Carbon Magnetic Nanoparticles Research Articles

Selective adsorption of zearalenone by a novel magnetic molecularly imprinted carbon nanomaterial.

In this paper, the objective is to immobilize molecularly imprinted polymers (MIPs) onto the surface of magnetic carbon nanoparticles (Fe3O4@SiO2@C) to develop an effective method for the adsorption of zearalenone (ZEN). The prepared products were characterized by FT-IR, SEM, TEM, XRD, VSM, TGA, and BET. The content of zearalenone in corn samples was monitored by HPLC. The results indicate that the particle size of magnetic molecularly imprinted polymers (MMIPs) is approximately 200nm. The adsorption mechanism of MMIPs was confirmed by static adsorption and dynamic adsorption experiments. The maximum adsorption capacity was 1.56mg/g, and the adsorption equilibrium was reached within 50min. The scatchard model showed that MMIPs had two binding sites, a high-affinity binding site and a low-affinity site. Kinetic second-order fitting indicates that MMIPs are mainly through chemisorption. In the actual sample application, the limit of detection (LOD) and limit of quantitation (LOQ) were 0.3mg/L and 0.9mg/L, respectively. The recovery of corn with the standard addition of ZEN was 73.6-88.1%, and the relative standard deviation (RSD) was 2.86-5.63%. The results demonstrated that MMIPs possess the advantages of straightforward operation, high precision, and cost-effectiveness, rendering them suitable for rapid ZEN detection.

N-S co-doping lignin-based carbon magnetic nanoparticles as high performance supercapacitor and electromagnetic wave absorber

Recently, multifunctional lignin-based materials are gaining more and more attention due to their great potential for low-cost and sustainability. In this work, to obtain both an excellent supercapacitor electrode and an outstanding electromagnetic wave (EMW) absorber, a series of multifunctional nitrogen-sulphur (N-S) co-doped lignin-based carbon magnetic nanoparticles (LCMNPs) had been successfully prepared through Mannich reaction at different carbonization temperature. As compared with the directly carbonized lignin carbon (LC), LCMNPs had more nano-size structure and higher specific surface area. Meanwhile, with the increase of carbonization temperature, the graphitization of the LCMNPs could also be effectively improved. Therefore, LCMNPs-800 displayed the best performance advantages. For the electric double layer capacitor (EDLC), the optimal specific capacitance of LCMNPs-800 reached 154.2 F/g, and the capacitance retention after 5000 cycles was as high as 98.14 %. When the power density was 2204.76 W/kg, the energy density achieved 33.81 Wh/kg. In addition, N-S co-doped LCMNPs also exhibited strong electromagnetic wave absorption (EMWA) ability, whose the minimum reflection loss (RL) value of LCMNPs-800 was realized −46.61 dB at 6.01 GHz with an thickness of 4.0 mm, and the effective absorption bandwidth (EAB) was up to 2.11 GHz ranging from 5.10 to 7.21 GHz, which could cover the C-band. Overall, this green and sustainable approach is a promising strategy for the preparation of high-performance multifunctional lignin-based materials.

Magnetic carbon nanoparticles derived from Co-based metal–organic frameworks for magnetic solid-phase extraction and determination of phenylurea herbicides

Magnetic carbon nanoparticles composed of Co, CoO and graphitic carbon (Co/CoO@C) were prepared by direct carbonization of Co-MOF without the need of extra carbon precursors and magnetic particles under N2 atmosphere. The Co/CoO@C prepared by self-sacrificial template method possess high mesoporous architecture, a large number of adsorption sites, good graphitization degree and strong magnetic response. The material was constructed as an adsorbent for magnetic solid-phase extraction of four phenylurea herbicides from water and rice samples prior to high-performance liquid chromatography analysis. A series of experimental parameters affecting the extraction efficiency were optimized. Under optimal conditions, the established method revealed extremely fast extraction times (10 s), low limits of detection (0.05 μg/L, S/N = 3), good linearity (0.1–100 μg/L) within the linear correlation coefficient range of 0.9990–0.9997 and good precision (RSD < 5.72 %). The results confirmed that the Co/CoO@C exhibited an excellent adsorption capability and could be a stable and effective adsorbent for preconcentrating trace levels of phenylurea herbicides from water and rice samples. Moreover, the excellent adsorption performance together with low-cost, facile synthesis method endowed the Co/CoO@C great application prospect in sample preparation.

