Magnetic behavior of nanocrystalline MnCo2O4 spinels

Borges, F.M.M.; Melo, D.M.A.; Câmara, M.S.A.; Martinelli, Antônio Eduardo; Soares, J.M.; Araújo, J.H. de; Cabral, Fernando A.

doi:10.1016/j.jmmm.2005.09.017

Cited by 54 publications

(20 citation statements)

References 12 publications

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“…The saturation magnetization ( M s) values for Fe 3 O 4 , Fe 3 O 4 @C and Fe 3 O 4 @C/MnCo 2 O 4 nanocomposites were 62.5, 23.6 and 14.5 emu g −1 , respectively. Due to the existence of nonmagnetic carbon and extremely weak ferromagnetic MnCo 2 O 4 in the total mass, the M s values for Fe 3 O 4 @C and Fe 3 O 4 @C/MnCo 2 O 4 are smaller than that for the Fe 3 O 4 samples. High M s of Fe 3 O 4 @C/MnCo 2 O 4 would enable good magnetic separation of the nanocomposites using an external magnet.…”

Section: Resultsmentioning

confidence: 91%

Activation of peroxymonosulfate with magnetic and recyclable Fe₃ O₄ @C/MnCo₂ O₄ nanocomposites for the decolorization of Acid Orange II

Liu

Xiong³

et al. 2016

J. Chem. Technol. Biotechnol

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BACKGROUND Synthetic dyes are present in the wastewater from many industrial processes and they cause serious problems to human and aquatic life. The development of a novel and effective peroxymonosulfate (PMS) activator is proposed to eliminate dyes pollution. A new magnetic nanocomposite, Fe3O4@C/MnCo2O4, was prepared and characterized. The activity of Fe3O4@C/MnCo2O4 as heterogeneous catalyst for PMS activation was evaluated by the decolorization of Acid Orange II (AO II). RESULTS With a ‘Fe3O4@C/MnCo2O4 + PMS’ system, the dye solution could be nearly completely decolorized in about 25 min over a wide pH range (pH 4.1−8.1), and 98% removal could be achieved in 15 min without pH adjustment (pH = 6.38). The influence of solution pH, dosage of catalyst and PMS, reaction temperature, and PMS activation mechanism were studied. It was found that sulfate radicals were the primary species responsible for the oxidation of AO II. The catalyst was magnetically separable and displayed good stability and reusability, giving six cycles of use without deterioration in its performance. CONCLUSION This study demonstrated the simple recycling and high activity of Fe3O4@C/MnCo2O4 composite in PMS activation for the decolorization of AO II solution. It provides a promising way for the decontamination of organic pollutants. © 2016 Society of Chemical Industry

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Section: Resultsmentioning

confidence: 91%

Activation of peroxymonosulfate with magnetic and recyclable Fe₃ O₄ @C/MnCo₂ O₄ nanocomposites for the decolorization of Acid Orange II

Liu

Xiong³

et al. 2016

J. Chem. Technol. Biotechnol

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“…Spinel type oxides from transition metals, particularly the manganesecobalt oxide family, are interesting systems because of their potential for a variety of applications in the conversion of energy 1,2 . Many different synthetic routes have been attempted to prepare Mn x Co 3-x O 4 oxides in powder form 3 . The commonest method for the preparation of these spinels has been the thermal decomposition of nitrate precursors at different temperatures.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Manganese- Cobalt Solid Solutions Prepared at Low Temperature

Rı́os

Lara

Serafini

et al. 2010

J. Chil. Chem. Soc.

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Two extreme compositions of the manganese-cobalt oxide system Mn x Co 3-x O 4 namely Co 3 O 4 (x = 0) and MnCo 2 O 4 (x = 1) were prepared in powder form at low temperature by thermal decomposition of nitrates in air. The synthesis was conducted at 150ºC. The oxides obtained were characterized by different techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), surface area determination using the Brunauer-Emmett-Teller (BET) method, thermogravimetric analyses (TGA) and oxidation power (OP). XRD analysis reveals that the oxides crystallize in a cubic spinel-type structure with a unit cell parameter (a o) that increases as cobalt is replaced by manganese. The MnCo 2 O 4 showed 70 m 2 g-1 and 13 nm of specific surface area and crystallite size respectively. The crystallite was bigger (20nm) when cobalt-manganese oxide is prepared as a thin film. Both compounds exhibited nanometric size. The cationic distributions proposed for both oxides on the basis of the physicochemical characterization results showed an excellent agreement with those obtained from the XRD data refinement performed using the Rietveld method.

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“…At present, the magnetic properties of the Co 3Àx Mn x O 4 system attract particular interest owing to unusual hysteresis phenomena and magnetization processes, as well as magnetic behavior of MnCo 2 O 4 in the nanocrystalline and thinfilm states [11][12][13][14]. The information on the influence of methods of synthesis and especially the temperature of synthesis on the magnetic properties of nonstoichiometric specimens MnCo 2 O 4+d is not available.…”

Section: Introductionmentioning

confidence: 99%

Magnetic behavior of MnCo2O4+δ spinel obtained by thermal decomposition of binary oxalates

Базуев

Korolyov

2008

Journal of Magnetism and Magnetic Materials

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Magnetic behavior of nanocrystalline MnCo2O4 spinels

Cited by 54 publications

References 12 publications

Activation of peroxymonosulfate with magnetic and recyclable Fe₃ O₄ @C/MnCo₂ O₄ nanocomposites for the decolorization of Acid Orange II

Activation of peroxymonosulfate with magnetic and recyclable Fe₃ O₄ @C/MnCo₂ O₄ nanocomposites for the decolorization of Acid Orange II

Synthesis and Characterization of Manganese- Cobalt Solid Solutions Prepared at Low Temperature

Magnetic behavior of MnCo2O4+δ spinel obtained by thermal decomposition of binary oxalates

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Magnetic behavior of nanocrystalline MnCo2O4 spinels

Cited by 54 publications

References 12 publications

Activation of peroxymonosulfate with magnetic and recyclable Fe3 O4 @C/MnCo2 O4 nanocomposites for the decolorization of Acid Orange II

Activation of peroxymonosulfate with magnetic and recyclable Fe3 O4 @C/MnCo2 O4 nanocomposites for the decolorization of Acid Orange II

Synthesis and Characterization of Manganese- Cobalt Solid Solutions Prepared at Low Temperature

Magnetic behavior of MnCo2O4+δ spinel obtained by thermal decomposition of binary oxalates

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Product

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Activation of peroxymonosulfate with magnetic and recyclable Fe₃ O₄ @C/MnCo₂ O₄ nanocomposites for the decolorization of Acid Orange II

Activation of peroxymonosulfate with magnetic and recyclable Fe₃ O₄ @C/MnCo₂ O₄ nanocomposites for the decolorization of Acid Orange II