Relevant bibliographies by topics / Maghemite Synthesis / Journal articles

Journal articles on the topic 'Maghemite Synthesis'

To see the other types of publications on this topic, follow the link: Maghemite Synthesis.
Author: Grafiati
Published: 10 December 2022
Last updated: 29 January 2023

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Maghemite Synthesis.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

El-Subruiti, G. M., A. S. Eltaweil, and S. A. Sallam. "Synthesis of Active MFe2O4/γ-Fe2O3 Nanocomposites (Metal = Ni or Co) for Reduction of Nitro-Containing Pollutants and Methyl Orange Degradation." Nano 14, no. 10 (October 2019): 1950125. http://dx.doi.org/10.1142/s179329201950125x.

Full text
Abstract:
Metal-ferrite/maghemite nanocomposites (NiFe2O4/***[Formula: see text]-Fe2O3 and CoFe2O4/[Formula: see text]-Fe2O[Formula: see text] were synthesized via doping maghemite with metal salt (NiCl2 or CoCl[Formula: see text] followed by reduction of metal ions using NaBH4. The synthesized metal-ferrite/maghemite nanocomposites were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Fourier transform infrared (FTIR) and the amounts of the dopant-metal (Ni/Co) were determined using ICP-OES technique. Results showed that this synthetic route produced nanocomposites with highly active ferrite phases MFe2O4. The synthesized nanocomposites exhibited exceptional catalytic activities for the reduction of 4-nitrophenol and 2-nitroaniline as well as the catalytic degradation of methyl orange. Specific activity parameter of NiFe2O4/[Formula: see text]-Fe2O3 and CoFe2O4/[Formula: see text]-Fe2O3 toward reduction of 4-NP reached 993.9 and 929.8[Formula: see text]s[Formula: see text][Formula: see text]g[Formula: see text], respectively. These high values of specific activities are higher than most reported metal-ferrite composites prepared via traditional co-precipitation methods. Besides, strong magnetic properties of the prepared metal-ferrite/maghemites facilitates easy separation process for several reuses.
APA, Harvard, Vancouver, ISO, and other styles
2

Sinha, Arvind, Jui Chakraborty, P. A. Joy, and P. Ramachandrarao. "Magnetic field–induced biomimetic synthesis of superparamagnetic poly (vinyl alcohol)–maghemite composite." Journal of Materials Research 19, no. 6 (June 2004): 1676–81. http://dx.doi.org/10.1557/jmr.2004.0246.

Full text
Abstract:
Poly (vinyl alcohol)–mediated synthesis of monodisperse, self-assembled, superparamagnetic maghemite particles was carried out through a magnetic field–induced biomimetic route. Modifying the kinetics of precipitation, the magnetic field promoted the nucleation of the maghemite phase over magnetite and also induced a self-assembly–assisted shape anisotropy during the precipitation of the particles in the polymer matrix.
APA, Harvard, Vancouver, ISO, and other styles
3

Ikhaddalene, Soumia, Fatima Zibouche, Alain Ponton, Amar Irekti, and Florent Carn. "Synthesis and Rheological Properties of Magnetic Chitosan Hydrogel." Periodica Polytechnica Chemical Engineering 65, no. 3 (May 6, 2021): 378–88. http://dx.doi.org/10.3311/ppch.17148.

Full text
Abstract:
The aim of the present work is first to synthesis a magnetic chitosan hydrogel (chitosan ferrogel) using the blending method and second to study it rheological behavior. Magnetic components ( maghemite particles γ-Fe2O3 ) were synthesized via a simple chemical co-precipitation route also called Massart's procedure. Before being dispersed in chitosan network, γ-Fe2O3 particles were covered with a cationic polyelectrolyte (Polydiallyldimethylammonium chloride; PDADMAC) and the exact quantity required to cover the entire surface of maghemite particles was determined by Electrophoretic mobility. The successful functionalization of maghemite particles was confirmed by zeta potential measurement. The prepared ferrogel was gelified using glyoxal as crosslinking agent. The effect of continuous magnetic field on rheological properties of the elaborated ferrogel was studied, under controlled temperature before and after the gelation process, using a rotating rheometer fitted with a new magneto-rheological cell. Moreover the influence of iron oxide content on the gelation time of magnetic hydrogel was studied by comparing two ferrogels with different maghemite particles content. Flow and viscoelastic measurements showed that applying magnetic field facilitates the formation of a new structure (column-like arrangements), which was confirmed by in situ optical microscopic observation. Kinetic study was investigated by mechanical spectroscopy and demonstrates that the gelation time depends on both iron oxides content and magnetic field.
APA, Harvard, Vancouver, ISO, and other styles
4

Kartswnakis, Ioannis, N. Papadopoulos, P. Tserotas, and P. Švec. "Low-Temperature Synthesis of Maghemite Nanoparticles." Key Engineering Materials 543 (March 2013): 468–71. http://dx.doi.org/10.4028/www.scientific.net/kem.543.468.

Full text
Abstract:
Recently, the preparation of magnetic iron oxide nanoparticles has been thoroughly studied due to their unique electric and magnetic properties. Magnetic nanoparticles find uses in a wide range of applications, from data storage and sensors to medical imaging and cancer treatment. Herein, we report a fast and economic chemical procedure for the growth of monodispersed maghemite nanoparticles (NPs) from iron pentacarbonyl Fe (CO)5. The reaction takes place in a closed vessel where the oxidation strength of dimethylsulfoxide (DMSO) is limited by the reductive strength of liberated carbon monoxide from the initial complex. DMSO strips metallic Fe from the intermediate organometallic precursors (e.g. Fe2(CO)9, Fe3(CO)12), which form at temperatures above 100 °C, while at the same time oxidizes it in a controlled manner to the desired magnetic phase at temperatures as low as 130 OC, without the need for the classical refluxing step. Oleic acid is also used as a surfactant, thus maintaining a narrow size distribution of NPs. Another advantage of the synthetic route is the short reaction time (30 min).
APA, Harvard, Vancouver, ISO, and other styles
5

