethylated glycans derived from both model glycoproteins and biological samples. On-plate desalting enhanced sensitivity by reducing sample loss. Graphical abstract ᅟ.

Degradation of Acid Orange 7 by peroxymonosulfate activated with the recyclable nanocomposites of g-C3N4 modified magnetic carbon

Carbon-based catalysts have attracted high attention since they are greener and cheaper, while magnetic nanomaterials are very useful in environmental application because of the easy recovery and operation given by the magnetic separability. Therefore, graphitic carbon nitride modified magnetic carbon nanocomposites Fe3O4@C/g-C3N4 was prepared herein for the first time as a new carbon-based catalyst for the activation of peroxymonosulfate (PMS). The catalytic properties of Fe3O4@C/g-C3N4 in activating PMS for the degradation of Acid Orange 7 (AO 7), a model organic pollutant, were investigated. AO 7 degradation efficiency was significantly enhanced after modification of Fe3O4@C with g-C3N4, and the composite Fe3O4@C/g-C3N4 from loading of 5 wt% g-C3N4 and calcined at 300 °C for 30 min exhibited the best performance. AO 7 could be efficiently decolorized using the “Fe3O4@C/C3N4 (5%) + PSM” system within the pH range of 2–6, and 97% of AO 7 could be removed in 20 min without pH adjustment (pH = 4). Radical quenching and EPR studies confirmed that both sulfate and hydroxyl radicals produced from PMS activation were the active species responsible for the oxidation of AO 7. The degradation mechanism was suggested based on the experimental results and XPS analyses. It was proposed that the CO groups on the carbon surface of Fe3O4@C rather than the CO in g-C3N4 played a key role as the active sites for PMS activation. The catalyst was magnetically separable and displayed good stability and reusability, thus providing a potentially green catalyst for sustainable remediation of organic pollutants.

Synthesis of magnetic carbon nanocomposites by hydrothermal carbonization and pyrolysis

The fabrication of magnetic carbon nanostructures is emerging to develop composites with unique properties. Consolidating magnetic nanoparticles with carbon materials can be used in nanoelectronics, catalysis, optical application, biosensors, environmental remediation, energy, hydrogen storage, drug transport, magnetic resonance imaging and cancer diagnosis. In addition, thermochemical methods such as hydrothermal carbonization and pyrolysis are low energy processes that offer an efficient synthesis of the controlled morphology of magnetic carbon nanocomposite. These methods provide chemical and morphological improvements of the structure, such as high surface area, ordered nanosizes, crystal matrix, material stability, electrical conductivity, magnetic saturation and coercivity. This paper reviews the fabrication and properties of magnetic carbon nanocomposites.

A Highly Sensitive Dispersive Microextraction Method with Magnetic Carbon Nanocomposites Coupled with Dispersive Liquid–Liquid Microextraction and Two Miscible Stripping Solvents Followed by GC–MS for Quantification of 16 PAHs in Environmental Samples

In this work, a highly sensitive solid-phase-dispersive microextraction method was designed based on magnetic carbon nanocomposites as a magnetic solid-phase extraction sorbent coupled with dispersive liquid–liquid microextraction and two miscible stripping solvents (MSPE–DLLME) followed by gas chromatography–mass spectrometry (GC–MS) for determination of 16 polycyclic aromatic hydrocarbons (PAHs). By adopting this research methodology, a mixture of two miscible organic solvents is used not only as stripping solvent for MSPE, but also as extraction and disperser solvents for DLLME procedure. Several parameters such as amount of extraction adsorbent, type of stripping, extraction solvents and their volumes, salt effect, and pH and volume of sample solution were optimized to obtain high extraction recoveries. Finally, 2 µL of extraction phase was injected into GC–MS. Under optimal conditions, the method attained satisfactory precisions (RSD% ≤ 8.66), excellent limits of detection in the range of 0.1–0.5 ng kg−1 at S/N = 3, and very high enrichment factors in the range of 28,187–33,149 for 500 mL sample solution of different PAHs. The calibration curves of 16 extracted PAHs were linear in the range of 0.4–10,000 ng kg−1, with coefficients of determination (r2) between 0.9989 and 0.9999. The optimized method to determine 16 PAHs has been successfully applied in the real environment including waters, waste water, sewage, and soil.

