Size Of Fe3O4 Research Articles

Thermal conductivity and photothermal characteristic of core-shell Fe3O4@C nanofluids in different particle size

Instability is a key issue that limits the application of magnetic nanofluids. In this study, Fe3O4@C nanoparticles were obtained using a carbon layer coated with a ferromagnetic material, which improved the instability of the magnetic nanofluid while obtaining higher thermal conductivity and showed excellent photothermal conversion performance in photothermal conversion experiments. Firstly, we prepared Fe3O4@C nanoparticles via the solvothermal method. We then compared different sizes of Fe3O4@C nanoparticles in terms of structure, composition, heat transfer characteristics and photothermal efficiency. The results indicate that contrary to the conventional belief that smaller nanoparticles have higher thermal conductivity, the 90.30 nm Fe3O4@C nanofluids has better thermal conductivity than 58.17 nm due to its larger proportion of carbon shells. In the photothermal conversion experiment for DASCs, the 58.17 nm group performed best, with the temperature of the 0.2 wt% sample reaching 45.80 °C and a photothermal efficiency of 60.32%.

Precise engineering of Fe3O4/MWCNTs heterostructures for high-performance supercapacitors

The development of electrode materials with well-defined interfaces plays a vital role on improving the electrochemical performance of supercapacitors. The hybridization of conductive carbon materials with metal oxides is recommended to fabricate improved supercapacitor electrodes. In this work, catalytic chemical vapor deposition (CCVD) and solvothermal methods were utilized to synthesize a Fe3O4/MWCNTs heterostructure with tuned size and morphology. The heterostructure-based electrode showed supreme specific capacitance, energy density, and cycling stability. The size of Fe3O4 as well as the diameter and the number of walls of the functionalized MWCNTs were optimized. Various characterization techniques such as Scanning Electron Microscopy (SEM) combined with Energy Dispersive X-ray (EDX) spectroscopy, Transmission Electron Microscopy (TEM), X-ray diffraction spectroscopy (XRD), and Raman Spectroscopy were utilized to explore the structural and surface properties of the engineered heterostructures. The electrochemical measurements were carried out in 6 M KOH for all synthesized electrodes. The Fe3O4/MWCNTs heterostructure showed a specific capacitance of 492.3 F/g, energy density of 115.55 Wh/Kg at 1 A/g, and capacitance retention of 165.7 % after 1000 cycles. The specific capacitance of the electrodes was further calculated using CV measurement achieving 921.3 F/g at 10 mV/s for the Fe3O4/MWCNTs heterostructure. The excellent electrochemical performances of MWCNTs/Fe3O4 heterostructures were mainly due to the homogenous distribution of Fe3O4 nanoparticles with multivalent oxidation states on the surface of MWCNTs. This led to faster surface oxidation-reduction reactions and consequently, higher reversible capacity and ultrahigh energy density in addition to improved cyclability. This work sheds light on the possibility of precisely controlling Fe3O4/MWCNTs heterostructure electrodes for high-performance energy storage applications.

"One-pot" preparation of aminated carbon nanotube-modified magnetic nanoparticles and their application to the quantification of phenoxyacetic acid herbicides in cereal and vegetable samples