Drofenik, Miha, Gregor Ferk, Matjaž Kristl, and Darko Makovec. "Synthesis and characterization of maghemite nanosheets." Materials Letters 65, no. 3 (February 2011): 439–41. http://dx.doi.org/10.1016/j.matlet.2010.11.009.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Bee, A., R. Massart, and S. Neveu. "Synthesis of very fine maghemite particles." Journal of Magnetism and Magnetic Materials 149, no. 1-2 (August 1995): 6–9. http://dx.doi.org/10.1016/0304-8853(95)00317-7.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Kotsyubynsky, V., A. Hrubiak, V. Moklyak, L. Mohnatska, and S. Fedorchenko. "Synthesis and Properties of Mesoporous Maghemite." Acta Physica Polonica A 133, no. 4 (April 2018): 1035–37. http://dx.doi.org/10.12693/aphyspola.133.1035.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Sinha, Arvind, Suprabha Nayar, G. V. S. Murthy, P. A. Joy, V. Rao, and P. Ramachandrarao. "Biomimetic synthesis of superparamagnetic iron oxide particles in proteins." Journal of Materials Research 18, no. 6 (June 2003): 1309–13. http://dx.doi.org/10.1557/jmr.2003.0180.

Full text
Abstract:
Matrix-mediated in situ synthesis of monodispersed magnetite and maghemite nanoparticles (2–16 nm) was carried out using the cavities present in gels of globular proteins such as egg white and bovine serum albumin. Under stringent conditions, spatial-charge-distribution-assisted molecular recognition of proteins for inorganic ions led to the site- and polymorph-specific synthesis of superparamagnetic iron oxide particles. A transformation from magnetite to maghemite as a nucleating phase could be observed by partially denaturing the egg white protein, signifying the delicate role of quaternary structure of proteins under different reaction conditions, in determining the size and shape of the polymorph.
APA, Harvard, Vancouver, ISO, and other styles
9

Nurdin, Irwan, Mohd Rafie Johan, Iskandar Idris Yaacob, and Bee Chin Ang. "Effect of Nitric Acid Concentrations on Synthesis and Stability of Maghemite Nanoparticles Suspension." Scientific World Journal 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/589479.

Full text
Abstract:
Maghemite(γ-Fe2O3)nanoparticles have been synthesized using a chemical coprecipitation method at different nitric acid concentrations as an oxidizing agent. Characterization of all samples performed by several techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), alternating gradient magnetometry (AGM), thermogravimetric analysis (TGA), dynamic light scattering (DLS), and zeta potential. The XRD patterns confirmed that the particles were maghemite. The crystallite size of all samples decreases with the increasing concentration of nitric acid. TEM observation showed that the particles have spherical morphology with narrow particle size distribution. The particles showed superparamagnetic behavior with decreased magnetization values at the increasing concentration of nitric acid. TGA measurement showed that the stability temperature decreases with the increasing concentration of nitric acid. DLS measurement showed that the hydrodynamic particle sizes decrease with the increasing concentration of nitric acid. Zeta potential values show a decrease with the increasing concentration of nitric acid. The increasing concentration of nitric acid in synthesis of maghemite nanoparticles produced smaller size particles, lower magnetization, better thermal stability, and more stable maghemite nanoparticles suspension.
APA, Harvard, Vancouver, ISO, and other styles
10

Trushkina, Yulia, Cheuk-Wai Tai, and German Salazar-Alvarez. "Fabrication of Maghemite Nanoparticles with High Surface Area." Nanomaterials 9, no. 7 (July 12, 2019): 1004. http://dx.doi.org/10.3390/nano9071004.

Full text
Abstract:
Maghemite nanoparticles with high surface area were obtained from the dehydroxylation of lepidocrocite prismatic nanoparticles. The synthesis pathway from the precursor to the porous maghemite nanoparticles is inexpensive, simple and gives high surface area values for both lepidocrocite and maghemite. The obtained maghemite nanoparticles contained intraparticle and interparticle pores with a surface area ca. 30 × 103 m2/mol, with pore volumes in the order of 70 cm3/mol. Both the surface area and pore volume depended on the heating rate and annealing temperature, with the highest value near the transformation temperature (180–250 °C). Following the transformation, in situ X-ray diffraction (XRD) allowed us to observe the temporal decoupling of the decomposition of lepidocrocite and the growth of maghemite. The combination of high-angle annular dark-field imaging using scanning transmission electron microscopy (HAADF-STEM) and surface adsorption isotherms is a powerful approach for the characterization of nanomaterials with high surface area and porosity.
APA, Harvard, Vancouver, ISO, and other styles
11

Leone, V. O., M. C. Pereira, S. F. Aquino, L. C. A. Oliveira, S. Correa, T. C. Ramalho, L. V. A. Gurgel, and A. C. Silva. "Adsorption of diclofenac on a magnetic adsorbent based on maghemite: experimental and theoretical studies." New Journal of Chemistry 42, no. 1 (2018): 437–49. http://dx.doi.org/10.1039/c7nj03214e.

Full text
APA, Harvard, Vancouver, ISO, and other styles
12

Vollath, D., D. V. Szabó, R. D. Taylor, and J. O. Willis. "Synthesis and Magnetic Properties of Nanostructured Maghemite." Journal of Materials Research 12, no. 8 (August 1997): 2175–82. http://dx.doi.org/10.1557/jmr.1997.0291.

