Microwave-hydrothermal synthesis of nanostructured Na-birnessites and phase transformation by arsenic(III) oxidation

Dias, Anderson; Sá, Rodrigo Gomes; Spitale, Matheus C.; Athayde, Maycon; Ciminelli, Virgínia S. T.

doi:10.1016/j.materresbull.2007.06.019

Cited by 35 publications

(18 citation statements)

References 38 publications

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“…In the fingerprint region, the characteristic absorption peaks of birnessite are at 514, 478 and 416 cm −1 , being in accordance with a previous study . The absorption peaks at 514 and 478 cm −1 correspond to Mn−O stretching vibrations ,. Notably, MnO 6 also exhibits a characteristic peak at 514 cm −1 …”

Section: Resultssupporting

confidence: 79%

Efficient Electrochemical Water Oxidation and Oxidative Degradation of Rhodamine B: A Comparative Study Using High‐Purity Birnessites Containing Li⁺, Na⁺ or K⁺ Ions

et al. 2017

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High-purity birnessites, containing Na + , K + or Li + in the interlayer were prepared respectively with complexing agent EDTA at room temperature. The structural features and chemical compositions were characterized by X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis and field emission scanning electron microscopy. The electrocatalytic properties of these materials against oxygen evolution reaction (OER) in alkaline media were studied. Cyclic voltammetry and linear sweep voltammetry curves showed that Li-Bir had the highest water oxidation activity. Meanwhile, Li-Bir performed stably for 4000 s. For birnessites containing different alkali metals (K + , Na + or Li + ), the organic dye rhodamine B degradation rates were significantly different in acidic media. At pH 1, the degradation rate of Li-Bir was obviously higher than those of K-Bir and Na-Bir. The surface area of Li-Bir (107.282 cm 2 g À1 ) is much larger than those of Na-Bir (35.623) and K-Bir (11.900), indicating that specific surface area was one of the main factors affecting the OER activity and degradation efficiency of birnessite.

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Section: Resultssupporting

confidence: 79%

Efficient Electrochemical Water Oxidation and Oxidative Degradation of Rhodamine B: A Comparative Study Using High‐Purity Birnessites Containing Li⁺, Na⁺ or K⁺ Ions

et al. 2017

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“…Therefore, an oxidation step is often used to improve arsenic removal and fixation. Manganese oxides are known as effective oxidizers of As(III) to As(V) in natural environments and in water treatment units [6][7][8][9][10] . Among the series of manganese oxides, Mn 3 O 4 is particularly known to be an effective and inexpensive catalyst in various oxidation and reduction reactions 11,12 .…”

Section: Introductionmentioning

confidence: 99%

Preparation and application of a magnetic composite (Mn3O4/Fe3O4) for removal of As(III) from aqueous solutions

et al. 2012

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The introduction of magnetic properties in adsorbent materials has the aim of improving solid-liquid separation processes. In this work, a magnetic composite was synthesized through the precipitation of manganese oxide in the presence of magnetite particles using O 2 as an oxidant. The composite proved to be chemically and physically stable within a wide range of pH values. The composite characterization indicated that hausmannite (Mn 3 O 4 ) represents the precipitated manganese phase and that magnetite undergoes no phase transformation during the synthesis. The composite and Mn 3 O 4 particles were used to remove As(III) from aqueous solutions. The magnetic composite and Mn 3 O 4 sample presented high and similar affinity for As(III), with maximum sorptive capacities of 14 mg As g solid -1 (0.0048 mmol As m

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“…0.122) this figure shows also two peaks at 2θ= 12.3° and 24.9° identified as Na 0.55 Mn 2 O 4 . 1.5H 2 O peaks [7,8]. Unfortunately our attempts are failed in the identification of the extra peak indicated by black asterisk in x=0.33 pattern.…”