Magnetic carbon nanoparticles derived from candle soot for SALDI MS analyses of drugs and heavy metals in latent fingermarks

For decades, the analysis of fingerprints (FP) has been used as the primary biometric mean of human identification. In parallel, the chemical analysis of latent fingermark (LFM) with particular reference to “touch chemistry”, offersadditional intelligence to forensic examination; as such,continuous improvements in the versatility and sensitivity of detection of the molecular make up of FM is of obvious importance. In this light, we propose a facile approach to synthesize magnetic carbon nanoparticles (MCNPs) from candle soot for extraction and detection of endogenous and exogenous FM components. Initially, endogenous components of FM including fatty acids (FAs), squalene andtriacylgycerols(TAGs), were successfully extracted and detected using the developed MCNPs and surface assisted laser desorption/ionization-mass spectrometry (SALDI-MS). Furthermore, the MCNPs enabled the detection of exogenous substances including antihistamine,β-blocker, antibiotic drugs and lead in contaminated FMs, whilst providing characteristic and unique fragmentation patterns for each drugs in the FM. The influence of environmental factors such as temperature on the stability of the exogenous substances in FM was investigated by exposing the contaminated FM to different temperatures over 24 h, the findings revealed thedrugs' instability at high temperatures and undergo different degrees of degradationwhereas lead was more resilient to thermal stress. The detection oftriprolidine, metoprolol and sulfamethoxazolefrom pharmaceutical tablets in FM was successfully achieved by gently touching the tablet powder. Thelimit of detection (LOD) values of the drugs in the tablet forms were 50, 200 and 750 ng mL−1for triprolidine, metoprolol and sulfamethoxazole, respectively and their recovery rates were91.17% fortriprolidine, 94.67% formetoprolol and 120.86% for sulfamethoxazole. Finally, to create a genuine casework scenario, contaminated FM was deposited on glass and metal surfaces then subjected to extraction usingMCNPs and magnet without compromising the FM impression. Substrate control experiments revealed that the glass surface exhibiting some background signal, however, they did not interfere with the analysis and satisfactory extraction efficiency of endogenous and exogenous components of the FM on both surfaces was obtained using the MCNPs. Overall, this study proves the capability of MCNPs as new SALDI-MS substrate for both extraction and detection of FM components gathering more information pertaining to the donor’s lifestyle.

Enhancing adsorption efficiencies of organic molecules through covalently bonded structures of magnetic carbon nanoparticles

This study introduces a facile method for synthesizing covalently bonded magnetic carbon nanoparticles (MCNs) in which carboxylic acid-functionalized activated carbon nanospheres (ACN-COOH) are connected with amine-terminated iron oxide nanoparticles (NPs) (Fe3O4-NH2) via a carbodiimide crosslinking reaction. The adsorption characteristics of the developed magnetic nanoparticles (ACN-Fe3O4) were investigated using a standard cationic dye (methylene blue, MB). Two additional MCNs (multi-core and core@shell structures) were also prepared, and their adsorption performances were extensively compared. The developed ACN-Fe3O4 material thoroughly utilizes the strengths of activated carbon and Fe3O4 themselves, exhibiting large specific surface areas (708.4 m2/g) and strong magnetic properties (40.3 emu/g), resulting in high adsorption capacity (349.5 mg/g) and recycling efficiency (76 % of adsorption performance after four cycles). In addition, a study of the mechanism reveals that pore-filling processes are dominant with minor contributions from electrostatic interactions, π–π interactions, and n–π interactions. The developed covalently bonded magnetic carbon nanoparticles (ACN-Fe3O4) can thus be considered as competent adsorbents with the potential to compensate for the drawbacks of contemporary MCNs, such as, low adsorption capacity, and weak magnetic properties.