Full text
Abstract:
Nanocrystalline maghemite, γ–Fe2O3, can be synthesized in a microwave plasma using FeCl3 or Fe3(CO)12 as the precursor. Electron microscopy revealed particle sizes in the range of 5 to 10 nm. In general, this material is superparamagnetic. The magnetic properties are strongly dependent on the precursor. In both cases the production process leads to a highly disordered material with the consequence of a low magnetization. The assumption of a disordered structure is also supported by electron energy loss (EEL) and Mössbauer spectroscopy. The structure of this material shows a nearly identical number of cations on tetrahedral and octahedral lattice sites.
APA, Harvard, Vancouver, ISO, and other styles
13

Tadic, Marin, and Nada Citakovic. "Mechanochemical synthesis and magnetic properties of maghemite." Vojnotehnicki glasnik 59, no. 3 (2011): 91–105. http://dx.doi.org/10.5937/vojtehg1103091t.

Full text
APA, Harvard, Vancouver, ISO, and other styles
14

Tural, Bilsen, Macit Özenbaş, Selçuk Atalay, and Mürvet Volkan. "Rapid Synthesis and Characterization of Maghemite Nanoparticles." Journal of Nanoscience and Nanotechnology 8, no. 2 (February 1, 2008): 861–66. http://dx.doi.org/10.1166/jnn.2008.b269.

Full text
Abstract:
Fe2O3–SiO2 nanocomposites were prepared by a sol–gel method using various evaporation surface to volume (S/V) ratios ranging from 0.03 to 0.2. The Fe2O3–SiO2 sols were gelated at various temperatures ranging from 50 °C to 70 °C, and subsequently they were calcined in air at 400 °C for 4 hours. The structure and the magnetic properties of the prepared Fe2O3–SiO2 nanocomposites were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), differential thermal analysis (DTA), and vibrating sample magnetometer (VSM) measurements. The gelation temperature of the Fe2O3–SiO2 sols influenced strongly the particle size and crystallinity of the maghemite nanoparticles. It was observed that the particle size of maghemite nanoparticles increased with the increasing of the gelation temperature of the sols, which may be due to the agglomeration of the maghemite particles at elevated temperatures inside the microporosity of the silica matrix during the gelation process, and the subsequent calcination of these gels at 400 °C resulted in the formation of large size iron oxide particles. Magnetization studies at temperatures of 10, 195, and 300 K showed superparamagnetic behavior for all the nanocomposites prepared using the evaporation surface to volume ratio (S/V) of 0.1, 0.2, 0.09, and 0.08. The saturation magnetization, Ms, values measured at 10K were 5.5, 8.5, and 9.5 emu/g, for the samples gelated at 50, 60, and 70 °C, respectively. At the gelation temperature of 70 °C, γ-Fe2O3 crystalline superparamagnetic nanoparticles with the particle size of 9±2 nm were formed in 12 hours for the samples prepared at the S/V ratio of 0.2.
APA, Harvard, Vancouver, ISO, and other styles
15

Drofenik, M., M. Kristl, D. Makovec, Z. Jagličić, and D. Hanžel. "Sonochemically assisted synthesis of zinc-doped maghemite." Ultrasonics Sonochemistry 15, no. 5 (July 2008): 791–98. http://dx.doi.org/10.1016/j.ultsonch.2007.10.002.

Full text
APA, Harvard, Vancouver, ISO, and other styles
16

Yao, Juan, Junying Chen, Kui Shen, and Yingwei Li. "Phase-controllable synthesis of MOF-templated maghemite–carbonaceous composites for efficient photocatalytic hydrogen production." Journal of Materials Chemistry A 6, no. 8 (2018): 3571–82. http://dx.doi.org/10.1039/c7ta10284d.

Full text
APA, Harvard, Vancouver, ISO, and other styles
17

Khan, Umar Saeed, Abdul Manan, Nasrullah Khan, Amir Mahmood, and Abdur Rahim. "Transformation mechanism of magnetite nanoparticles." Materials Science-Poland 33, no. 2 (June 1, 2015): 278–85. http://dx.doi.org/10.1515/msp-2015-0037.

Full text
Abstract:
AbstractA simple oxidation synthesis route was developed for producing magnetite nanoparticles with controlled size and morphology. Investigation of oxidation process of the produced magnetite nanoparticles (NP) was performed after synthesis under different temperatures. The phase transformation of synthetic magnetite nanoparticles into maghemite and, henceforth, to hematite nanoparticles at different temperatures under dry oxidation has been studied. The natural magnetite particles were directly transformed to hematite particles at comparatively lower temperature, thus, maghemite phase was bypassed. The phase structures, morphologies and particle sizes of the produced magnetic nanoparticles have been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDX) and BET surface area analysis.
APA, Harvard, Vancouver, ISO, and other styles
18

Wetegrove, Marcel, Kerstin Witte, Wiktor Bodnar, Dan-Eric Pfahl, Armin Springer, Norbert Schell, Fritz Westphal, and Eberhard Burkel. "Formation of maghemite nanostructures in polyol: tuning the particle size via the precursor stoichiometry." CrystEngComm 21, no. 12 (2019): 1956–66. http://dx.doi.org/10.1039/c8ce02115e.

Full text
APA, Harvard, Vancouver, ISO, and other styles
19

Cheng, Zuolian, Annie Lai Kuan Tan, Yong Tao, Dan Shan, Kok Eng Ting, and Xi Jiang Yin. "Synthesis and Characterization of Iron Oxide Nanoparticles and Applications in the Removal of Heavy Metals from Industrial Wastewater." International Journal of Photoenergy 2012 (2012): 1–5. http://dx.doi.org/10.1155/2012/608298.

Full text
Abstract:
This study investigated the applicability of maghemite (γ-Fe2O3) nanoparticles for the selective removal of toxic heavy metals from electroplating wastewater. The maghemite nanoparticles of 60 nm were synthesized using a coprecipitation method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX). Batch experiments were carried out for the removal of Pb2+ions from aqueous solutions by maghemite nanoparticles. The effects of contact time, initial concentration of Pb2+ions, solution pH, and salinity on the amount of Pb2+removed were investigated. The adsorption process was found to be highly pH dependent, which made the nanoparticles selectively adsorb this metal from wastewater. The adsorption of Pb2+reached equilibrium rapidly within 15 min and the adsorption data were well fitted with the Langmuir isotherm.
APA, Harvard, Vancouver, ISO, and other styles
20

Theerdhala, Sriharsha, Devendra Alhat, Satish Vitta, and D. Bahadur. "Synthesis of Shape Controlled Ferrite Nanoparticles by Sonochemical Technique." Journal of Nanoscience and Nanotechnology 8, no. 8 (August 1, 2008): 4268–72. http://dx.doi.org/10.1166/jnn.2008.an21.

