Synthesis Of Cobalt Ferrite Nanoparticles Research Articles

Synthesis of cobalt ferrite nanoparticles with different morphologies via thermal decomposition approach and studies on their magnetic properties

Abstract CoFe2O4 nanoparticles have received immense attention in recent times due to their interesting magnetic properties and they possess good thermal and chemical stability. In the present study, CoFe2O4 nanoparticles have been synthesized via a novel thermal decomposition approach using Co–Fe glycolate precursors. The Co–Fe glycolates were prepared by refluxing the corresponding metal salts in ethylene glycol. The morphology of CoFe2O4 nanoparticles can be tailored by varying the synthesis temperature of Co–Fe glycolates and also the amount of ethylene glycol used. The morphology of CoFe2O4 changes from nanorods to hexagonal particles on changing the synthesis temperature of Co–Fe glycolates from 160 °C to 220 °C, On the other hand, on increasing the amount of ethylene glycol while keeping the synthesis temperature constant (220 °C), the morphology of CoFe2O4 nanoparticles changes from hexagons to octahedra. The Co–Fe glycolates and the CoFe2O4 nanoparticles were characterized using several analytical techniques. The magnetic properties of CoFe2O4 nanoparticles were studied by vibrating sample magnetometry. The CoFe2O4 nanoparticles exhibit high coercivity at 5 K with moderate saturation magnetization.

Co-PRECIPITATION SYNTHESIS, CHARACTERIZATION OF CoFE2O4 NANOMATERIAL AND EVALUATION OF ITS TOXICITY BEHAVIOR ON HUMAN LEUKEMIA CANCER K562 CELL LINE

In this study, cobalt ferrite nanomaterial with inverse spinel structure was synthesized via a co-precipitation method using Co(NO3)3.6H2O and Fe(NO3)3.9H2O. A 15% NH4OH solution was used as an alkaline agent for pH adjustment. Oleic acid was used as a coating agent on the surface of the synthesized cobalt ferrite nanoparticles. PXRD analysis confirmed that the obtained material had a main CoFe2O4 cubic crystal structure with space group Fd-3m and lattice parameters a=b=c= 8.40 A (JCPDS standard card no = 01-077-0426). According to the SEM analysis, the pseudo-spherical particles size distribution and morphology of the as-synthesized nanomaterial were homogeneous. The magnetic behavior of the obtained material was analyzed by vibrating-sample magnetometer (VSM). Besides, anti-cancer effect of the as-synthesized cobalt ferrite nanoparticles was examined on an experimental model of acute myeloid leukemia (CML) K562 cell line for the first time. Inhibition of cell growth and cytotoxicity (apoptosis) that are characteristics features of cobalt ferrite nanoparticles are tested on K562 cell line. The results showed growth and viability inhibition and induction of apoptosis in K562 cells treated with the nanoparticles.

Cobalt ferrite nanoparticles for bimodal hyperthermia and their mechanistic interactions with lysozyme

Magnetic nanoparticles find several applications in cancer therapy. We have synthesized cobalt ferrite nanoparticles (CFNPs) and evaluated them as agents for magnetic hyperthermia (MH) effect. The CFNPs were well characterized for size and morphology using TEM, FESEM, and DLS. They were in the size range 8–25 nm with a roughly spherical shape. They were ferrimagnetic with a saturation magnetization of 42 emu/g. They showed a temperature increase of 38 °C when exposed to an alternating magnetic field, and also showed photothermal effect. These two modes of heating along with magnetic targeting make these CFNPs a suitable candidate for biomedical applications. Their interaction with the protein lysozyme was also investigated. UV/visible and fluorescence spectroscopy showed that the CFNPs bind strongly to the protein with the binding constant of the order 105. Time-resolved fluorescence studies validated binding between them. CD spectroscopy showed that protein's conformation changed upon binding to CFNPs with a decrease in the percentage of α-helix. Molecular docking studies were performed to find out the site of binding in the protein.