有效萃取是分析复杂样品中苯氧羧酸类除草剂(PAs)残留的关键步骤。为此,该文利用“一锅法”水热技术快速、简便地制备了氨基碳纳米管功能化磁性纳米粒子(NH2-CNTs@M)并作为磁固相萃取(MSPE)的萃取介质,用于萃取谷物和蔬菜样品中痕量PAs。研究利用多种手段对NH2-CNTs@M的形貌、尺寸、磁性性质等进行了表征,结果表明Fe3O4的粒径、氨基化碳纳米管的直径以及NH2-CNTs@M的磁饱和值分别为30 nm、40 nm和44.2 emu/g。详细考察了制备条件和萃取参数对NH2-CNTs@M/MSPE萃取性能的影响,结果表明,NH2-CNTs@M/MSPE可通过π-π、疏水和氢键作用有效富集目标化合物,最佳萃取条件如下:吸附剂用量为30 mg,解吸溶剂为含2.0%(v/v)甲酸的乙腈溶液,吸附时间和解吸时间分别为8.0 min和3.0 min,基底pH值为6.0,不调节基底的离子强度。将NH2-CNTs@M/MSPE与高效液相色谱-二极管阵列检测技术(HPLC-DAD)联用,建立了谷物和蔬菜中PAs的灵敏检测方法。谷物和蔬菜基质中苯氧羧酸类除草剂的检出限(LOD, S/N=3)分别为0.32~1.6 μg/kg和0.53~1.6 μg/kg,定量限(LOQ, S/N=10)分别为0.94~4.8 μg/kg和1.6~4.8 μg/kg。在两种实际样品中不同浓度下的加标回收率分别为73.1%~112%和72.3%~113%。与现有方法相比,所建方法具有萃取速度快、灵敏度高和环境友好等特点。

Nanocrystalline Formation and Magnetic Properties in Fe₂O₃-C System by Mechanical Alloying.

The effect of mechanical alloying (MA) on the solid state reaction of hematite and graphite system with a positive reaction heat was investigated using a mixture of elemental Fe₂O₃-C powders. The solid state reduction of hematite to Fe₃O₄ has been obviously observed after 3 hours of MA by a vibrating ball mill. A two-phase mixture of Fe₃O₄ and remaining Fe₂O₃ is obtained after 5 hours of MA. Saturation magnetization gradually increases with MA time due to the formation of Fe₃O4 and then reaches 23 emu/g after 5 hours of MA. In addition, a Fe₃O₄ single phase is obtained by MA after 3 hours and subsequently heat treated up to 700°C. X-ray diffraction result shows that the average grain size of Fe₃O₄ prepared by MA for 5 hours and heat treatment to be in the range of 92 nm. The saturation magnetization of Fe₃O₄ prepared by MA and heat treatment reaches a maximum value of 56 emu/g for 5 hours MA sample. It is also observed that the coercivity of 5 hours MA sample annealed at 700 °C is still high value of 113 Oe, suggesting that the grain growth of magnetite phase during annealing process tends to be suppressed.

Synthesis, Characterization, and Photodegradation Activity of Fe3O4@ZnO Nanoflowers

Technological advancement nowadays is detrimental to the environment. To deal with such a problem, waste decomposition should be carried out to produce a clean and healthy environment. In this study, the photodegradation method was used because it has advantages in efficiency and stability. The material used as a photodegradation catalyst was Fe3O4@ZnO nanoflowers. The synthesis of Fe3O4@ZnO nanoflowers was carried out using coprecipitation method for Fe3O4 and precipitation for composites. The variations in the mass of the catalyst used in this study were 50, 100, and 150 mg. The samples were characterized using an X-Ray Diffractometer (XRD) to analyze the phase, size, and crystal structure, Scanning Electron Microscopy (SEM) to determine morphology, and a photodegradation test to measure the photodegradation activity. The grain sizes of Fe3O4 and ZnO nanoflowers based on the Scherrer equation were 12.12 nm and 32.29 nm, respectively. Based on SEM characterization, the morphology of Fe3O4@ZnO nanoflowers showed a flower-like structure with an average diameter of 3.2 µm. The best performance of phenol photodegradation activity is 54.3 % obtained in the first cycle of 150 mg Fe3O4@ZnO nanoflowers under solar irradiation.