Full text
Abstract:
Synthesis of magnetic iron oxides/ferrites in the nano scale by sonochemical synthesis has become prominent recently. This technique facilitates the synthesis of magnetic particles in the nano scale attributed to the hotspot mechanism arising due to acoustic cavitation induced chemical reaction. Generally volatile organometallic precursor compounds favoring the formation of fully amorphous particles have been used to synthesize various nano magnetic materials. We report here the synthesis of ultrafine, <10 nm magnetic iron oxide nanoparticles by sonochemical technique starting with a non-volatile precursor iron salt such as iron citrate which seems to favor the formation of semi crystalline/crystalline particles as the reaction takes place either in the interfacial region or in the bulk solution. Mono dispersed, ultra fine, ∼4 nm spherical shaped magnetic maghemite particles having a saturation magnetization of 58.2 emu/g and coercivity of 118 Oe were obtained at low values of pH, 10 while higher pH, 11–13 favored the formation of elongated, cylindrical, acicular particles with a reduced magnetization. The coercivity was also found to decrease with increasing pH, with it being 118 Oe at pH 10 and 3 Oe at pH 13. When the ultrasound amplitude/intensity was low, 38% heat treatment of the samples at 300 °C (at pH 10) was required to make them crystalline, while application of high intensity ultrasound, 50% amplitude served as a single step mechanism for obtaining crystalline maghemite particles. The maghemite particles obtained at a pH of 10 could find applications in information storage media.
APA, Harvard, Vancouver, ISO, and other styles
21

NKUTHA, C. S., N. D. SHOOTO, and E. B. NAIDOO. "Coral Limestone Modified by Magnetite and Maghemite Nanocomposites for Sequestration of Lead(II) and Chromium(VI) Ions from Aqueous Solution." Asian Journal of Chemistry 33, no. 4 (March 20, 2021): 712–26. http://dx.doi.org/10.14233/ajchem.2021.23027.

Full text
Abstract:
In present work, a one pot synthesis of magnetic nanocomposites was synthesized by using co-precipitation method in air atmosphere. The synthesis of magnetite and maghemite supported on biogenic coral limestone was done by varying the ratio of Fe(II)/Fe(III) in solution to obtain the two phases of iron oxide and capping with sucrose in air atmosphere. The nanocomposites were characterized by FTIR, where the results showed a distinct peak for Fe-O, while UV/vis showed an absorption in the visible region which is typical of iron oxide. Photoluminescence results showed that the nanocomposites were both red shifted for magnetite-PCLS (PCLS = pristine coral limestone) and magnetite-CCLS (CCLS = calcined coral limestone); while a blue shift and red shift was observed for the maghemite- PCLS and maghemite-CCLS. From the SEM a deviation of sphericity of the nanocomposites, with maghemite having an uneven distribution was observed. Equilibrium was reached within 60 min, of which maghemite showed higher metal uptake. The kinetic data fit PSOM better as compared to PFOM, this means that adsorption was due to the charge density on the surface of the nanocomposites. The good fit for intraparticle diffusion (IPD) also suggested that adsorption was also observed due to mass transfer, it was observed that the rate limiting step was due to surface adsorption. This was in good correlation with the better fit of PSOM. The mechanism of adsorption was found to be better explained by physisorption and the surface was heterogeneous whereby multilayer adsorption was possible. The data was also subjected to Dubinin-Radushkevich isotherm, which suggests that the uptake of the pollutants was due to physisorption. The adsorption process was spontaneous and favourable which is supported by the negative values of Gibb’s free energy for the system.
APA, Harvard, Vancouver, ISO, and other styles
22

Bhagwat, Shrikant, Hema Singh, Anjali Athawale, Beatrice Hannoyer, Samuel Jouen, Benoit Lefez, Darshan Kundaliya, Renu Pasricha, Shailaja Kulkarni, and Satishchandra Ogale. "Low Temperature Synthesis of Magnetite and Maghemite Nanoparticles." Journal of Nanoscience and Nanotechnology 7, no. 12 (December 1, 2007): 4294–302. http://dx.doi.org/10.1166/jnn.2007.873.

Full text
Abstract:
We report on the synthesis of iron oxide nanoparticles below 100 °C by a simple chemical protocol. The uniqueness of the method lies in the use of Ferrous ammonium sulphate (in conjugation with FeCl3) which helps maintain the stability of Fe2+ state in the reaction sequence thereby controlling the phase formation. Hexamine was added as the stabilizer. The nanoparticles synthesized at three different temperatures viz, 5°, 27°, and 95 °C are characterized by several techniques. Generally, when a mixture of Fe3+ and Fe2+ is added to sodium hydroxide, α-Fe2O3 (the anti-ferromagnetic phase) is formed after the dehydration process of the hydroxide. In our case however, the phases formed at all the three temperatures were found to be ferro (ferri) magnetic, implying modification of the formation chemistry due to the specifics of our method. The nanoparticles synthesized at the lowest temperature exhibit magnetite phase, while increase in growth temperature to 95 °C leads to the maghemite phase.
APA, Harvard, Vancouver, ISO, and other styles
23

Xue, De-Sheng, Li-Ying Zhang, and Fa-Shen Li. "Synthesis and Mössbauer Study of Maghemite Nanowire Arrays." Hyperfine Interactions 156/157, no. 1-4 (2004): 41–46. http://dx.doi.org/10.1023/b:hype.0000043214.36740.70.