Synthesis and Characterization of CoFe2O4/MWCNTs Nanocomposites and High-Frequency Analysis of Their Dielectric Properties

Nanoparticles of CoFe2O4 were synthesized by chemical co-precipitation method. The CoFe2O4/MWCNT nanocomposites were synthesized with increasing contents of MWCNTs, i.e., 0.0, 2.0, 3.0, and 5.0% by weight via ultrasonication method in a dispersive medium using ortho-xylene. The synthesized cobalt ferrite nanoparticles and their nanocomposites were characterized by impedance analyzer, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and x-ray diffraction (XRD) techniques. The XRD indexed patterns confirmed the face-centered cubic structure of CoFe2O4/MWCNT nanocomposites. The average crystallite size in all the samples was in the range of 15 to 35 nm. The decorations of CoFe2O4 on MWCNTs were confirmed by SEM images. The FTIR results showed two vibrational bands. With the increasing contents of multi-walled carbon nanotubes in the cobalt ferrite/MWCNT nanocomposites, the dielectric properties were also enhanced. At 1 MHz, dielectric constant, dielectric loss, and tangent loss factor were increased from 26, 15.1, and 0.580 for pure cobalt ferrite to 47, 28.9, and 0.614 for loading of 5% MWCNTs, respectively. At 1 GHz, dielectric constant, dielectric loss, and tangent loss factor were increased from 11.6, 0.33, and 0.028 for pure cobalt ferrite to 19.4, 0.61, and 0.031 for loading of 5% MWCNTs, respectively. Such a huge increase in the dielectric properties of cobalt ferrite and multi-walled carbon nanocomposites exploited their applications at high frequency.

Structural and Magnetic properties of Cobalt Ferrite (CoFe2O4) Nanoparticles by Sol-Gel Technique using Yeast

The aim of the present work is to synthesize cobalt ferrite nanoparticles by sol-gel technique using yeast. The source culture is prepared using yeast, carbon and nitrogen. Three samples are prepared by mixing the source culture with ferric nitrate (0.2 M) and cobalt nitrate (0.15, 0.2, 0.25M) and stirred for suitable duration to get the gel. The final product is heated at 600°C to get the cobalt ferrite nanopowder. Structural analysis reveals the cubic phase of cobalt ferrite nanoparticles with the peaks corresponding to the plane (220), (311), (400), (511) and (440) matches with the PDF data. The peaks are sharp showing the crystalline nature of the prepared samples. From the microstructural parameters calculated for the prominent peak (311) shows the average crystallite size is 44 nm. The lattice constant is found to be around 8.350 Å which is close to the bulk value of cobalt ferrite nanoparticle (8.373Å). The calculated X-ray density is more than their bulk counterpart and is attributed to the formation of pores throughout the synthesis method. FTIR analysis shows the existence of functional groups within the prepared sample. EDAX analysis shows the rise in the atomic weight percentage of cobalt with increase in weight proportion of cobalt nitrate. SEM analysis shows the surface morphology of the prepared sample and the ferromagnetic behavior of the cobalt ferrite nanoparticle is observed by VSM studies.

Elimination of Escherichia coli in Water Using Cobalt Ferrite Nanoparticles: Laboratory and Pilot Plant Experiments.

This paper focuses on the synthesis of cobalt ferrite nanoparticles by the sol–gel method and their photocatalytic activity to eliminate bacteria in aqueous media at two different scales: in a laboratory reactor and a solar pilot plant. Cobalt ferrite nanoparticles were prepared using Co(II) and Fe(II) salts as precursors and cetyltrimethyl ammonium bromide as a surfactant. The obtained nanoparticles were characterized by X-ray diffraction, scanning and transmission electron microscopy. Escherichia coli (E. coli) strain ATCC 22922 was used as model bacteria for contact biocidal analysis carried out by disk diffusion method and photocatalysis under an ultraviolet A (UV-A) lamp for laboratory analysis and solar radiation (radiation below 350 W/m2 in a typical cloudy day) for the pilot plant analysis. The results showed that cobalt ferrite nanoparticles have an average diameter of (36 ± 20) nm and the X-ray diffraction pattern shows a cubic spinel structure. Using the disk diffusion technique, it was obtained inhibition zones of (17 ± 2) mm diameter. Results confirm the photocatalytic elimination of E. coli in water samples with remaining bacteria below 1% of the initial concentration during the experiment time (30 min for laboratory tests and 1.5 h for pilot plant tests).