Rapid Adsorption of Magnetite Nanoparticles from Recycled Mill Scale Waste as Potential Adsorbent for Removal of Cu(II) Ions

The present study was conducted to establish adsorbent potential of magnetite nanoparticle ferrous ferric oxide (Fe3O4) for removal of Cu(ll) ions in wastewater. In the study, Fe3O4 was prepared by synthesizing low-cost recycled mill scale waste in an aqueous solution. Samples of scale wastes were milled and ground using high-energy ball milling (HEBM) at three milling times of 5, 7 and 9 hours. Extraction of Fe3O4 was accomplished by magnetic separation technique (MST) and Curie temperature separation technique (CTST). The morphologies and structural properties of Fe3O4 were characterized by using X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and Fourier-transform infrared spectroscopy (FTIR). HRTEM yielded images in the range of 10-22 nm. Maximum adsorption capacity, qe,and percentage removal of Cu(II) ions were achieved at 4.45 mg/g and 62.61% respectively after 7 hours of milling time. The present study recorded the smallest particle size of Fe3O4 imparting high qe, and percentage removal of Cu (II) ion in an aqueous solution, suggesting its high adsorbent potential.

Preparation and characterization of an effective microwave absorbent: RGO-MoS2-Fe3O4 nanocomposite

Reduced graphene oxide-molybdenum disulfide (RGO-MoS2) loaded Fe3O4 nanoparticles composite (RGO-MoS2-Fe3O4) is prepared via two-step hydrothermal reaction. RGO-MoS2 possesses three dimension architecture structures. This structure can prevent RGO and MoS2 nanosheets restacked together and provide substrates for the Fe3O4 nanoparticle decoration. The sizes of Fe3O4 are in the range of 5–20 nm. As a microwave absorbent: the minimum reflection loss (RL) value is -47.67 dB at 17.44 GHz when the thickness is only 1.5 mm. The absorption bandwidth (RL < −10 dB) can reach 4.72 GHz with the thickness is 1.7 mm. Compared with the previously reported literature, RGO-MoS2-Fe3O4 nanocomposite exhibits excellent microwave absorption performance and can be served as an light-weight microwave absorber.

Composite Nanoparticles and Coated With Hydrogel to Slow Drug Delivery of Cyclophosphamide Test it Against Breast Cancer Cell Lines (GJE, MCF7)

Introduction & Objective: Magnetic nanoparticles have found many applications because of their characteristics such as large surface area, small volume and simple separation with external magnetic field. These characteristics are very critical for drug delivery. In the current study, magnetic nanoparticles of iron oxide have been used as the central core of PAMAM dendrimer. The aim of current study was to evaluate the cytotoxic effects of this dandrimer on cancerous cell lines. Materials and methods: magnetic nanoparticles were synthesized through the co-precipitation method and its size was measured by an electron microscope. following, NH2 @ methyl acrylate + ethylintiamine groups were added as branches and hydroxyl group with the negative charge was placed on the end terminus of the dendrimer branchs. The size of the synthesized dendrimer was measured by SEM. In order to investigate the accuracy of the steric bond reaction between the ethylene diamine and methyl acrylate functional groups, a FTIR infrared absorption spectrometer was used to investigate the absorption peak in a range of 1720-1720 nm. In order to release the drug continuously, after loading the methyl Prednisolone drug onto a synthesized nano dendrimer, the entire collection was coated with chitosan quaternary derivative. The absorption spectrum of Prednisolone was measured at 284 nm wavelength (which is the maximum absorption peak) by the UV-visible light absorption device, and the amount of drug release was detected within 24 hours. Finally, the fatal effect of this nano-particle complex on the cancerous types GEJ-MCF 7 was investigated by inverse electron microscopy and the amount of nano-particle toxicity was measured using lactate dehydrogenase Kit and ELISA. Results: Based on the results of the electron microscope, the Fe3O4 size was in the range of 4.79 nm-6.37 nm range, which is smaller than nano-dendrimers with a range of 6.30 nm-43.67 nm. The FT-IR chart for the Methylacrylate @ Ethylendiamin esteric bond was obtained in the range of 1720 and 1730 cm -1. In this chart, the values of 600 cm-1 and 1000 cm-1 were related to Fe3O4 and Fe3O4 @ NH2, respectively. Triethyl Chitosan coated with Nanoparticle @ Drug coated with Nanoparticle @ Drug, along with trimethyl chitosan and glutaraldehyde creates a connection between TMC monomers. In this condition, glutaraldehyde helps to limit the delivery time of the drug. Also, cytotoxicity results indicated that the cell death rate in the incubated media with a complete nano-particle complex was dramatically greater than cell death rate with drug alone as well as nano-particle alone, which expresses the efficacy of the dendrimer-drug + chitosan drug complex. Conclusion: The results indicated that the synthesized nanoparticle complex by the proposed method increased the death rates in the studied cells. In addition, a low dose application of a drug in any nanoparticle compound reduces the side effects of drug, and this method is safe for cancer treatment.