Magnetic Carbon Nanoparticles Derived from Candle Soot for SALDI MS Analyses of Drugs and Heavy Metals in Latent Fingermarks

Magnetic Carbon Nanoparticles Derived from Candle Soot for SALDI MS Analyses of Drugs and Heavy Metals in Latent Fingermarks

Application of the Fe3O4@activated carbon magnetic nanoparticles for the adsorption of metronidazole from wastewater: optimization, kinetics, thermodynamics and equilibrium studies

Application of the Fe3O4@activated carbon magnetic nanoparticles for the adsorption of metronidazole from wastewater: optimization, kinetics, thermodynamics and equilibrium studies

Sulfonated magnetic carbon nanoparticles from eucalyptus oil as a green and sustainable catalyst for converting fructose to 5-HMF

Sulfonated magnetic carbon nanoparticles (SMCNs) were synthesized from eucalyptus oil via co-pyrolysis with ferrocene and sulfonation by H2SO4. Catalytic performance of SMCNs for conversion of fructose to 5-hydroxymethylfurfural was examined within a designated range of reaction temperature (120–180 °C) and time (30–240 min). 84% conversion of fructose and 51.6% yield of 5-hydroxymethylfurfural could be achieved with catalyst-to-fructose mass ratio of 0.167 at 180 °C and the reaction time of 30 min. The magnetic property of SMCNs also facilitated recovery and recycling of the spent catalyst. Additionally, more than 50% yield of 5-hydroxymethylfurfural could be achieved after three cycles.

Surface Modification of Magnetic Nanoparticles by Carbon-Coating Can Increase Its Biosafety: Evidences from Biochemical and Neurobehavioral Tests in Zebrafish.

Recently, magnetic nanoparticles (MNPs) have gained much attention in the field of biomedical engineering for therapeutic as well as diagnostic purposes. Carbon magnetic nanoparticles (C-MNPs) are a class of MNPs categorized as organic nanoparticles. C-MNPs have been under considerable interest in studying in various applications such as magnetic resonance imaging, photothermal therapy, and intracellular transportof drugs. Research work is still largely in progress for testing the efficacy of C-MNPs on the theranostics platform in cellular studies and animal models. In this study, we evaluated the neurobehavioral toxicity parameters on the adult zebrafish (Danio rerio) at either low (1 ppm) or high (10 ppm) concentration level of C-MNPs over a period of two weeks by waterborne exposure. The physical properties of the synthesized C-MNPs were characterized by transmission electron microscopy, Raman, and XRD spectrum characterization. Multiple behavior tests for the novel tank, mirror biting, predator avoidance, conspecific social interaction, shoaling, and analysis of biochemical markers were also conducted to elucidate the corresponding mechanism. Our data demonstrate the waterborne exposure of C-MNPs is less toxic than the uncoated MNPs since neither low nor high concentration C-MNPs elicit toxicity response in behavioral and biochemical tests in adult zebrafish. The approach combining biochemical and neurobehavioral approaches would be helpful for understanding C-MNPs association affecting the bioavailability, biosafety, interaction, and uptake of these C-MNPs in the living organism.

One-step fabrication of bifunctional self-assembled oligopeptides anchored magnetic carbon nanoparticles and their application in copper (II) ions removal from aqueous solutions

Copper ion (Cu (II)) pollution has attracted much attention due to its remarkable toxic domino effect at excess amount. Efficient Cu (II) ions removal is thus a prerequisite for wastewater recycling. Herein, we present a facile and environmentally benign strategy to fabricate thiol (SH)-functionalized Fe3O4@C nanoparticles (denoted as Fe3O4@C-SH NPs) based on one-step self-assembling of a bifunctional oligopeptide with a sequence of Cys-Lys-Cys-Lys-Cys-Lys (CK–VI) for highly efficient removal of copper ions (Cu (II)) in aqueous solutions. Under the physiological conditions, CK–VI readily self-organized into a robust and tailor-made functional monolayer predominately composed of well-packed β-sheets on the surface of Fe3O4@C NPs with their thiol groups standing on the outermost layer. The resulting Fe3O4@C-SH NPs containing abundant thiol active sites exhibited excellent adsorption capacity (up to 28.8 mg g−1) and selectivity for Cu (II) ions over coexisting ions. Compared with other covalent grafting methods with multistep processes and in harsh conditions, the proposed oligopeptides assembly-based coating method makes it possible to rapidly fabricate the Fe3O4@C-SH NPs in a simple mild one-step aqueous process with low cost. The current study provides facile and environmentally friendly approaches to rapidly tailor multifunctional surfaces of NPs for various toxic metal ions removal from wastewater.