Synthesis and characterization of graphitic magnetic mesoporous nanocomposite and its application in dye adsorption

A simple synthesis route has been developed to prepare pitch resin, which has been as carbon precursor to fabricate graphitic mesoporous carbon by a nanocasting process, and directly incorporating iron metal nitrates species as the magnetic particle precursors infiltrated into the mesoporous framework via two different approaches. The results of nitrogen adsorption-desorption showed a decrease in specific surface area and total volume with magnetic treatment. Comparison between the AB1 dye elimination with two magnetic nanocomposites was investigated. Experimental results showed that the adsorption capacities of the graphitic mesoporous carbons under the impregnation treatment (GMC-I) and the thermal treatment (GMC-II) modification nanoparticles for AB 1 dye were calculated to be 361.7 mg g−1 and 304.5 mg g−1, respectively. The results exhibited that the obtained magnetic mesoporous graphitic carbon nanocomposites can be used as efficient and recycled adsorbents for the removal of bulky dyes from any real sample. In additions, the data of kinetic was well fitted by pseudo second-order model, and the equilibrium adsorption isotherm data of dye onto the two magnetic GMC fitted by Langmuir isotherm model. The calculated thermodynamic parameters (ΔG, ΔH and ΔS) showed that the AB 1 dye adsorption onto the two nanocomposites was feasible, spontaneous and endothermic.

Chitosan-coated-magnetite with Covalently Grafted Polystyrene Based Carbon Nanocomposites for Hexavalent Chromium Adsorption

A chitosan-coated-magnetite with covalently grafted polystyrene (g-PS) based magnetic carbon nanocomposites composed of carbon coated magnetite nanoparticles with carbonized g-PS microsphere are prepared for effective hexavalent chromium (Cr(VI)) adsorption.

Magnetic cobaltic nanoparticle-anchored carbon nanocomposite derived from cobalt-dipicolinic acid coordination polymer: An enhanced catalyst for environmental oxidative and reductive reactions

Direct carbonization of cobalt complexes represents as a convenient approach to prepare magnetic carbon/cobalt nanocomposites (MCCNs) as heterogeneous environmental catalysts. However, most of MCCNs derived from consist of sheet-like carbon matrices with very sparse cobaltic nanoparticles (NPs), making them exhibit relatively low catalytic activities, porosity and magnetism. In this study, dipicolinic acid (DPA) is selected to prepare a 3-dimensional cobalt coordination polymer (CoDPA). MCCN derived from CoDPA can consist of a porous carbon matrix embedded with highly-dense Co0 and Co3O4 NPs. This magnetic Co0/Co3O4 NP-anchored carbon composite (MCNC) appears as a promising heterogeneous catalyst for oxidative and reductive environmental catalytic reactions. As peroxymonosulfate (PMS) activation is selected as a model catalytic oxidative reaction, MCNC exhibits a much higher catalytic activity than Co3O4, a benchmark catalyst for PMS activation. The reductive catalytic activity of MCNC is demonstrated through 4-nitrophenol (4-NP) reduction in the presence of NaBH4. MCNC could rapidly react with NaBH4 to generate H2 for hydrogenation of 4-NP to 4-aminophenol (4-AP). In comparison with other precious metallic catalysts, MCNC also shows a relatively high catalytic activity. These results indicate that MCNC is a conveniently prepared and highly effective and stable carbon-supported cobaltic heterogeneous catalyst for versatile environmental catalytic applications.

In vivo amelioration of aflatoxin B1 in broiler chicks by magnetic carbon nanocomposite

In vivo amelioration of aflatoxin B1 in broiler chicks by magnetic carbon nanocomposite

Coordination polymer-derived cobalt nanoparticle-embedded carbon nanocomposite as a magnetic multi-functional catalyst for energy generation and biomass conversion