Methylene blue loaded, silica coated cobalt ferrite nanoparticles with potential for combination therapy

We have synthesized cobalt ferrite nanoparticles (CFNPs), and evaluated them as agents for photothermal therapy. With a further coating of a layer of silica on the nanoparticles (SCNPs) using Stober process, the loading of a photosensitizer, methylene blue (MB), was achieved. The size and morphology of particles were characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), and dynamic light scattering (DLS). All these showed an increase in size from CFNPs to SCNPs, suggesting successful coating of silica. The formation of silica layer was confirmed using elemental analysis and Fourier transform infrared (FTIR) spectroscopy. The particles were ferromagnetic in nature, as obtained using vibrating sample magnetometry (VSM). The effective concentration of MB in particles, obtained using UV/Visible Spectroscopy, was 12 μM. The photo-induced hyperthermia experiment of CFNPs resulted in rise in temperature by eleven degrees. The use of the formulated particles in photodynamic therapy (PDT) was studied using singlet oxygen (1O2) photobleaching assay. This confirmed that particles generated 1O2 upon light irradiation, and its efficiency is comparable to that of free MB. Both the therapies combined together with magnetic targeting can give these particles potential to be used in localized cancer treatment.

Synthesis of cobalt ferrite nanoparticles via chemical precipitation as an effective photocatalyst for photo Fenton-like degradation of methylene blue

Synthesis of cobalt ferrite nanoparticles via chemical precipitation as an effective photocatalyst for photo Fenton-like degradation of methylene blue

In vitro biocompatibility and hyperthermia studies on synthesized cobalt ferrite nanoparticles encapsulated with polyethylene glycol for biomedical applications

Abstract The magnetic cobalt ferrite nanoparticles (CoFe2O4) were synthesized by sol-gel combustion technique and encapsulated with polyethylene glycol (PEG). The phase formation and crystalline nature were confirmed by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). The microstructure and elemental composition were characterized using Scanning Electron Microscopy (SEM). Magnetic characteristics of the synthesized sample were studied at room temperature using Vibrating Sample Magnetometer (VSM) and its low coercivity value indicates that these nanoparticles are near the superparamagnetic limit. Hyperthermic behavior and cell biocompatibility characteristics with human leucocyte culture were analyzed and results signify that synthesized cobalt ferrite (CoFe2O4) nanoparticles encapsulated with Polyethylene glycol (PEG) are one of the potential candidates for hyperthermia, targeted drug delivery and various other biomedical applications.

Facile synthesis of cobalt ferrite nanoparticles (CFO-NPs) as anode material with enhanced lithium storage capability

In this work, CoFe2O4 spinel phase nanoparticles (CFO-NPs) with an average diameter of 80 nm were synthesized through facile urea combustion method, which can be extended for the large scale fabrication of nanoparticles. The obtained product is characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Brunauer Emmett and Teller (BET) and X-ray photoelectron spectroscopy (XPS). When CFO-NPs are used as an anode material for Li-ion battery, it show excellent electrochemical performance due to its typical nano-sized particles, which results excellent diffusion of electrolyte ions and ensured the fast electron transportation. As a result, CFO-NPs show excellent initial charge and discharge capacities of 1506 and 1524 mA h g−1, respectively. After fifty cycles, the discharge capacity still remains at 896 mA h g−1 at a current density of 100 mA g−1, and excellent rate capability. Given their excellent electrochemical performance, the CFO-NPs considered as a promising anode material for Li-ion batteries.

Combustion Synthesized Cobalt Ferrite Nanoparticles as Magnetically Recyclable Catalyst for Synthesis of Benzimidazole Derivatives

Combustion Synthesized Cobalt Ferrite Nanoparticles as Magnetically Recyclable Catalyst for Synthesis of Benzimidazole Derivatives

Study of structural phase transformation and hysteresis behavior of inverse-spinel α-ferrite nanoparticles synthesized by co-precipitation method

Abstract Substitution of cobalt (Co2+) ions in cobalt ferrite (CoFe2O4) with copper (Cu2+) and aluminum (Al3+) ions allows variations in their electric and magnetic properties which can be optimized for specific applications. In this article, synthesis of inverse-spinel Co1−xCuxFe2−xAlxO4 (0.0 ≤ x ≤ 0.8) nanoparticles by substituting Cu2+ and Al3+ ions in CoFe2O4 via co-precipitation method is reported. By controlling copper and aluminum (Cu-Al) substituent ratio, the magnetic moment and coercivity of synthesized cobalt ferrite nanoparticles is optimized. The role of substituents on the structure, particle size, morphology, and magnetic properties of nano-crystalline ferrite is investigated. The Co1−xCuxFe2−xAlxO4 (0.0 ≤ x≤ 0.8) nanoparticles with crystallite size in the range of 23.1–26.5 nm are observed, 26.5 nm for x = 0.0–23.1 nm for x = 0.8. The inverse-spinel structure of synthesized Co1−xCuxFe2−xAlxO4 (0.0 ≤ x ≤ 0.8) nano-particles is confirmed by characteristic vibrational bands at tetrahedral and octahedral sites using Fourier transform infrared spectroscopy. A decreases in coercive field and magnetic moment is observed as Cu-Al contents are increased (x = 0.0–0.8). The positive anisotropy of synthesized particles Co1−xCuxFe2−xAlxO4 (0.0 ≤ x ≤ 0.8) is obtained in the range 1.96 × 105 J/m3 for x = 0.0 to 0.29 × 105 J/m3 for x = 0.8.