Microstructure, dielectric and enhanced multiferroic properties of Fe3O4/PbZr0.52Ti0.48O3 composite ceramics

Magnetoelectric composite ceramics Fe3O4/PbZr0.52Ti0.48O3 with different molar ratios (Fe3O4/PbZr0.52Ti0.48O3 = 1:1, 1:2 and 1:8) were prepared by combining hydrothermal method and sol–gel method, effects of molar ratio on the structure, dielectric and multiferroic properties were investigated. The results indicate that the synthesized composites show bi-phase structure, ruling out the presence of any obvious impurity phases. The grains can be divided into two types, the larger grain is attributed to PbZr0.52Ti0.48O3 while the smaller one can be considered to be Fe3O4. With the molar ratio increasing, the grain shape of PbZr0.52Ti0.48O3 changes from stripe to bulk-like while the shape and size of Fe3O4 is near the same. Both the dielectric constant and loss decrease with frequency, the specimen with the molar ratio of 1:8 shows the largest dielectric constant, while the sample has the lowest dielectric loss when the molar ratio is 1:2. With the increase of molar ratio, the height of the relaxation peak decreases and the peak position shifts to higher temperature. When the molar ratio is 1:8, the relaxation peak disappears due to less interface polarization. The remnant polarization increases with increasing the molar ratio, the maximum value is 1.12 μC/cm2, obtained at 1 kHz when the molar ratio is 1:8. Anomalous magnetic properties are observed, in which the magnetization increases first and then decreases with molar ratio, the largest saturation magnetization is ~ 30 emu/g when the ratio is 1:2 due to the strong interface interaction. The sample with the ratio of 1:1 shows the largest magnetic loss because of the highest content of magnetic phase. The magnetization shows a monotonic variation behavior with the molar ratio, indicating the strong interface interaction between the two phases. The maximal ME coupling coefficient is about 5.12 mV/(cm.Oe) for the sample 1:2 due to the stronger magnetic and ferroelectric properties.

A Two-Step Strategy for Fabrication of Biocompatible 3D Magnetically Responsive Photonic Crystals.

Extremely stable and biocompatible 3D magnetically responsive photonic crystals (MRPCs) are successfully prepared in aqueous solution. Classic hydrothermal synthesis was applied for preparation of the Fe3O4@C core. Modified Stöber method was then employed for synthesis of the different size of Fe3O4@C@SiO2. Unlike the traditional magnetic nanoparticles, the highly negative charged superparamagnetic nanospheres (SMNs), i.e., the double-shell structure Fe3O4@C@SiO2 are capable of rapidly self-assembling into 3D MRPCs with full visible and various colors that can be periodically and reversibly tuned under different kinds of external magnetic fields (EMFs) within 1 s. The assembling behavior and mechanism of the 3D MRPCs under EMF were monitored and analyzed. The preparation is simple and the size of the SMN is easily controllable by adjusting the amount of catalyst. Compared with the previous works, the synthesized 3D MRPCs are hydrophilic, and exhibit extremely high stability after 6-month storage. To conclude, our study provides an effective two-step strategy for fabrication of biocompatible 3D MRPCs and it reveals great potentials in biological fields.

