Magnetic Composite Nanoparticles Research Articles

Polymer-Magnetic Composite Particles of Fe₃O₄/Poly(o-anisidine) and Their Suspension Characteristics under Applied Magnetic Fields.

Fe3O4/poly(o-anisidine) (POA) magnetic composite nanoparticles with their core-shell structure were synthesized by chemical oxidation polymerization technique and adopted as a magneto-responsive magnetorheological (MR) material. The chemical structure and morphology of core-shell nanoparticles were identified by FT-IR, SEM, TEM, and elemental analyzer. Pycnometer and vibrating sample magnetometer showed that the magnetic saturation and density of the Fe3O4/POA particles were reduced by the POA shell coatings. The rheological properties of the MR suspension dispersed in a silicone oil at various magnetic field strengths were investigated using a rotating rheometer under a magnetic field. The resulting MR suspension showed a typical Newtonian fluid behavior in the absence of external stimuli. When an external magnetic field was applied, it formed a strong chain structure, acting like a solid with a yield stress. Further solid-like behaviors were observed from storage shear relaxation and viscoelastic tests. Finally, the Fe3O4/POA nanoparticles showed better dispersion stability than pure Fe3O4 nanoparticles with 50% improvement.

Magnetic SERS Composite Nanoparticles for Microfluidic Oil Reservoir Tracer Detection and Nanoprobe Applications

Composite magnetic nanoparticles are designed and synthesized with different morphologies as surface-enhanced Raman scattering (SERS) substrates or SERS-active particles. Through the incorporation of a magnetic functionality, we provide a means to concentrate SERS-active nanoparticles in a low-volume microfluidic channel where the detected entity is now either a flowing analyte (e.g., tracer or chemical) or SERS-active particles contained in a target reservoir fluid. This collection strategy allows for detection using small amounts of material and can be optimized to provide selectivity for trace-level materials detection at the wellsite. We also demonstrate low-concentration detection of dye molecules used for reservoir tracer materials by optimizing the fluid flow rate and the intensity of the magnetic field. Thus, we developed an efficient magnetic SERS microfluidic detection platform for in situ monitoring trace level of analyte molecules. The integration of SERS with microfluidic systems also can extend the application of Raman detection in biomedical research and microreactor monitoring where low volumes of expensive samples make traditional detection methods ineffective or cost prohibitive.

Multifunctional magnetic ZnFe2O4-hydroxyapatite nanocomposite particles for local anti-cancer drug delivery and bacterial infection inhibition: An in vitro study

Abstract In this study, a co-precipitation method was applied to synthesize the ZnFe2O4 and ZnFe2O4 Hydrxoapatite (HAp) nanostructures. The microstructure and morphological characteristics of the nanoparticles were studied and well discussed. A dose-dependent biological evaluation comprising of their minimum inhibitory concentration (MIC) antibacterial features as well as their magnetic characteristics were analyzed. The results of vibrating-sample magnetometer (VSM) showed nanoscaled ZnFe2O4 HAp had lower saturation magnetization as well as higher coercive field than ZnFe2O4, which enables the ZnFe2O4 HAp nanoparticles to stimulate cell proliferation, differentiation and adhesion. A remarkable inhibitory effect of the nanoscaled ZnFe2O4 HAp was recognized on bacterial proliferation and growth in the optimal dose, 0.078 mg/L. Besides, a dose-dependent cytocompatibility tests of the nanoparticles on the HEK normal cell and G292 cancer cell was assessed by 3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide assay (MTT). All nanoparticles were cytocompatible and no cytotoxicity effect on normal and cancer cells was observed in the dose-dependent test. In addition, an in vitro test of the drug release from drug-loaded ZnFe2O4-HAp nanocarrier were investigated and well described. The Inhibitory effect of the drug-loaded ZnFe2O4-HAp nanoparticles was investigated in-vitro so that the nanoparticle possessed the ability for inhibiting cancer cell proliferation and growth. By the increment of the nanoparticles concentrations, G292 cancer cell proliferation was inhibited, while, HEK normal cell proliferation was stimulated. Conclusively for the first time, a robust composite based nanostructure as a promising material was developed for multiple applications of bone filler, drug delivery and cancer treatment.