Synthesis and Characterization of Folate‐decorated Cobalt Ferrite Nanoparticles Coated with Poly(Ethylene Glycol) for Biomedical Applications

A stable and biocompatible targeting complex CFNs@PEG‐FA is developed. The initially synthesized cobalt ferrite nanoparticles (CFNs) were treated with poly(ethylene glycol) (PEG) in order to improve biocompatibility of the CFNs. Citric acid (CA) was used as the coupling agent, which made PEG to bond with the CFNs. CFNs@PEG were conjugated with folic acid (FA) to synthesize CFNs@PEG‐FA, which was capable of targeting the FA receptor positive (FAR+) cancer cells. Synthesized nanoparticles were physically and chemically analyzed using EDX, FT‐IR, XRD, TGA, FESEM, TEM, DLS, and VSM. The biocompatibility of CFNs@PEG‐FA was assessed in vitro on HSF 1184 (human skin fibroblast cells) and HeLa (human cervical cancer cell, FAR+) using MTT assay and AO/EB staining florescence method. High level of CFNs@PEG‐FA binding to HeLa was confirmed through quantitative and qualitative in vitro targeting studies. Results show that CFNs@PEG‐FA can be a potential biomaterial for use in biomedical trials, especially magnetic hyperthermia. The findings through this in vitro study are to be compared in future with those of in vivo studies.

Okra extract-assisted green synthesis of CoFe2O4 nanoparticles and their optical, magnetic, and antimicrobial properties

Cobalt ferrite nanoparticles are synthesized using biological agents as fuel by both conventional and microwave heating methods. We focused on the green synthesis of cobalt ferrite, which is eco friendly, inexpensive, and easy to produce by large-scale synthesis. Synthesis methods were carried out under the same conditions. The role of the plant extract and advantages of microwave techniques are discussed. Plant extract-mediated nanoparticles were characterized by various techniques to analyze the size, shape, crystallinity, optical, magnetic, and antimicrobial properties. The X-ray diffraction pattern revealed single-phase crystalline structures with an average size of 45–55 nm. The functional groups present in the samples were confirmed by Fourier transform infrared spectroscopy. From SEM and DLS studies, it is confirmed that the spherical nanoparticles range in the size of 300–500 nm for CHM and 5–50 nm for MHM. Energy-dispersive X-ray spectroscopy analysis confirmed the presence of cobalt, iron, and oxygen. The energy band gap of the samples was measured by UV–Visible diffuse reflection spectroscopy. In photoluminescence analysis, the band emission was observed in the visible region. Samples prepared by microwave heating showed better magnetic behavior than those prepared by conventional heating based on vibrating sample magnetometer analysis. The plant extract makes the synthesis of cobalt ferrite nanoparticles a potentially low-cost and ecofriendly remediation method. The synthesized nanoparticles also exhibited excellent antimicrobial activity against bacteria and fungus strains.

Influence of reaction temperature, proportions of iron, cobalt and KOH on the CoFe2O4 synthesis by hydrothermal method assisted by microwave heating

In this study, several factors such as reaction temperature, proportions of iron, cobalt and KOH were considered in the synthesis of cobalt ferrite nanoparticles by hydrothermal method assisted by microwave radiation. These parameters were studied using the full factorial experiment design. The effect of these factors on crystallite size was investigated using surface response methodology. The structure, crystallite size, magnetic properties, degree of inversion, as well as the chemical occupation of Fe ions were investigated in this study. The results indicated that all factors were statistically significant by analysis of variance (F-test), with a confidence level of 95%. The factors that influenced the growth of the crystallite were: KOH and iron concentration, precursors of cobalt salts and the effect of the interaction between the concentration of KOH and the concentration of precursors. The analysis of variance at a significance level of 95% indicates that the model adjusted to the experimental points is significant.