Visible-Light Induced Photodegradation of Organic Contaminants in Water Using Fe3O4 Nanoparticles Modified Polypyrrole/Fly Ash Cenosphere Composite

Ternary nano-composites of polypyrrole/iron oxide/fly ash cenosphere (PPY/Fe3O4/FAC) were synthesized and used as magnetic photocatalyst. The synergistic effect of FAC, a buoyant carrier and polypyrrole, a conducting polymer enhanced the photocatalytic activity. Different composites were synthesized by varying the concentration of Fe3O4 and FAC to evaluate its effect on the photocatalytic properties of composites. The presence of Fe in Fe2+ and Fe3+ oxidation states at binding energies of 709.3 and 711.4 eV respectively was depicted by XPS curve. PPY/Fe3O4/FAC (1 : 3) composite showed the highest photocatalytic activity with rate constant (k) 0.0058 min–1. The removal efficiency of BPA was found to be around 75% and ~62% total organic content (TOC) was eliminated at optimized conditions from the solution. Transmission electron microscopy (TEM) showed the cluster morphology of the PPY/Fe3O4/FAC nano-composites with ~6–10 nm size of Fe3O4. X-ray diffraction studies elucidated the characteristic peaks of both PPY and Fe3O4 at 2θ ~ 20°–30°, and 26.04°, respectively in the composites which also confirmed the interaction of PPY with Fe3O4.

Kinetic sorption study of Cerium (IV) on magnetite nanoparticles

ABSTRACTMagnetite nanoparticles (Fe3O4) and humic acid-coated magnetite nanoparticles (Fe3O4/HA) were prepared by co-precipitation method for cerium ions removal from aqueous solution. The success of preparation in nanoscale was confirmed by x-ray diffraction (XRD) and transmission electron microscopy (TEM). The TEM image shows that the size of Fe3O4 is around 15 nm and the presence of humic acid reduces the magnetite aggregation and stabilizes the magnetite suspension. Adsorption studies with respect to various process variables such as contact time, pH, and temperature were investigated by batch technique. The sorption kinetics and isotherms of Fe3O4 and Fe3O4/HA for Ce (IV) ions show that the sorption kinetics follow the pseudo-second-order and Langmuir isotherm models for both sorbents. The maximum capacities (Qmax) of Ce (IV) onto Fe3O4 and Fe3O4/HA were found to be 160 and 280 mg/g, respectively. The thermodynamic parameters (ΔGo, ΔHo and ΔSo) were calculated, and the results revealed that the sorption process of Ce (IV) ions on both Fe3O4 and Fe3O4/HA are spontaneous, endothermic for Fe3O4 and exothermic for Fe3O4/HA.

Preparation and evaluation of the effect of Fe3O4@piroctone olamine magnetic nanoparticles on matrix metalloproteinase‐2: A preliminary in vitro study

In the present study, Fe3 O4 magnetic nanoparticles were synthesized by the coprecipitation of Fe(2+) and Fe(3+) ions and used as a nanocarrier for the production of piroctone-olamine-loaded Fe3 O4 nanoparticles (Fe3 O4 @PO NPs). The nanocrystalline structure of the prepared iron oxide species was confirmed by the X-ray diffraction spectroscopy method. Particle size distribution analysis showed that the size of Fe3 O4 @PO NPs was in the range of 5-55nm. The magnetization curve of Fe3 O4 @PO NPs (with saturation magnetization of 28.2emu/g) confirmed its ferromagnetic property. Loading of PO on the surface of Fe3 O4 NPs qualitatively verified by Fourier transform infrared spectrum obtained from Fe3 O4 @PO NPs. Cytotoxicity studies on the human fibrosarcoma cell line (HT-1080) revealed higher inhibitory effect of Fe3 O4 @PO NPs (50% cell death [IC50 ] of 8.1µg/mL) as compared with Fe3 O4 NPs (IC50 of 117.1µg/mL) and PO (IC50 of 71.2µg/mL) alone. In the case of human normal fibroblast (Hs68), the viability percentage was found to be 75% in the presence of Fe3 O4 @PO NPs (120µg/mL). Gelatin zymography showed 17.2% and 34.6% inhibition of matrix metalloproteinase-2 (MMP-2) in the presence of Fe3 O4 @PO and PO, respectively, at the same concentration of 40µg/mL, whereas Fe3 O4 NPs did not inhibit MMP-2 at any concentration.