Characterization of glycan isomers using magnetic carbon nanoparticles as a MALDI co-matrix.

Matrix-assisted laser desorption ionization-in source decay (MALDI-ISD) analysis is a useful technique in the structural analysis of glycans. Our recent publication demonstrated that magnetic carbon nanoparticles (MCNPs), used as a MALDI co-matrix, significantly enhanced ISD efficiency for glycomic analysis by MALDI-TOF. In this study, MCNPs were used for the structural study of isomeric glycans. Results from the standard glycans confirmed easy distinction of positional and linkage isomers without the need for further derivatization of glycan molecules. Extensive glycosidic and cross-ring fragmented ions provided different fragment patterns for various glycan isomers. Core- and branch-fucosylated isomers were distinguished by several unique ions, and pseudo-MS3 data were used to recognize the fucosylated branch. Although no diagnostic fragment ion was observed for 2,3- and 2,6-linked sialic acid isomers, their MALDI-ISD patterns were found to be significantly different (P < 0.05). Furthermore, the method introduced in this study could not only be used for the identification of glycan isomers but has also proved effective for the isomeric structural confirmation of gangliosides. GD1a and GD1b gangliosides were easily distinguished by the diagnostic ion originated from GD1a, produced by Z4αZ2β cleavages. Moreover, liquid chromatography coupled with MALDI-TOF was applied to analyze N-glycan isomers derived from a pooled human blood serum sample, providing an alternative method of isomeric glycomic analysis of biological specimens.

On-demand CO release for amplification of chemotherapy by MOF functionalized magnetic carbon nanoparticles with NIR irradiation

Carbon monoxide (CO) gas therapy combined with chemotherapy and photothermal therapy (PTT) is a promising treatment mode for malignant tumor. Herein, we firstly reported doxorubicin (DOX) loaded Mn carbonyl modified Fe (Ⅲ)-based nanoMOFs (MIL-100) coated PEGylated magnetic carbon nanoparticles (denoted as MCM@PEG-CO-DOX NPs) as theranostics nanoplatforms for near-infrared (NIR)-responded CO-DOX combination therapy. MIL-100 as a good nanocarrier of DOX with high loading capacity can also chelate the Mn carbonyl after a smart modification. Meanwhile, magnetic carbon core possessed photothermal effect, which can convert the NIR light to heat by an 808 nm laser irradiation, resulting in the on-demand release of CO and DOX. As a result, combining with PTT, MCM@PEG-CO-DOX NPs killed tumor efficiently. Moreover, our synthesized MCM@PEG-CO-DOX NPs were capable of realizing tumor dual-mode imaging including magnetic resonance imaging (MRI) and photoacoustic imaging (PAI).

Magnetic lignin-based carbon nanoparticles and the adsorption for removal of methyl orange

In order to expand the application of lignin, magnetic lignin-based carbon nanoparticles (MLBCN) were synthesized using a precipitation-carbonization process and the structure was confirmed by FTIR, XRD, Raman, BET, SEM, DLS and VSM. The adsorption of MLBCN for methyl orange was consistent with the Langmuir model and pseudo-second-order model, showing monolayer adsorption, with a maximum adsorption capacity of 113.0 mg/g and chemisorption being the rate-controlling step. This process was exothermic and of entropy reduction, showing spontaneous below 35 °C. MLBCN could be used under near neutral conditions and easily regenerated. This study demonstrates that MLBCN is promising as an efficient, sustainable absorbent.