Full text
APA, Harvard, Vancouver, ISO, and other styles
24

Woo, Kyoungja, and Ho Jin Lee. "Synthesis and magnetism of hematite and maghemite nanoparticles." Journal of Magnetism and Magnetic Materials 272-276 (May 2004): E1155—E1156. http://dx.doi.org/10.1016/j.jmmm.2003.12.201.

Full text
APA, Harvard, Vancouver, ISO, and other styles
25

Sun, Yong-kang, Ming Ma, Yu Zhang, and Ning Gu. "Synthesis of nanometer-size maghemite particles from magnetite." Colloids and Surfaces A: Physicochemical and Engineering Aspects 245, no. 1-3 (September 2004): 15–19. http://dx.doi.org/10.1016/j.colsurfa.2004.05.009.

Full text
APA, Harvard, Vancouver, ISO, and other styles
26

Hrubiak, A. B., O. Yu Khyzhun, B. K. Ostafiychuk, V. V. Moklyak, Yu V. Yavorskyi, R. P. Lisovsky, L. G. Keush, and B. B. Onyskiv. "Nanostructured mesoporous g-Fe2O3: a novel photocatalyst for degradation of organic pollutants." Physics and Chemistry of Solid State 22, no. 1 (March 12, 2021): 101–9. http://dx.doi.org/10.15330/pcss.22.1.101-109.

Full text
Abstract:
The modified sol-gel synthesis technique was used to created of nanostructured maghemite (γ-Fe2O3). It has been shown that the molar concentration of the original precursors during synthesis affects on the average particle sizes, specific surface area, pore size distributions, optical and conductivity properties. The XPS metod allowed to establish features of electronic structure of the synthesized materials. Optimal conditions for the synthesis of nanostructured maghemite with mesoporous structure were selected. The mechanism of electrical conductivity formation for synthesized mesoporous materials was established. The width of the band gap is determined and its dependence on the molar concentration of precursors is established. The positive correlation between the specific surface area of γ-Fe2O3 samples and photocatalytic activity was installed - the photocatalytic activity of synthesized γ-Fe2O3 increase with growth of specific surface area of γ-Fe2O3 samples.
APA, Harvard, Vancouver, ISO, and other styles
27

Schwaminger, Sebastian P., Christopher Syhr, and Sonja Berensmeier. "Controlled Synthesis of Magnetic Iron Oxide Nanoparticles: Magnetite or Maghemite?" Crystals 10, no. 3 (March 19, 2020): 214. http://dx.doi.org/10.3390/cryst10030214.

Full text
Abstract:
Today, magnetic nanoparticles are present in multiple medical and industrial applications. We take a closer look at the synthesis of magnetic iron oxide nanoparticles through the co-precipitation of iron salts in an alkaline environment. The variation of the synthesis parameters (ion concentration, temperature, stirring rate, reaction time and dosing rate) change the structure and diameter of the nanoparticles. Magnetic iron oxide nanoparticles are characterized by X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM). Magnetic nanoparticles ranging from 5 to 16 nm in diameter were synthesized and their chemical structure was identified. Due to the evaluation of Raman spectra, TEM and XRD, the magnetite and maghemite nanoparticles can be observed and the proportion of phases and the particle size can be related to the synthesis conditions. We want to highlight the use of Raman active modes A1g of spinel structured iron oxides to determine the content of magnetite and maghemite in our samples. Magnetite nanoparticles can be derived from highly alkaline conditions even without establishing an inert atmosphere during the synthesis. The correlation between the particle properties and the various parameters of the synthesis was modelled with linear mixture models. The two models can predict the particle size and the oxidation state of the synthesized nanoparticles, respectively. The modeling of synthesis parameters not only helps to improve synthesis conditions for iron oxide nanoparticles but to understand crystallization of nanomaterials.
APA, Harvard, Vancouver, ISO, and other styles
28

Suhafri, M., and Iskandar Idris Yaacob. "Synthesis of High Aspect Ratio Iron Oxide Nanoparticles Using Water in Oil Microemulsion." Key Engineering Materials 345-346 (August 2007): 1601–4. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.1601.

Full text
Abstract:
High aspect ratios maghemite of iron oxide nanoparticles were prepared using water in oil microemulsions. A four component microemulsion system with cationic HTAB, n-butanol, noctane, and salt solution was used. Precipitations of iron oxide were initiated by mixing a microemulsion system containing Fe2+ with another microemulsion system containing OH-. The resulting particles were characterized using XRD, AGM and TEM. The XRD result showed the formation of maghemite. TEM showed that the average length of needle shaped particles increased from 28 nm up to 42 nm as the aging time was increased from 4 to 24 hours while the average diameter spherical particle remained at around 8 nm. The AGM confirmed that the particles are superparamagnetic.
APA, Harvard, Vancouver, ISO, and other styles
29

Woo, Kyoungja, and Ho Jin Lee. "Preparation of Maghemite Nanoparticles for Clinical Applications." Key Engineering Materials 277-279 (January 2005): 876–80. http://dx.doi.org/10.4028/www.scientific.net/kem.277-279.876.

Full text
Abstract:
The synthesis of nearly monodisperse, roughly spherical, and non-aggregated maghemite (g-Fe2O3) nanoparticles (average diameter = 5.5 nm, standard deviation = 0.7 nm over 100 particles) is reported. We utilized a sol-gel reaction of common ferric salt in reverse micelles and then, crystallization of the gel particles by reflux. The nanoparticles show superparamagnetic behavior and are expected to be useful for clinical applications.
APA, Harvard, Vancouver, ISO, and other styles
30

Mohd Yusoff, Ahmad Huzaifah, Midhat Nabil Ahmad Salimi, and Mohd Faizal Jamlos. "A New XRD Method to Quantitatively Distinguish Non-Stoichiometric Magnetite: Influence of Particle Size and Processing Conditions." Advanced Engineering Forum 26 (February 2018): 41–52. http://dx.doi.org/10.4028/www.scientific.net/aef.26.41.