An improved Stöber method towards uniform and monodisperse Fe3O4@C nanospheres

Significant progress has recently been made in the synthesis of Fe3O4@C nanospheres with uniform, monodisperse and tunable carbon shells. Fe3O4@C nanospheres were obtained by directly carbonizing Fe3O4@polymer which was synthesized by a versatile and economical Stober method with resorcinol and formaldehyde as precursors. The synthesis conditions in the formation of Fe3O4@polymer were systematically investigated. It was found that the yield of the Fe3O4@polymer is highly influenced by the concentration of ammonium hydroxide, and the monodispersity is mainly affected by the concentration of ammonium hydroxide and the citrate group sites outside the surfaces of the Fe3O4 nanospheres. Interestingly, carbonization of Fe3O4@polymer at high temperature makes the grain sizes of Fe3O4 in Fe3O4@C samples larger than those in the Fe3O4 sample, which makes the saturation magnetization value for the Fe3O4@C samples higher than those of common obtained materials. The adsorption performance of Fe3O4@C for anthracene was tested both in water and in cyclohexane solution; it shows fast adsorption rates (about 1 h to reach equilibrium in water and 3 h in cyclohexane solution) and high adsorption capacities (31.5 mg g−1 in water and 2 mg g−1 in cyclohexane solution), which are ascribed to its high uniformity and monodispersity. These make Fe3O4@C an ideal adsorption and enrichment material, especially for polycyclic aromatic hydrocarbons in water and in organic solvents.

Synthesis of M–Nd doped Fe3O4 nanoparticles (M = Co, Ce, Cr, Ni) with tunable magnetic properties

Magnetic nanoparticles were prepared by the aqueous co-precipitation method. The magnetic nanoparticles obtained were characterized systematically through the use of an X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR) and a vibrating sampling magnetometer (VSM). The results revealed that the magnetic nanoparticles were spherical shaped with inverse spinel structure. The size of Fe3O4 and Nd-Co doped Fe3O4 magnetic nanoparticles were approximately 15 nm. Magnetic measurement revealed that the nanoparticles were super paramagnetic at room temperature. It was found that the magnetic response of the Fe3O4 increased when it was doped with Nd3+ and Co2+. However, the magnetic response of the Fe3O4 decreased when it was doped with Nd3+ or Ce3+ or Cr3+or Ni2+. KEYWORDS: Fe3O4, Magnetic nanoparticles, Superparamagnetic, Magnetite, Fe3O4 doped Bull. Chem. Soc. Ethiop. 2013, 27(1), 49-56.DOI: http://dx.doi.org/10.4314/bcse.v27i1.5

Solvothermal in situ synthesis of Fe3O4-multi-walled carbon nanotubes with enhanced heterogeneous Fenton-like activity

Fe3O4-multi-walled carbon nanotubes (Fe3O4-MWCNTs) hybrid materials were synthesized by a solvothermal process using acid treated MWCNTs and iron acetylacetonate in a mixed solution of ethylene glycol and ultrapure water. The materials were characterized using X-ray powder diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. The results showed that a small amount of water in the synthesis system played a role in controlling crystal phase formation, size of Fe3O4, and the homogeneous distribution of the Fe3O4 nanoparticles deposited on the MWCNTs. The Fe3O4 nanoparticles had diameters in the range of 4.2–10.0nm. They displayed good superparamagnetism at room temperature and their magnetization was influenced by the reaction conditions. They were used as a Fenton-like catalyst to decompose Acid Orange II and displayed a higher activity than nanometer-size Fe3O4.