Removal characteristics of chromium by activated carbon/CoFe2O4 magnetic composite and Phoenix dactylifera stone carbon

Activated carbon (AC) was synthesized from Phoenix dactylifera stones and then modified by CoFe2O4 magnetic nanocomposite for use as a Cr(VI) adsorbent. Both AC/CoFe2O4 composite and AC were fully characterized by FTIR, SEM, XRD, TEM, TGA, and VSM techniques. Based on the surface analyses, the addition of CoFe2O4 nanoparticles had a significant effect on the thermal stability and crystalline structure of AC. Factors affecting chromium removal efficiency like pH, dosage, contact time, temperature, and initial Cr(VI) concentration were investigated. The best pH was found 2 and 3 for Cr adsorption by AC and AC/CoFe2O4 composite, respectively. The presence of ion sulfate had a greater effect on the chromium sorption efficiency than nitrate and chlorine ions. The results illustrated that both adsorbents can be used up to seven times to adsorb chromium. The adsorption process was examined by three isothermal models, and Freundlich was chosen as the best one. The experimental data were well fitted by pseudo-second-order kinetic model. The half-life (t1/2) of hexavalent chromium using AC and AC/CoFe2O4 magnetic composite was obtained as 5.18 min and 1.52 min, respectively. Cr(VI) adsorption by AC and AC/CoFe2O4 magnetic composite was spontaneous and exothermic. In general, our study showed that the composition of CoFe2O4 magnetic nanoparticles with AC can increase the adsorption capacity of AC from 36mg/L to 70mg/L.

Facile bulk preparation and structural characterization of agglomerated γ-Fe2O3/SiO2 nanocomposite particles for nucleic acids isolation and analysis

Two facile methods for bulk preparation of γ-Fe2O3/SiO2 agglomerated magnetic nanocomposite (MNC) particles for magnetic separation of nucleic acids (NAs) are compared together. Different silica coating approaches were used for iron oxide silanization: Stöber method and sodium silicate dense-liquid process. Additional thermal treatment at 750 °C provided thermal and structural stability to the MNCs. The structural characteristics, magnetic properties, size and morphology of the synthesized materials have been studied. To validate the synthesized materials, the MNCs were used for the isolation of nucleic acids from human buccal epithelium cells and two human biosamples (whole blood and plasma) with addition of pathogenic viruses. It was shown that the prepared near-micron sized agglomerates of superparamagnetic (Ms = 40–45 emu/g) γ-Fe2O3/SiO2 MNC particles are fully coated with silica. The synthesized materials combine the advantages of nanosized (superparamagnetism) and micron-sized objects (separability, average precipitation stability). Both types of the MNCs described in the paper have demonstrated similar effectiveness of NAs isolation, comparable with commercial MAGNO-sorb® total NAs isolation kit (InterLabService, Russia) used as a reference. The appropriate structural stability, high magnetization and proper purity of the isolated NAs (A260/A280 ratio near 1.9) make the studied MNCs promising materials for magnetic bioseparation.

Synergetic effect of Ni2+ and 5-acrylamidobenzoboroxole functional groups anchoring on magnetic nanoparticles for enhanced immobilization of horseradish peroxidase

In this work, a novel Ni2+&AABOB bifunctional core–shell magnetic composite nanoparticles (MNPs), Fe3O4@p(AABOB-co-AIM-Ni2+), were synthesized for the immobilization of horseradish peroxidase (HRP). Two kinds of interaction are simultaneously incorporated to improve the stability and reusability of immobilized HRP: one is the coordination between Ni2+ and amide group in HRP, and the other is the interaction of the wulff-type boronic acid group with cis-diol-containing HRP which belongs to a type of glycoproteins. Accordingly, the proposed approach achieved high enrichment capacity (174.75 mg/g, protein/beads), and the activity of immobilized HRP still achieved 80% after reuse for 5 cycles. The degradation efficiency of phenol in the presence of immobilized HRP reached 93% within 10 min, which was significantly higher than that of free HRP only about 50% within 20 min. In addition, the immobilized HRP can be easily separated from the reaction solution by an external magnetic field.