Carbonization of cobalt complexes is a simple but versatile technique to prepare magnetic cobalt/carbon nanocomposites (MCoCNs) as heterogeneous catalysts for solution-based reactions. However, most of MCoCNs consist of sheet-like carbon matrices with sparse cobalt nanoparticles (Co NPs), making them exhibit low catalytic activities, porosity and magnetism. In this study, 2,6-Pyridinedicarboxylic acid (PDA) is selected to prepare a 3-D cobalt coordination polymer (CoPDA). MCoCN derived from CoPDA consists of a porous carbon matrix embedded with highly-dense Co NPs. This magnetic Co NP-embedded carbon nanocomposite (MCo@C) appears as a promising catalyst for energy generation and biomass conversion. As H2 generation from NaBH4 is selected as a model reaction for energy generation, MCo@C rapidly catalyzes hydrolysis of NaBH4 to generate H2. Ea obtained by MCo@C is also much lower than many noble metallic and cobalt-based catalysts. MCo@C also exhibits a stable and efficient catalytic activity for catalyzing hydrolysis of NaBH4 for multiple-cycle H2 production. In addition, MCo@C can be also used to catalyze conversion of the lignin model compound, vanillyl alcohol (VAL), to vanillin (VN) using H2O2 and air as oxidants. The selectivities for VN can be up to 99% and 100% using H2O2 and air as oxidants, respectively. MCo@C can be also re-used to catalyze VAL conversion to VN without significant loss of catalytic activity. These results indicate that MCo@C is a conveniently prepared and highly effective and stable magnetic cobalt/carbon nanocomposite for versatile catalytic applications. The preparation scheme here can be also applied to fabricate other carbon-supported metallic catalysts.

Application of magnetic carbon nanocomposites to remove melanoidin from aqueous media: kinetic and isotherm studies

This study examined the removal of melanoidin as a by-product of bioethanol production from aqueous solutions through an adsorption process using a magnetic carbon nanocomposite (MCNC). The magnetic adsorbent was synthesized by the chemical precipitation method and characterized by TEM, BET, and FTIR analysis. The effect of operational factors such as pH, adsorbent dosage, and temperature on the removal efficiency was modeled and optimized by the statistical response surface method. The data were well fitted by a second order polynomial model with R2 of 0.977. Based on the model, the process optimum conditions were introduced as adsorbent dosage of 413.6 ppm, pH = 3.03, and temperature of 39.9 °C that for these conditions the software predicted 90% removal efficiency for 40 ppm of melanoidin. Also, the data obtained from adsorption of melanoidin on the MCNC were fitted by a Langmuir isotherm model and a pseudo-second-order kinetic model. Finally, removal of melanoidin from a real alcohol industries wastewater was assessed such that 80.76% efficiency was obtained in the optimum condition after 30 min of the process.

Heterogeneous Fenton-like catalysis of Fe-MOF derived magnetic carbon nanocomposites for degradation of 4-nitrophenol

Magnetic Fe–Cx as heterogeneous Fenton-like catalysts were synthesized by the pyrolysis of Fe-MOF, and the catalytic activity of Fe–Cx for removal of 4-NP was significantly affected by pyrolysis temperature.

Magnetic porous carbon nanocomposites derived from metal-organic frameworks as a sensing platform for DNA fluorescent detection

Metal-organic frameworks (MOFs) have emerged as very fascinating functional materials due to their tunable nature and diverse applications. In this work, we prepared a magnetic porous carbon (MPC) nanocomposite by employing iron-containing MOFs (MIL-88A) as precursors through a one-pot thermolysis method. It was found that the MPC can absorb selectively single-stranded DNA (ssDNA) probe to form MPC/ssDNA complex and subsequently quench the labelled fluorescent dye of the ssDNA probe, which is resulted from the synergetic effect of magnetic nanoparticles and carbon matrix. Upon the addition of complementary target DNA, however, the absorbed ssDNA probe could be released from MPC surface by forming double-stranded DNA with target DNA, and accompanied by the recovery of the fluorescence of ssDNA probe. Based on these findings, a sensing platform with low background signal for DNA fluorescent detection was developed. The proposed sensing platform exhibits high sensitivity with detection limit of 1 nM and excellent selectivity to specific target DNA, even single-base mismatched nucleotide can be distinguished. We envision that the presented study would provide a new perspective on the potential applications of MOF-derived nanocomposites in biomedical fields.

Fabrication of a novel magnetic carbon nanocomposite adsorbent via pyrolysis of sugar

A new-fashioned fabrication recipe for a magnetic carbon nanocomposite (Fe3O4@C) via pyrolysis of sugar with magnetite (Fe3O4) nanoparticles was developed for the practical environmental application as an adsorbent. In order to synthesize Fe3O4@C, the thermal degradation of sugar was firstly investigated via thermo-gravimetric analysis (TGA) to explore the optimal pyrolytic conditions for fabricating Fe3O4@C. This study laid a great emphasis on the physicochemical characterization of pyrogenic Fe3O4@C through various analytical techniques, which experimentally validated that Fe3O4@C retained thin graphitic carbon layers containing carboxyl groups on the surface with the point of zero charge (pHpzc) of 7.5. Based on adsorption tests of methylene blue (MB), it was found the optimal mass ratio of sugar to Fe3O4 was 0.15 with pyrolysis temperature of 500 °C. The adsorption capacity of Fe3O4@C for MB was 52.6 mg g−1 and MB adsorption showed a strong pH dependence, which implies an active role of electrostatic interactions in the adsorption process. In regeneration experiments, Fe3O4@C retained 84% of its initial adsorption capacity after completing four consecutive adsorption cycles.