Section: Methodsmentioning

confidence: 87%

“…The electrical resistance vs. temperature was measured in 80 -300K temperature range, using two electrical contacts done on samples having a disk shape with a diameter of 10mm and a thickness of about 2mm. 1.5H 2 O (black colour) as published in [7,8] works. 0.122) this figure shows also two peaks at 2θ= 12.3° and 24.9° identified as Na 0.55 Mn 2 O 4 .…”

Section: Methodsmentioning

confidence: 99%

Synthesis, structural, magnetic and electrical properties of nominal La_0.67Ba_0.33-xNa_xMnO₃(0 ≤ x ≤ 0.33) manganites

Hcini

Zemni

Boudard

et al. 2012

EPJ Web of Conferences

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Abstract.Complete nominal solid solutions La 0.67 Ba 0.33-x Na x MnO 3 (0 ≤ x ≤ 0.33) have been elaborated by ceramic route at 1200°C. ICPAES chemical analysis and XRD Rietveld structure refinement revealed that the nominal Na content is not achieved by our ceramic method. The chemical formula should be rather written as La α Ba β Na λ MnO 3-δ with a significantly lower Na content (λ), than the nominal one (x), and with a slight deficit (δ) in oxygen content, leading to the appearance of two minor secondary phases identified as Mn 3 O 4 and Na 0.55 Mn 2 O 4 . 1.5H 2 O. Magnetization and electrical resistance vs. temperature show paramagnetic/semiconductor -ferromagnetic/metallic transitions with only a slight decrease in magnetic and electrical transition temperatures when Na content increases. Such amount of this decrease is not expected according to the nominal Na content giving a significant difference between nominal and experimental Mn 4+ /Mn 3+ ratios.

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Microwave-hydrothermal synthesis of nanostructured Na-birnessites and phase transformation by arsenic(III) oxidation

Cited by 35 publications

References 38 publications

Efficient Electrochemical Water Oxidation and Oxidative Degradation of Rhodamine B: A Comparative Study Using High‐Purity Birnessites Containing Li⁺, Na⁺ or K⁺ Ions

Efficient Electrochemical Water Oxidation and Oxidative Degradation of Rhodamine B: A Comparative Study Using High‐Purity Birnessites Containing Li⁺, Na⁺ or K⁺ Ions

Preparation and application of a magnetic composite (Mn3O4/Fe3O4) for removal of As(III) from aqueous solutions

Synthesis, structural, magnetic and electrical properties of nominal La_0.67Ba_0.33-xNa_xMnO₃(0 ≤ x ≤ 0.33) manganites

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Microwave-hydrothermal synthesis of nanostructured Na-birnessites and phase transformation by arsenic(III) oxidation

Cited by 35 publications

References 38 publications

Efficient Electrochemical Water Oxidation and Oxidative Degradation of Rhodamine B: A Comparative Study Using High‐Purity Birnessites Containing Li+, Na+ or K+ Ions

Efficient Electrochemical Water Oxidation and Oxidative Degradation of Rhodamine B: A Comparative Study Using High‐Purity Birnessites Containing Li+, Na+ or K+ Ions

Preparation and application of a magnetic composite (Mn3O4/Fe3O4) for removal of As(III) from aqueous solutions

Synthesis, structural, magnetic and electrical properties of nominal La0.67Ba0.33-xNaxMnO3(0 ≤ x ≤ 0.33) manganites

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Efficient Electrochemical Water Oxidation and Oxidative Degradation of Rhodamine B: A Comparative Study Using High‐Purity Birnessites Containing Li⁺, Na⁺ or K⁺ Ions

Efficient Electrochemical Water Oxidation and Oxidative Degradation of Rhodamine B: A Comparative Study Using High‐Purity Birnessites Containing Li⁺, Na⁺ or K⁺ Ions

Synthesis, structural, magnetic and electrical properties of nominal La_0.67Ba_0.33-xNa_xMnO₃(0 ≤ x ≤ 0.33) manganites