Fe3O4@Au composite magnetic nanoparticles modified with cetuximab for targeted magneto-photothermal therapy of glioma cells.

BackgroundThermoresponsive nanoparticles have become an attractive candidate for designing combined multimodal therapy strategies because of the onset of hyperthermia and their advantages in synergistic cancer treatment. In this paper, novel cetuximab (C225)-encapsulated core-shell Fe3O4@Au magnetic nanoparticles (Fe3O4@Au-C225 composite-targeted MNPs) were created and applied as a therapeutic nanocarrier to conduct targeted magneto-photothermal therapy against glioma cells.MethodsThe core-shell Fe3O4@Au magnetic nanoparticles (MNPs) were prepared, and then C225 was further absorbed to synthesize Fe3O4@Au-C225 composite-targeted MNPs. Their morphology, mean particle size, zeta potential, optical property, magnetic property and thermal dynamic profiles were characterized. After that, the glioma-destructive effect of magnetic fluid hyperthermia (MFH) combined with near-infrared (NIR) hyperthermia mediated by Fe3O4@Au-C225 composite-targeted MNPs was evaluated through in vitro and in vivo experiments.ResultsThe inhibitory and apoptotic rates of Fe3O4@Au-C225 composite-targeted MNPs-mediated combined hyperthermia (MFH+NIR) group were significantly higher than other groups in vitro and the marked upregulation of caspase-3, caspase-8, and caspase-9 expression indicated excellent antitumor effect by inducing intrinsic apoptosis. Furthermore, Fe3O4@Au-C225 composite-targeted MNPs-mediated combined hyperthermia (MFH+NIR) group exhibited significant tumor growth suppression compared with other groups in vivo.ConclusionOur studies illustrated that Fe3O4@Au-C225 composite-targeted MNPs have great potential as a promising nanoplatform for human glioma therapy and could be of great value in medical use in the future.

PH-Responsive Charge-Conversional and Hemolytic Activities of Magnetic Nanocomposite Particles for Cell-Targeted Hyperthermia.

Magnetic nanocomposite particle (MNP)-induced hyperthermia therapy has been restricted by inefficient cellular targeting. pH-responsive charge-conversional MNPs can enhance selective cellular uptake in acidic cells like tumors by sensing extracellular acidity based on their charge alteration. We have synthesized new, pH-induced charge-conversional, superparamagnetic, and single-cored Fe3O4 nanocomposite particles coated by N-itaconylated chitosan (NICS) cross-linked with ethylene glycol diglycidyl ether (EGDE) (Fe3O4-NICS-EGDE) using a simple, one-step chemical coprecipitation–coating process. The surface of the Fe3O4-NICS-EGDE nanocomposite particles was modified with ethanolamine (EA) via aza-Michael addition to enhance their buffering capacity, aqueous stability, and pH sensitivity. The designed Fe3O4-NICS-EGDE-EA nanocomposite particles showed pH-dependent charge-conversional properties, colloidal stability, and excellent hemocompatibility in physiological media. By contrast, the charge-conversional properties enabled microwave-induced hemolysis only under weakly acidic conditions. Therefore, the composite particles are highly feasible for magnetically induced and targeted cellular thermotherapeutic applications.

Ag nanoparticles decorated Fe3O4/chitosan nanocomposite: synthesis, characterization and application toward electrochemical sensing of hydrogen peroxide

We studied a rapid, sensitive and selective amperometric sensor for determination of hydrogen peroxide by electrodeposited Ag NPs on a modified glassy carbon electrode (GCE). The modified GCE was constructed through a step by step modification of magnetic chitosan functional composite (Fe3O4–CH) and high-dispersed silver nanoparticles on the surface. The resulted Ag@Fe3O4–CH was characterized by various analytical methods including Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy and cyclic voltammetry. The proposed sensor employed Ag@Fe3O4–CH/GCE as the working electrode with a linear current response to the hydrogen peroxide concentration in a wide range from 0.01 to 400 µM with a low limit of detection (LOD = 0.0038 µM, S/N = 3). The proposed sensor showed superior reproductivity, sensitivity and selectivity for the detection of hydrogen peroxide in environmental and clinical samples.