Sago starch: chelating agent in Sol-gel synthesis of cobalt ferrite nanoparticles

Starch from the stem of sago palm (Metroxylon sagu) was demonstrated as a chelating agent in the sol-gel synthesis of cobalt ferrite (CoFe2O4) nanoparticles. Variations in the weight ratio of metal nitrates to sago starch from 1:8 to 1:12 led to the particle size of 30–500 nm. However, further increase in sago starch to 1:16 resulted in ferrimagnetic hysteresis loops with a reduced coercive field and magnetization due to the second phase of hematite (α-Fe2O3). The synthesis conditions and products were comparable to those of the polyvinyl alcohol (PVA) sol-gel synthesis. Thus, sago starch can be implemented in the green synthesis of nanosized ferrites whose magnetic properties are tuned by varying of sol-gel compositions for each application.

Synthesis of cobalt ferrite nanoparticles by constant pH co-precipitation and their high catalytic activity in CO oxidation

A series of cobalt ferrite samples were synthesized from a metal nitrate solution at constant pH between 9 and 12 by the controlled co-precipitation method without any surfactant.

Synthesis of cobalt ferrite nanoparticles by means of confined impinging-jets reactors.

The process of cobalt ferrite synthesis by means of confined impinging jets was studied experimentally at relative low temperatures (20°C to 30°C) and ambient pressure. Unlike hydrothermal synthesis usually performed at high pressures and temperatures (400°C to 450°C), impinging jets synthesis allows to produce small particles (approx. 8 nm mean size) within few milliseconds in a continuous flow. Due to short contact of reagents heir fast and effective mixing it was possible to avoid co-products formation and to exclude the growth of crystallines. Ability to control stable and effective hydrodynamics and the fast separation of products from co-products results in the optimal conditions for fast reaction of precipitation practically excluding building of large particles and aggregates.

Copper-substituted cobalt ferrite nanoparticles: Structural, optical and antibacterial properties

Economic and simple co-precipitation technique was used to synthesize cobalt ferrite nanoparticles (CuxCo(1-x)Fe2O4) where x = 0.0, 0.3, 0.5, 0.7 and 1.0. We systematically studied the crystal structure and antibacterial properties of samples as a function of Cu-substituted content. Increasing Cu concentration causes decrease in the nanoparticle size from ~30 to ~20 nm. Specific saturation magnetization (Ms), remanent magnetization (Mr) and coercivity (Hc) of the spinel ferrites are diminished by the substitutions of Cu+2 ions. FTIR spectra exhibit two prominent fundamental absorption bands at ~595 cm-1 and 419 cm-1. These bands correspond to intrinsic stretching vibrations of metal at tetrahedral and octahedral site respectively. The Raman scattering results reveal that increase in the Cu content enhances the local disorder at both tetrahedral and octahedral sub lattices. Moreover, we found that substitution of cobalt with copper leads to high reactive oxygen species (ROS) which in turn enhance the antibacterial ability, as exhibited by optical density and inhibition zone diameter (IZD). The results indicate that the substitution of Co with Cu in Co ferrite nanoparticles strongly influences the microstructure, crystal structure and particle diameter.

Preparation and characterization of nanosized cobalt ferrite particles by co-precipitation method with citrate as chelating agent

Cobalt ferrite (CoFe2O4) nanoparticles were synthesized by a facile novel co-precipitation method with citrate as chelating agent. The synthesized cobalt ferrite nanoparticles were calcinated at 400, 600 and 800 °C and characterized by using XRD and TGDTA. From XRD it confirms that CoFe2O4 nano particles belongs to spinel type lattice of space group Fd3m. The CoFe2O4 nano particles calcinated at 600 °C were further characterized by using FE-SEM with EDAX, FE-TEM with SAED pattern, DLS zeta potential and CV. The linear relationship between particle size and calcination temperatures of CoFe2O4 nanoparticles was noticed. The surface morphology of CoFe2O4 studied through FE-SEM and FE-TEM indicate that the particles are found crystalline and are in cubic shape. EDAX analysis revealed the presence of Co, Fe and O. Zeta potential exposes the good stability of the prepared CoFe2O4 nanoparticles. Capacitance value 609 F g−1 was observed for the scanning rate of 2 mV s−1 from the CV study and concluded it is suitable for super capacitor application.