One-Step Fabrication of Magnetic Carbon Nanocomposite as Adsorbent for Removal of Methylene Blue

Magnetic Fe3O4@C nanocomposites with well-defined core@shell structure were synthesized via a facile one-step solvothermal process using ferrocene as both iron and carbon resource in the presence of hydrogen peroxide (H2O2). The as-prepared Fe3O4@C nanocomposites were employed as adsorbent materials for removal of methylene blue (MB) from aqueous solution. Several experimental parameters, including contact time, acidity of the solution, and initial MB concentration were investigated. The result showed that the equilibrium uptake of MB was related to the MB initial concentration as well as acidity of the solution. The adsorption kinetics of MB was dominated by the pseudo-second order reaction model. Significantly, the synthesized Fe3O4@C nanocomposites could be easily isolated from the adsorption system after adsorbing MB and showed prominent reusability. All results indicated that the prepared Fe3O4@C composites had the potential to be used as adsorbents for the removal of dye pollutant from wastewater.

Reproducible magnetic carbon nanocomposites derived from polystyrene with superior tetrabromobisphenol A adsorption performance

Easily reproducible magnetic carbon nanoadsorbents derived from plastic polystyrene (PS) by direct calcination of functionalized PS with an iron salt for effective TBBPA adsorption.

Adsorption of 1,1-dimethylhydrazine (UDMH) from aqueous solution using magnetic carbon nanocomposite: kinetic and thermodynamic study

In this work, removal of UDMH as a pollutant with considerable toxicity is studied using activated carbon magnetic nanocomposite with fast and easy separation. To optimize the process, effective parameters, such as pH, adsorbent dosage, contact time, and temperature, have been investigated. More than 90% UDMH removal efficiency obtained within 30 min of contact time, 20 mg of adsorbent at pH 6 and room temperature. The adsorption behavior was evaluated based on equilibrium data, using both the Langmuir and Freundlich isotherm models. It was found that adsorption data were interpreted by Freundlich model better than Langmuir model with regression coefficient of 0.9971. Besides, the adsorption data were well described by the pseudo-second-order kinetic model. The adsorption thermodynamic parameters showed that the adsorption process is endothermic and spontaneous with positive standard enthalpy of 2.74 J mol−1 and negative standard free energy of 29.08 kJ mol−1, respectively. Also standard entropy changes of 97.56 J mol−1 k−1 was calculated.

Aflatoxin B1 detoxification by magnetic carbon nanostructures prepared from maize straw

Magnetic carbon nanocomposites were prepared from maize wastes and were characterized by surface area analyzer, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric/differential thermal analysis (TG/DTA), and electron dispersive X-ray (EDX). The presence of iron oxide on the adsorbent surface was confirmed from SEM, XRD, and FT-IR analysis. Freundlich and Langmuir isotherms were used for the determination of adsorption parameters. The effect of pH on adsorption process was evaluated, and a decline in percent adsorption was noted at high pH. The equilibrium time at pH 7 and 3 was 96 and 180 min, respectively, and nearly 90% removal of aflatoxin B1 was achieved for both adsorbent. Pseudo-first-order and pseudo-second-order kinetic equations were used to analyze the kinetic data. Best fit was obtained with pseudo-first-order kinetics equation. The thermodynamics parameters were also determined, ΔS° was positive (64.438 kJ mol−1 deg−1) while ΔH° (−16.24 kJ mol−1) and ΔG° were negative (−1.949, −2.593, −3.238, and –3.882 kJ mol−1 corresponding to 30, 40, 50, and 60°C, respectively).

A label-free amperometric immunosensor for the detection of carcinoembryonic antigen based on novel magnetic carbon and gold nanocomposites

In this work, a novel label-free electrochemical immunosensor was developed for the quantitative detection of carcinoembryonic antigen (CEA).

Cr(vi) removal by magnetic carbon nanocomposites derived from cellulose at different carbonization temperatures

The carbon layer and iron of magnetic carbons play an important role in Cr(vi) removal from solutions with an initial pH of 7 and 2.