Merging Icosahedral Boron Clusters and Magnetic Nanoparticles: Aiming toward Multifunctional Nanohybrid Materials.

All-inorganic-made nanohybrid icosahedral boron cluster magnetic nanoparticles have been prepared. These magnetic nanoparticles (MNPs) consist of a magnetic core and an inorganic carboranylphosphinate shell. The phosphinate is directly bonded to the iron atoms of the surface in a bidentated coordination mode. The nanoparticles have been characterized by TEM, X-ray powder diffraction, infrared spectroscopy, energy dispersive X-ray analysis, high resolution X-ray photoelectron spectroscopy, magnetometry measurements, and redox titration, among other techniques. These studies have led to a composition (1-OPH(O)-1,7-closo-C2B10H11)8(2Fe3O4·Fe2O3)13 that implies a surface coverage of 61.3 ± 7.4% by the ligand. When these MNPs go through sterilization in one autoclave, the magnetic hysteresis studies suggest minimal change before and after sterilization; this could erroneously indicate that there have not been any changes in the MNP composition. However, the Fe2+ titration demonstrates that after sterilization only 1/7 of the Fe is Fe2+, leading to a core formula of Fe3O4·2Fe2O3 with a concomitant loss of ligand to a final ratio of 1:70 (carborane: Fe), and a final coverage by the ligand of 11.2 ± 1.4%. These studies bring relevant information on the behavior of the widely used MNPs and clearly show how the sterilization process needed for biological tests may alter the composition of the core and the loading of a peripheral ligand. In the particular case reported here, the liberated ligand has not been oxidized nor altered through the sterilization process.

Multistage Targeting Strategy Using Magnetic Composite Nanoparticles for Synergism of Photothermal Therapy and Chemotherapy.

Mitochondrial-targeting therapy is an emerging strategy for enhanced cancer treatment. In the present study, a multistage targeting strategy using doxorubicin-loaded magnetic composite nanoparticles is developed for enhanced efficacy of photothermal and chemical therapy. The nanoparticles with a core-shell-SS-shell architecture are composed of a core of Fe3 O4 colloidal nanocrystal clusters, an inner shell of polydopamine (PDA) functionalized with triphenylphosphonium (TPP), and an outer shell of methoxy poly(ethylene glycol) linked to the PDA by disulfide bonds. The magnetic core can increase the accumulation of nanoparticles at the tumor site for the first stage of tumor tissue targeting. After the nanoparticles enter the tumor cells, the second stage of mitochondrial targeting is realized as the mPEG shell is detached from the nanoparticles by redox responsiveness to expose the TPP. Using near-infrared light irradiation at the tumor site, a photothermal effect is generated from the PDA photosensitizer, leading to a dramatic decrease in mitochondrial membrane potential. Simultaneously, the loaded doxorubicin can rapidly enter the mitochondria and subsequently damage the mitochondrial DNA, resulting in cell apoptosis. Thus, the synergism of photothermal therapy and chemotherapy targeting the mitochondria significantly enhances the cancer treatment.

Preparation and characterization of magnetic γ-Al2O3 ceramic nanocomposite particles with variable Fe3O4 content and modification with epoxide functional polymer