Full text
Abstract:
Magnetite’s abilities rely on the quantitative phases present in the sample. Magnetite quality can strongly influence several physical properties, such as magnetism, catalytic performance, and Verwey transition. However, differentiation of magnetite and maghemite through the conventional X-ray diffractogram comparison are not relevant for the intermediate phases. In this study, the deviation from the ideal stoichiometric magnetite and the relative quantification of both phases were mathematically achievable through a new XRD technique. Various synthesis conditions were applied to obtain different crystallite sizes, in the range of 9 to 30 nm. Generally, the stoichiometric deviation and maghemite content would be significantly influenced by the final size, whereas system conditions (temperature of solution, agitation rate, and pH of solution) would only have minor significance. In this study, iron oxide nanoparticles prepared using the co-precipitation method was calculated to contain 100% magnetite for particles of 30.26 nm in size, while 100% maghemite was calculated for particles at 9.64 nm.
APA, Harvard, Vancouver, ISO, and other styles
31

Камзин, А. С., I. M. Obaidat, А. А. Валлиулин, В. Г. Семенов, and I. A. Al-Omari. "Мёссбауэровские исследования состава и магнитной структуры нанокомпозитов Fe-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=-/γFe-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=- типа ядро--оболочка при температура 300 и 80 K (Часть I)." Физика твердого тела 62, no. 10 (2020): 1715. http://dx.doi.org/10.21883/ftt.2020.10.49928.056.

Full text
Abstract:
The results of Mössbauer studies of the magnetic structure and composition of Fe3O4 / γ-Fe2O3 nanoparticles at temperatures of 300 and 80 K are presented. It was found that particles Fe3O4 /γ-Fe2O3 is a core / shell nanocomposite (NC) in which magnetite (Fe3O4) is a coated by shell of maghemite (γ-Fe2O3). It was shown that the thickness of the maghemite (γ-Fe2O3) shell depends on the synthesis technology. It was found that, in the Fe3O4 /γ-Fe2O3 NC, on the surface of the maghemite (γ-Fe2O3) shell, a layer whose magnetic structure differs from the structure of the inner part of the shell (γ-Fe2O3). An intermediate layer is formed between the core and the shell in a spin-glass state. The obtained data on the structure of core / shell nanocomposites open up prospects for explaining the properties of such particles, which are of great interest for applications in various fields, including biomedicine.
APA, Harvard, Vancouver, ISO, and other styles
32

Hojnik Podrepšek, Gordana, Željko Knez, and Maja Leitgeb. "Development of Chitosan Functionalized Magnetic Nanoparticles with Bioactive Compounds." Nanomaterials 10, no. 10 (September 25, 2020): 1913. http://dx.doi.org/10.3390/nano10101913.

Full text
Abstract:
In this study, magnetic maghemite nanoparticles, which belong to the group of metal oxides, were functionalized with chitosan, a non-toxic, hydrophilic, biocompatible, biodegradable biopolymer with anti-bacterial effects. This was done using different synthesis methods, and a comparison of the properties of the synthesized chitosan functionalized maghemite nanoparticles was conducted. Characterization was performed using scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). Characterizations of size distribution were performed using dynamic light scattering (DLS) measurements and laser granulometry. A chitosan functionalization layer was confirmed using potentiometric titration on variously synthesized chitosan functionalized maghemite nanoparticles, which is important for further immobilization of bioactive compounds. Furthermore, after activation of chitosan functionalized maghemite nanoparticles with glutaraldehyde (GA) or pentaethylenehexamine (PEHA), immobilization studies of enzyme cholesterol oxidase (ChOx) and horseradish peroxidase (HRP) were conducted. Factors influencing the immobilization of enzymes, such as type and concentration of activating reagent, mass ratio between carrier and enzyme, immobilization time and enzyme concentration, were investigated. Briefly, microparticles made using the chitosan suspension cross-linking process (MC2) proved to be the most suitable for obtaining the highest activity of immobilized enzyme, and nanoparticles functionalized with chitosan using the covalent binding method (MC3) could compete with MC2 for their applications.
APA, Harvard, Vancouver, ISO, and other styles
33

Ramesh, Sivarajan, Israel Felner, Yuri Koltypin, and Aharon Gedanken. "Reaction Pathways at the Iron–microspherical Silica Interface: Mechanistic Aspects of the Formation of Target Iron Oxide Phases." Journal of Materials Research 15, no. 4 (April 2000): 944–50. http://dx.doi.org/10.1557/jmr.2000.0135.

Full text
Abstract:
Oxidative hydrolysis of elemental iron nanoclusters on hydroxylated surfaces such as silica or alumina is known to be influenced by the degree of hydration of the surface. The understanding and control of this process is crucial in the synthesis of iron oxide coated silica microspheres with a desired magnetic property. The hydrolysis of iron nanoparticles followed by heat treatment in the case of a hydrated microspherical silica surface results in the formation of maghemite (γ–Fe2O3), whereas a dehydrated surface yielded hematite (α–Fe2O3) nanoparticles. The influence of adsorbed water on the formation of intermediate iron oxides/oxidehydroxides and the mechanistic aspects of their subsequent thermal dehydration iron oxide phases were investigated by thermogravimetric analysis, Fourier transform infrared, and Mössbauer spectroscopies. The reactions on both the hydrated and the dehydrated surfaces were found to proceed through the formation of an x-ray amorphous lepidocrocite [γ–FeO(OH)] intermediate and its subsequent dehydration to maghemite (γ–Fe2O3). Maghemite to hematite transformation was readily facilitated only on a dry silica surface. The retardation of the lepidocrocite →maghemite →hematite transformation in the case of a hydrated silica surface is suggested to arise from strong hydrogen-bonded interactions between the substrate silica and the adsorbed nanoparticles.
APA, Harvard, Vancouver, ISO, and other styles
34

Santoso, Uripto Trisno, Abdullah, Dwi Rasy Mujiyanti, Dahlena Ariyani, and Joyo Waskito. "Room Temperature Synthesis of Magnetite Particles by an Oil Membrane Layer-Assisted Reverse Co-Precipitation Approach." Advanced Materials Research 1162 (April 2021): 41–46. http://dx.doi.org/10.4028/www.scientific.net/amr.1162.41.