One-pot reaction to synthesize superparamagnetic iron oxide nanoparticles by adding phenol as reducing agent and stabilizer

An improved thermal decomposition method was used to directly prepare water-soluble Fe3O4 magnetic nanoparticles (MNPs) with relatively higher quality via reductive decomposition of ferric acetylacetonate [Fe(acac)3], in the presence of benzyl ether and phenol, in which inexpensive phenol acted as reducing agent and stabilizer, produce the semi phenol-benzoquinone coated on the Fe3O4 and make the Fe3O4·MNPs water-soluble and the colloidal solution stable. By changing the molar ratio of phenol to Fe(acac)3 and reaction time, the size of Fe3O4·MNPs could be varied from 19.3 ± 4.4 nm to 9.7 ± 1.5 nm, with the saturation magnetizations in the range of 51.3–62.9 emu/g.

In situ preparation and magnetic properties of Fe3O4/wood composite

A Fe3O4/wood composite, a magnetic material, was prepared by in situ chemosynthesis at room temperature. X-ray diffraction (XRD), vibrating sample magnetometry (VSM) and Fourier transform infrared (FTIR) spectroscopy were applied to characterise the resulting products. The XRD results show that the average grain size of Fe3O4 was ∼14 nm. The VSM shows that the composites have saturation magnetisation Ms values from 4·7 to 25·3 emu g−1 with the increase in weight per cent gains of the wood for the composites, but the coercive forces Hc are invariable, which is different from the magnetic materials reported before. It may be due to the fact that the interaction between wood and Fe3O4 becomes stronger when less Fe3O4 particles are introduced in the composition, and this also changes the surface anisotropy Ks of the magnetism. Structural characterisation by FTIR proves the interaction between Fe3O4 particles and the wood matrix, and it also illustrates that this interaction influences the coercive force of the composite.

IRON OXIDES FROM ELECTROFILTER ASH FOR WATER TREATMENT (ARSENIC REMOVAL)

Arsenic (As)-contaminated drinking water is a major problem around the world. The removal efficiency depends strongly on the size of Fe3O4 sorbents.Fe3O4 prepared in laboratory is more efficient in the removal of As and is also more easily recovered from column of magnetic separator than the commercial materials. This would be beneficial in a water treatment system because the As-contaminated Fe3O4 could be flushed from the column permitting reuse of the separator system. The dispersed Fe3O4 nanocrystals can be removed from the solution through interactions with a magnetic column. The 20 nm commercially made nanocrystals were permanently retained in the column and could not be recovered, while the laboratory prepared nanocrystals were able to be recovered when the magnetic field was turned off.

Novel Synthesis of Silica‐Coated Ferrite Nanoparticles Prepared Using Water‐in‐Oil Microemulsion

Ferrite nanoparticles (magnetite (Fe3O4) and cobalt‐ferrite (CoxFe3−xO4)) coated with silica (SiO2) were prepared using water‐in‐oil microemulsion of a polyoxyethylen(15)cetylether/cyclohexene system. Observation via transmission electron microscopy revealed that the ferrite nanoparticles were located nearly at the center of spherical SiO2 particles. The sizes of Fe3O4 and CoxFe3−xO4 nanoparticles were in the range of 8–12 nm and 10–14 nm, respectively, and the thickness of the SiO2 layer was ∼14.0 nm. The solid solution of cobalt ions into Fe3O4 to form CoxFe3−xO4 nanoparticles led to an increase in the coercivity of the SiO2‐coated ferrite nanoparticles. The coercivity increased with increasing amounts of added cobalt, obtaining a maximum value of 780 Oe around a Co/Fe ratio of 0.3–0.4.