Porous γ-alumina (γ-Al2O3) is one of widely used ceramic materials. To maximize the application potentials attempt was made to prepare multifunctional γ-Al2O3 ceramic composite particles following magnetization and then seeded polymerization with epoxide functional glycidyl methacrylate (GMA). γ-Al2O3 particles were first prepared by a modified sol-gel approach and then doped with variable content Fe3O4 nanoparticles. At higher Fe3O4 content the magnetite nanoparticles were oriented into needle like hairy structure basically grown from the surface of γ-Al2O3 particles. Before the seeded polymerization the magnetic γ-Al2O3 particles were modified with SiO2 layer to improve the compatibility with the PGMA layer. The produced multifunctional ceramic particles were named as γ-Al2O3/Fe3O4/SiO2/PGMA nanocomposite because one of the phases constituting Fe3O4 was in nano-size range. The produced nanocomposite particles possessed superparamagnetic properties and could be isolated from the dispersion medium by external magnetic field. Fourier Transform IR (FTIR) and X-ray photoelectron spectroscopic (XPS) data revealed that final nanocomposite particles contained reactive epoxide groups on or near the surface. The produced multifunctional γ-Al2O3 ceramic nanocomposite particles can be useful in biotechnology, catalysis and adsorbents for pollutant removal.

Preparation and Characterization of Fe3O4@SiO2@NMDP core-shell structure composite magnetic nanoparticles

Fe3O4@SiO2@nimodipine(NMDP) core-shell structure nanoparticles were prepared successfully by sonochemical method. The composite magnetic nanoparticles with SiO2 coating are effective and accurate for completing the delivery of NMDP in vitro. The samples are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR). Drug release was detected by high performance liquid chromatography (HPLC). The result shows the release rate of NMDP reach to 61.3% in a short time of 40min in the PBS, and to 100% in a time of 60min. The Fe3O4@SiO2@NMDP NPs prepared show a super-paramagnetic property with a saturation magnetization value of 21.4emu/g. The accordingly composite magnetic fluid with a saturation magnetization value of 14.8emu/g shows the spicules in external magnet field. It indicates that SiO2 coating plays an important role and has a great potential application in treatment of high blood pressure and cerebrovascular disease by using magnetic drug delivery technology.

Removal of arsenic from gold processing circuits by use of novel magnetic nanoparticles

ABSTRACTArsenic adversely affects gold mining operations by interfering with the extraction of gold, as well as posing a significant health and environmental hazard. While a number of technologies are available for removing arsenic, none of them is effective under all conditions. Although adsorption is a promising approach, most methods focus on the purification of water under neutral or acidic conditions and tend to be less effective in gold mining process waters, operating under highly alkaline conditions. In this study, the removal of As(III) and As(V) from both arsenic-only solutions and simulated process waters using composite magnetic nanoparticles was investigated. The nanoparticles consisted of magnetite (Fe3O4) or maghemite (γ-Fe2O3) cores covered by various metal oxides with Langmuir adsorption capacities of As(III) and As(V) ranging from 31.4 to 79.1 mg g−1 and 10.2 to 25.5 mg g−1, respectively, in arsenic-only solutions at pH 9. The adsorption capacities were further characterised by adsorption tests conducted in simulated process waters. The ability to remove As(III) is of particular importance as it is harder to remove it from alkaline solutions than As(V). The magnetic cores allow simple and efficient magnetic recovery of the As-loaded nanoparticles.

Melatonin potentiates "inside-out" nano-thermotherapy in human breast cancer cells: a potential cancer target multimodality treatment based on melatonin-loaded nanocomposite particles.

PurposeWith the wide recognition of oncostatic effect of melatonin, the current study proposes a potential breast cancer target multimodality treatment based on melatonin-loaded magnetic nanocomposite particles (Melatonin-MNPs).MethodsMelatonin-MNPs were fabricated by the single emulsion solvent extraction/evaporation method.ResultsBased on the facilitated transport of melatonin by the GLUT overexpressed on the cell membrane, such Melatonin-MNPs can be more favorably uptaken by MCF-7 cells compared with the melatonin-free nanocomposite particles, which indicates the cancer targeting ability of melatonin molecule. Inductive heating can be generated by exposure to the Melatonin-MNPs internalized within cancer cells under alternative magnetic field, so as to achieve the “inside-out” magnetic nano-thermotherapy. In addition to demonstrating the superior cytotoxic effect of such nano-thermotherapy over the conventional exogenous heating by metal bath, more importantly, the sustainable release of melatonin from the Melatonin-MNPs can be greatly promoted upon responsive to the magnetic heating. The multimodality treatment based on Melatonin-MNPs can lead to more significant decrease in cell viability than any single treatment, suggesting the potentiated effect of melatonin on the cytotoxic response to nano-thermotherapy.ConclusionThis study is the first to fabricate the precisely engineered melatonin-loaded multifunctional nanocomposite particles and demonstrate the potential in breast cancer target multimodality treatment.

Characterization of Fe3O4@CS@NMDP magnetic nanoparticles with core–shell structure prepared by chemical cross-linking method

The core–shell structure composite magnetic nanoparticles (NPs), Fe3O4@chitosan@nimodipine (Fe3O4@CS@NMDP), were successfully synthesized by a chemical cross-linking method in this paper. NMDP is widely used for cardiovascular and cerebrovascular disease prevention and treatment, while CS is of biocompatibility. The composite particles were characterized by an X-ray diffractometer (XRD), a Fourier transform infrared spectroscopy (FT-IR), a transmission electron microscopy (TEM), a vibrating sample magnetometers (VSM) and a high performance liquid chromatography (HPLC). The results show that the size of the core–shell structure composite particles is ranging from 12[Formula: see text]nm to 20[Formula: see text]nm and the coating thickness of NMDP is about 2[Formula: see text]nm. The saturation magnetization of core–shell composite NPs is 46.7[Formula: see text]emu/g, which indicates a good potential application for treating cancer by magnetic target delivery. The release percentage of the NMDP can reach 57.6% in a short time of 20[Formula: see text]min in the PBS, and to 100% in a time of 60[Formula: see text]min, which indicates the availability of Fe3O4@CS@NMDP composite NPs for targeting delivery treatment.

Evaluating the performance of citric acid as stabilizer and doping agent in an environment friendly approach to prepare electromagnetic nanocomposite particles

The objective of this investigation is to find a less‐expensive and less‐toxic environmentally benign route for the preparation of magnetic PANI nanocomposite particles. For this citric acid, a weak organic tricarboxylic acid has been used during seeded chemical oxidative polymerization of aniline in presence of variable amounts of Fe3O4 nanoparticles. Nanosized Fe3O4 particles are first prepared by co‐precipitation of Fe2+ and Fe3+ from their alkaline solutions. Then in the second step, magnetic nanocomposite particles—named as Fe3O4/PANI—are prepared by seeded chemical oxidative polymerization of aniline using ammonium persulfate (APS) as oxidant. Independent of Fe3O4 content, Fe3O4/PANI nanocomposite particles possessed comparable high electrical conductivity having the same magnitude as HCl‐doped PANI particles (2.13 × 10−3 S/cm). This result suggested that addition of citric acid during seeded chemical oxidative polymerization not only promoted solubilization of aniline but also functioned as stabilizer and doping agent. Iron oxide content critically influenced the stability, morphology, and magnetic properties of the produced nanocomposite particles. The saturation magnetization and magnetic susceptibility increased with the increase of Fe3O4 content. The nanocomposite particles prepared with core/shell ratio of 0.6/1 (w/w) exhibited the strongest paramagnetism and aligned into fiber‐like structure. The analysis of electromagnetic properties and spectral data from FTIR, X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and thermogravimetry (TG) confirmed the complete coverage of Fe3O4 nanoparticles by PANI layer. POLYM. COMPOS., 39:4628–4636, 2018. © 2017 Society of Plastics Engineers

Composite Magnetic Nanoparticles (CuFe2O4) as a New Microsorbent for Extraction of Rhodamine B from Water Samples

In this work, novel composite magnetic nanoparticles (CuFe2O4) were synthesized based on sol-gel combustion in the laboratory. Next, a simple production method was optimized for the preparation of the copper nanoferrites (CuFe2O4), which are stable in water, magnetically active, and have a high specific area used as sorbent material for organic dye extraction in water solution. CuFe2O4 nanopowders were characterized by field-emission scanning electron microscopy (SEM), FTIR spectroscopy, and energy dispersive X-ray spectroscopy. The size range of the nanoparticles obtained in such conditions was estimated by SEM images to be 35-45 nm. The parameters influencing the extraction of CuFe2O4 nanoparticles, such as desorption solvent, amount of sorbent, desorption time, sample pH, ionic strength, and extraction time, were investigated and optimized. Under the optimum conditions, a linear calibration curve in the range of 0.75-5.00 μg/L with R2 = 0.9996 was obtained. The LOQ (10Sb) and LOD (3Sb) of the method were 0.75 and 0.25 μg/L (n = 3), respectively. The RSD for a water sample spiked with 1 μg/L rhodamine B was 3% (n = 5). The method was applied for the determination of rhodamine B in tap water, dishwashing foam, dishwashing liquid, and shampoo samples. The relative recovery percentages for these samples were in the range of 95-99%.

RETRACTED ​ARTICLE: Synthesis of Magnetic Composites Based on Waste Low Density Polyethylene Wax and Iron Oxide Nanoparticles for Methyl Green Adsorption

Magnetic nanoparticle composites were prepared from iron oxide (magnetite) (Fe3O4) and waste low density polyethylene wax (WLDPEW) via gamma irradiation technique using 60Co source, followed by anchoring Fe3O4 on the surface of WLDPEW samples to produce WLDPEW–Fe3O4 nanoparticle magnetic composite pellets. The outcome WLDPEW and WLDPEW–Fe3O4 nanoparticle magnetic composite pellets were characterized by Fourier transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscope-energy dispersive X-ray spectrometry, high resolution transmission electron microscopy (HR-TEM) and electron spinning resonance (ESR). The results of HR-TEM and XRD showed that the presence of Fe3O4 nanoparticles. HR-TEM photomicrographs of the Fe3O4 into WLDPEW showed that the nanoparticles of Fe3O4 have the average diameter ranged from ~30 to ~50 nm. The EDS spectra showed strong peaks of Fe and O. The ESR spectra exposed the paramagnetic properties of WLDPEW–Fe3O4 nanoparticle magnetic composite pellets. The WLDPEW–Fe3O4 nanoparticle magnetic composite pellets were exploited in adsorption of methyl green dye from aqueous solutions at various conditions. The kinetics and the adsorption isotherms were studied. Through results it was observed that the adsorption capacity of WLDPEW–Fe3O4 nanoparticle magnetic composite pellets is 18.5 mg g−1. Therefore, WLDPEW–Fe3O4 nanoparticle magnetic composite pellets could be used in removing dyes from their aqueous solutions.

Ingenious route for ultraviolet-induced graft polymerization achieved on inorganic particle: Fabricating magnetic poly(acrylic acid) densely grafted nanocomposites for Cu2+ removal

In this study, ultraviolet (UV)-induced graft technology is improved to be successfully applied on inorganic substrate for fabricating a novel poly(acrylic acid) (PAA) brushes-decorated magnetic nano-composite particles (g-MNPs) as a potential adsorbent toward Cu2+ ion. The most fascinating features of the resultant g-MNPs are the abundant and highly accessible carboxyl groups present in PAA brushes and the rapid separation from the medium by magnetic field after adsorption. Through the new and high-efficiency surface-initiated polymerization route, the densely PAA brushes was successfully immobilized on the MNPs surface with a high grafting yield of 88.3%. Excitingly, the g-MNPs exhibited an exceptional performance for Cu2+ adsorption, e.g., ultrahigh adsorption capacity (up to 152.1mgg−1), rapid adsorption rate (within 30min) and low residual concentration (below 1.3ppm). Full kinetic and isotherm analysis as well as thermodynamic study were also undertaken, the results showed that Cu2+ adsorption followed Langmuir isotherm and the pseudo-second-order kinetic model, the adsorption rate was controlled by two sequential periods of external and intraparticle diffusion. According to the calculated value of thermodynamic parameters, the Cu2+ adsorption onto g-MNPs was a spontaneous endothermic process. Furthermore, the excellent reusability of the resultant adsorbent was also confirmed, which can keep above 95% adsorption capacity and desorption rate in 8 consecutive cycles.