Full text
Abstract:
Reverse co-precipitation (RCP) in ambient atmosphere is one of the strategies to produce magnetite nanoparticles in a rapid, simple, and cost-effective synthesis route without applying temperature surfactants or inert gases. However, RCP of ferrous/ferric blended salt in sodium hydroxide (NaOH) solution in an oxidizing medium produced of maghemite as a dominant phase rather than magnetite because of the oxidation of Fe2+ to Fe3+ happened. Based on this background, an oil membrane layer-assisted reverse co-precipitation approach has been examined to synthesis of magnetite in ambient atmosphere at room temperature. The result showed that although addition of benzene as an oil membrane layer was effective to prevent oxidation of magnetite to maghemite, but the magnetite particle size for the samples from the oil membrane layer-assisted reverse co-precipitation method was much larger than that from a reverse co-precipitation method without addition of oil membrane layer.
APA, Harvard, Vancouver, ISO, and other styles
35

Matutes-Aquino, José Andrés, Perla E. García, O. Ayala Valenzuela, and S. García García. "Synthesis and Magnetic Properties of Submicronic Particles of Maghemite." Materials Science Forum 302-303 (January 1999): 469–73. http://dx.doi.org/10.4028/www.scientific.net/msf.302-303.469.

Full text
APA, Harvard, Vancouver, ISO, and other styles
36

Cappelletti, Ariel L., Julieta I. Paez, and Miriam C. Strumia. "Synthesis and characterization of thermo-sensitive magnetic maghemite nanoparticles." Arkivoc 2011, no. 7 (May 24, 2011): 426–38. http://dx.doi.org/10.3998/ark.5550190.0012.735.

Full text
APA, Harvard, Vancouver, ISO, and other styles
37

Nurdin, I., M. R. Johan, I. I. Yaacob, B. C. Ang, and A. Andriyana. "Synthesis, characterisation and stability of superparamagnetic maghemite nanoparticle suspension." Materials Research Innovations 18, sup6 (December 5, 2014): S6–200—S6–203. http://dx.doi.org/10.1179/1432891714z.0000000001017.

Full text
APA, Harvard, Vancouver, ISO, and other styles
38

Chougale, U. M., and V. J. Fulari. "Facile synthesis of maghemite nanoflakes arrays for supercapacitor application." Materials Science in Semiconductor Processing 27 (November 2014): 682–88. http://dx.doi.org/10.1016/j.mssp.2014.08.015.

Full text
APA, Harvard, Vancouver, ISO, and other styles
39

Seraj, Somaye, Behruz Mirzayi, and Ali Nematollahzadeh. "Superparamagnetic maghemite/polyrhodanine core/shell nanoparticles: Synthesis and characterization." Advanced Powder Technology 25, no. 5 (September 2014): 1520–26. http://dx.doi.org/10.1016/j.apt.2014.04.008.

Full text
APA, Harvard, Vancouver, ISO, and other styles
40

Teng, Xiaowei, Donald Black, Neil J. Watkins, Yongli Gao, and Hong Yang. "Platinum-Maghemite Core−Shell Nanoparticles Using a Sequential Synthesis." Nano Letters 3, no. 2 (February 2003): 261–64. http://dx.doi.org/10.1021/nl025918y.

Full text
APA, Harvard, Vancouver, ISO, and other styles
41

Vidal-Vidal, J., J. Rivas, and M. A. López-Quintela. "Synthesis of monodisperse maghemite nanoparticles by the microemulsion method." Colloids and Surfaces A: Physicochemical and Engineering Aspects 288, no. 1-3 (October 2006): 44–51. http://dx.doi.org/10.1016/j.colsurfa.2006.04.027.

Full text
APA, Harvard, Vancouver, ISO, and other styles
42

Talgatov, Eldar T., Assemgul S. Auyezkhanova, Kuralai S. Seitkalieva, Nurmukhamet Zh Tumabayev, Sandugash N. Akhmetova, and Alima K. Zharmagambetova. "Co-precipitation synthesis of mesoporous maghemite for catalysis application." Journal of Porous Materials 27, no. 3 (March 2, 2020): 919–27. http://dx.doi.org/10.1007/s10934-020-00869-1.

Full text
APA, Harvard, Vancouver, ISO, and other styles
43

Múzquiz-Ramos, E. M., V. Guerrero-Chávez, B. I. Macías-Martínez, C. M. López-Badillo, and L. A. García-Cerda. "Synthesis and characterization of maghemite nanoparticles for hyperthermia applications." Ceramics International 41, no. 1 (January 2015): 397–402. http://dx.doi.org/10.1016/j.ceramint.2014.08.083.

Full text
APA, Harvard, Vancouver, ISO, and other styles
44

Acarbas, Ozge, and Macit Ozenbas. "Preparation of Iron Oxide Nanoparticles by Microwave Synthesis and Their Characterization." Journal of Nanoscience and Nanotechnology 8, no. 2 (February 1, 2008): 655–59. http://dx.doi.org/10.1166/jnn.2008.b268.