Controlled synthesis of magnetic carbon nanoparticles via glycerol/ferrocene co-pyrolysis with magnetic induction

We performed a controlled synthesis of magnetic carbon nanoparticles (M-CNPs) via co-pyrolysis of glycerol and ferrocene with magnetic induction. The morphology of the synthesized M-CNPs was confirmed by transmission electron microscopy, and thermogravimetric analysis was used to analyze the carbon and Fe contents. M-CNPs that responded to magnetic stimulation were also examined with an AC-magnetic susceptibility analyzer. Our investigations on the influence of synthesis temperature in the range 700–1000°C suggested that for an initial glycerol to ferrocene weight ratio of 3:1 and a temperature of 800°C gave the highest yield of M-CNPs. Comparing the synthesis with and without magnetic induction, the controlled synthesis under the influence of magnetic induction shows promise as a method for producing high quality M-CNPs in high yields.

Synthesis of magnetic alloy-filling carbon nanoparticles in super-critical benzene irradiated with an ultraviolet laser.

Magnetic nanoparticles are of great importance particularly in the field of biomedicine as well as nanotechnology and nano materials science and technology. Here, we synthesise magnetic alloy-filling carbon nanoparticles (MA@C NPs) via the following two-step procedure; (1) Irradiation of a laser beam of 266 nm wavelength into super-critical benzene, in which both ferrocene and cobaltocene are dissolved, at 290 °C; and (2) annealing of the particles at 600 and 800 °C. We find that the core particles are composed of cobalt (Co), iron (Fe) and oxygen (O) and covered with carbon layers. The structure of the core particles as-synthesised, and annealed at 600 and 800 °C, is, respectively, amorphous, CoFe2O4 and FeCo. We also investigate the viability of L929 cells in the presence of MA@C NPs and find that there is no serious advert effect of the MA@C NPs on the cell viability thanks to the carbon layers covering the core particles. The magnetic properties are well characterised. The saturation and remnant magnetisation and coercivity increase and as a result, the hyperthermic efficiency becomes higher with an increase in the annealing temperature. The further modification of the surface of the present particles with several functional molecules becomes easier due to the carbon layers, which makes the present particles more valuable. It is therefore supposed that the presently synthesised MA@C NPs may well be utilised for nanotechnology-based biomedical engineering; e.g., nano bioimaging, nano hyperthermia and nano surgery.

Nitrate adsorption by synthetic activated carbon magnetic nanoparticles: kinetics, isotherms and thermodynamic studies

AbstractIn this study, synthesized Fe3O4 magnetic nanoparticle (MNP) coated on powder activated carbon was applied for the adsorption of nitrate from aqueous solutions. This novel adsorbent was then characterized by Scanning electron microscopy, Transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscope, and N2 adsorption–desorption. Effects of variables such as pH, contact time, initial nitrate concentration, adsorbent concentration, and co-existing anions were all evaluated in detail. The adsorption of nitrate fitted best with the Langmuir isotherm (R2 = 0.993) and pseudo-second-order kinetic models (R2 = 0.998). The equilibrium time and the maximum monolayer capacity (Qo) were determined to be 60 min and 57.1 mg/g, respectively (at pH 3). Thermodynamic studies revealed that the adsorption process of nitrate was spontaneous and endothermic. Moreover, the adsorption of nitrate followed the circumstantial interface in solid/liquid phases. Eventually, the activated carbon-...

Enhanced magnetorheological performance of highly uniform magnetic carbon nanoparticles.

Magnetic carbon nanoparticles (MC NPs) are prepared on a multi-gram scale through carbonization of iron-doped polypyrrole nanoparticles (PPy NPs). Three different-sized MC NPs (ca. 40, 60 and 90 nm) are prepared and adopted as dispersing materials for magnetorheological (MR) fluids to investigate the influence of particle size on MR properties. The MC NP-based MR fluids exhibit outstanding MR performances compared to the conventional magnetic carbon material-based fluids. In addition, the MR activities are enhanced with decreasing particle diameter and increasing applied magnetic field strength. Furthermore, anti-sedimentation properties are examined in order to achieve in-depth insight into the effect of the particle size on MR fluids.

Chemiluminescence assay for the glycoprotein tenascin-C based on aptamer-modified carboxylated magnetic carbon nanoparticles

We report on a method for chemiluminescence (CL) determination of the glycoprotein tenascin-C. Carboxylated carbon nanoparticles (cCNPs) were prepared from activated carbon. Next, the cCNPs were conjugated to magnetic beads (MBs) with a diameter of ~1 μm by linking its carboxy groups to the amino groups of the MBs. The assay involves the following steps: (a) An aptamer labeled with the CL reagent N-(4-aminobutyl)-N-ethylisoluminol (ABEI) (the labeled aptamer) was adsorbed onto the surface of the carboxy-modified magnetic carbon nanoparticles to form labeled aptamer modified cCNPs-MBs. (b) On addition of sample tenascin-C, it will interact with the labeled aptamer to form a complex with the labeled aptamer. (c) This tenascin-aptamer complex is then dissociated from the surface of the particles and detected by CL whose intensity is linearly related to the concentration of tenascin-C in the 1 pM to 1 nM range. The detection limit is as low as 0.4 pM, and the RSD is 4.2 % at a 50 pM level (for n = 7). The method has been successfully applied to the determination of tenascin-C in human serum samples and holds promise as a widely applicable general platform for aptamer-based CL detection of proteins. A novel method for Glycoprotein tenascin-C detection based on interaction between carboxylic carbon nanoparticles and aptamer is developed.

Crystalline magnetic carbon nanoparticle assisted photothermal delivery into cells using CW near-infrared laser beam.

Efficient and targeted delivery of impermeable exogenous material such as small molecules, proteins, and plasmids into cells in culture as well as in vivo is of great importance for drug, vaccine and gene delivery for different therapeutic strategies. Though advent of optoporation by ultrafast laser microbeam has allowed spatial targeting in cells, the requirement of high peak power to create holes on the cell membrane is not practical and also challenging in vivo. Here, we report development and use of uniquely non-reactive crystalline magnetic carbon nanoparticles (CMCNPs) for photothermal delivery (PTD) of impermeable dyes and plasmids encoding light-sensitive proteins into cells using low power continuous wave near-infrared (NIR) laser beam. Further, we utilized the magnetic nature of these CMCNPs to localize them in desired region by external magnetic field, thus minimizing the required number of nanoparticles. We discovered that irradiation of the CMCNPs near the desired cell(s) with NIR laser beam leads to temperature rise that not only stretch the cell-membrane to ease delivery, it also creates fluid flow to allow mobilization of exogenous substances to the delivery. Due to significant absorption properties of the CMCNPs in the NIR therapeutic window, PTD under in vivo condition is highly possible.

Synthesis and properties of Fe3O4-activated carbon magnetic nanoparticles for removal of aniline from aqueous solution: equilibrium, kinetic and thermodynamic studies

In this study, powder activated carbon (PAC) and magnetic nanoparticles of iron (III) oxide were used for synthesis of Fe3O4-activated carbon magnetic nanoparticles (AC-Fe3O4 MNPs) as an adsorbent for the removal of aniline. The characteristics of adsorbent were evaluated by SEM, TEM, XRD and BET. Also, the impact of different parameters such as pH, contact time, adsorbent dosage, aniline initials concentration and solution temperature were studied. The experimental data investigated by Langmuir and Freundlich adsorption isotherms and two models kinetically of pseudo first-order and pseudo second-order. The results indicated that the adsorption followed Langmuir and pseudo second-order models with correlation r2 > 0.98 and r2 > 0.99, respectively. The equilibrium time was obtained after 5 h. According to Langmuir model, the maximum adsorption capacity was 90.91 mg/g at pH = 6, and 20°C. The thermodynamic parameters indicated that adsorption of aniline on magnetic activated carbon was exothermic and spontaneous. This synthesized AC-Fe3O4 MNPs due to have advantages such as easy and rapid separation from solution could be applied as an adsorbent effective for removal of pollutants such as aniline from water and wastewater.