Full text
Abstract:
In this study production of fine particle Fe2O3 via microwave processing of Fe(NO3)3·nH2O followed by low temperature annealing was reported. XRD was used to characterize the structural properties of nanoparticles. Approximate particle sizes were between 3–13 nm according to Scherrer's equation. Single point BET measurement results also show that samples have large surface area and they are nanometer sized particles. TEM study was conducted to examine the structure of the nanoparticles. TEM figure is in good agreement with the results obtained from Scherrer's equation using XRD spectra. In order to characterize the magnetic properties of the nanoparticles VSM (Vibrating Sample Magnetometer) was used. From these results it can be concluded that the sample containing only maghemite phase exhibits superparamagnetic behaviour, on the other hand sample containing both hematite and maghemite phases shows paramagnetic behaviour above 300 K, superparamagnetic behavior at lower temperatures.
APA, Harvard, Vancouver, ISO, and other styles
45

Rehman, Yaser, Zhenxiang Cheng, Xiaolin Wang, Xu-Feng Huang, and Konstantin Konstantinov. "Theranostic two-dimensional superparamagnetic maghemite quantum structures for ROS-mediated cancer therapy." Journal of Materials Chemistry B 9, no. 29 (2021): 5805–17. http://dx.doi.org/10.1039/d1tb01036k.

Full text
Abstract:
In this work, size- and shape-controlled two-dimensional (2D) superparamagnetic maghemite (γ-Fe2O3) quantum flakes (MQFs) with high surface area and mesoporosity were prepared by facile hydrothermal synthesis for biological applications.
APA, Harvard, Vancouver, ISO, and other styles
46

Metaxa, E. D., K. Berkesi, D. Musmarra, Athanasios G. Mamalis, and Evangelos Hristoforou. "Synthesis of Superparamagnetic Nanoparticles for Desalination Purposes." Materials Science Forum 856 (May 2016): 105–15. http://dx.doi.org/10.4028/www.scientific.net/msf.856.105.

Full text
Abstract:
The aim of this study is to describe the synthetic procedure of superparamagnetic nanoparticles of magnetite and maghemite and to use the magnetic merit of thesenano-sized ferrite particles coated byorganic substances having good water solubility to desalinate saline water. The idea derives from the experimental results of research groups using magnetic particles covered by polymers to increase the efficiency of membranes in forward osmosis desalination plants. The magnetic particles can beseparatedfrom water by an external magnet field easily.As magnetic particles, Fe3O4 can be prepared in different sizes from nanoto microscale by the help of co-precipitation or thermal decomposition techniques. These superparamagnetic nanoparticles are well-promising candidates for use in desalination purposes either from own or after their fabrication with polymer molecules, such as cyclodexrins, in their original form or in a modified one in order to enhance their water solubility, according to some preliminary experimental results found by our research team but not referred here. Herein, various inexpensive synthetic routes for superparamagnetic nanoparticles of magnetite (Fe3O4) and maghemite ( -Fe2O3) are described, as well as the characterization results of the produced nanoparticles with XRD, TEM, FT-IR, RAMAN, DFT and TGA/DTG analytical techniques are also referred.
APA, Harvard, Vancouver, ISO, and other styles
47

Yu, Taekyung. "Synthesis of Water-Dispersible Maghemite Nanocrystals using 6-Aminohexanoic Acid as a Capping Agent." Korean Chemical Engineering Research 51, no. 3 (June 1, 2013): 403–6. http://dx.doi.org/10.9713/kcer.2013.51.3.403.

Full text
APA, Harvard, Vancouver, ISO, and other styles
48

Pizúrová, N., J. Buršík, T. Sojková, P. Roupcová, and O. Schneeweiss. "Magnetic properties and morphology of ultra-small iron oxide nanoparticles." Journal of Physics: Conference Series 2315, no. 1 (July 1, 2022): 012023. http://dx.doi.org/10.1088/1742-6596/2315/1/012023.

Full text
Abstract:
Abstract Maghemite nanoparticles prepared with the modified synthesis method published by Sun et al. 2004 and followed by filtering to extract a sample of the smallest nanoparticle size were investigated. The 2-5 nm nanoparticles of monocrystalline and multi-twinned morphology without surface shells were observed. Superparamagnetic behavior was detected above the temperature of 40 K. An exchange bias loop shift of ~ 2 mT at 3 K after cooling with an external field of 3 T suggested a low influence of the surface spin disorder effect. Mössbauer spectroscopy confirmed the two phases with different blocking temperatures, the maghemite phase as well as a second one likely originating from the disordered surface component.
APA, Harvard, Vancouver, ISO, and other styles
49

Kotsyubynsky, Volodymyr, Bogdan Ostafiychuk, Volodymyr Moklyak, and Andrii Hrubiak. "Synthesis, Characterization and Electrochemical Properties of Mesoporous Maghemite γ-Fe2O3." Solid State Phenomena 230 (June 2015): 120–26. http://dx.doi.org/10.4028/www.scientific.net/ssp.230.120.

Full text
Abstract:
Mesoporous maghemite γ-Fe2O3 was obtained by thermal decomposition of iron citrate xerogel hydrate. The influence of precursor molar concentration and calcination temperature on the material phase composition, morphology, crystalline and magnetic microstructure, surface condition and optical properties was studied. The model of mesoporous γ-Fe2O3 formation is proposed. Obtained maghemite was tested as cathode material for lithium power sources. Increase of lithium power sources specific capacity and energy with the samples specific surface area enlarging is determined. Two kinetic processes are observed during discharge processes: lithium accumulation at the cathode material/electrolyte interface and diffusion of lithium ions into the material crystal structure. The diffusion coefficients of lithium in the cathode material on the different stages of discharge process are calculated.
APA, Harvard, Vancouver, ISO, and other styles
50

Malik, Vikash, Antara Pal, Olivier Pravaz, Jérôme J. Crassous, Simon Granville, Bernard Grobety, Ann M. Hirt, Hervé Dietsch, and Peter Schurtenberger. "Hybrid magnetic iron oxide nanoparticles with tunable field-directed self-assembly." Nanoscale 9, no. 38 (2017): 14405–13. http://dx.doi.org/10.1039/c7nr04518b.

Full text
Abstract:
We describe the synthesis of hybrid magnetic ellipsoidal nanoparticles that consist of a mixture of two different iron oxide phases, hematite (α-Fe2O3) and maghemite (γ-Fe2O3), and characterize their magnetic field-driven self-assembly.
APA, Harvard, Vancouver, ISO, and other styles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography