Synthesis of Ni ferrite and Co ferrite rodlike particles by superposition of a constant magnetic field

2008 ◽  
Vol 23 (6) ◽  
pp. 1764-1775 ◽  
Author(s):  
Fernando Vereda ◽  
Juan de Vicente ◽  
Roque Hidalgo-Álvarez
Keyword(s):  
Magnetic Field ◽  
Atomic Absorption ◽  
Absorption Spectroscopy ◽  
Atomic Absorption Spectroscopy ◽  
Potassium Nitrate ◽  
X Ray ◽  
Average Aspect Ratio ◽  
Rodlike Particles ◽  
Dependent Observation ◽  
Lower Saturation

We report the fabrication of micron-sized rodlike particles of nonstoichiometric Co and Ni ferrites by aging coprecipitated Fe(OH)2 and M(OH)2—where M is either Ni or Co—at 90 °C in the presence of an external magnetic field (B ≈ 405 mT). Potassium nitrate was used as a mild oxidant. Resultant particles were analyzed by means of electron microscopy, x-ray powder diffraction (XRD), magnetometry, energy dispersive x-ray (EDX) spectrometry, and atomic absorption spectroscopy. Rodlike particles of both types of ferrite exhibited a relatively uniform thickness, an average aspect ratio close to 10, and have a spinel crystalline structure. EDX spectrometry and atomic absorption spectroscopy confirmed the incorporation of Ni2+ and Co2+ in the respective ferrite particles. The incorporation of Co2+ led to non-negligible remanence and coercivity. The incorporation of Ni2+ led to a lower saturation magnetization, whereas the remanence and coercivity of the Ni ferrite were very low, still typical of a soft ferrimagnetic material. The mechanism of formation of the rodlike particles was investigated by the time-dependent observation of growing Ni ferrite rods.

Decomposition of Some Skarn-Rock Samples in Neutral and Basic Molten Potassium Nitrate for the Extraction and Determination of Iron

1996 ◽  
Vol 49 (2) ◽  
pp. 261 ◽  
Author(s):  
JK Mujumba ◽  
BD James ◽  
SA Tariq
Keyword(s):  
Atomic Absorption ◽  
Absorption Spectroscopy ◽  
Atomic Absorption Spectroscopy ◽  
Iron Content ◽  
Potassium Nitrate ◽  
Total Iron ◽  
Total Iron Content ◽  
X Ray ◽  
Rock Samples

Five skarn -rock samples were heated with KNO3 and with a solution of 5% KOH in KNO3 for 2 h at 450°C. The decomposed samples were cooled, dissolved in water and filtered. Iron was extracted from each residue as well as from the original samples by hot conc. HCl , and determined by atomic absorption spectroscopy. These results were compared with the known (X-ray fluorescence) total iron content of the original samples. The amount of iron extracted with HCl from the skarn samples was 3-11% lower, while that extracted after heating with KNO3 alone was 2-4% lower, than the amount present according to the X-ray fluorescence results. However, the amount of iron extracted from the samples treated with a solution of KOH in KNO3 was comparable to that determined by X-ray fluorescence.

The Shape of Analytical Curves in Zeeman Atomic Absorption Spectroscopy. II. Theoretical Analysis and Experimental Evidence for Absorption Maximum in the Analytical Curve

1980 ◽  
Vol 34 (4) ◽  
pp. 464-472 ◽  
Author(s):  
M. T. C. De Loos-Vollebregt ◽  
L. de Galan
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Atomic Absorption ◽  
Absorption Spectroscopy ◽  
Atomic Absorption Spectroscopy ◽  
Stray Light ◽  
Strong Nonlinearity ◽  
Analytical Curve ◽  
Pass Through ◽  
The Magnetic Field

The analysis of the shape of analytical curves in Zeeman atomic absorption spectroscopy has been extended toward higher concentrations. Nonlinearity in the conventional atomic absorption signal due to stray light or nonlinear electronic response causes both theoretically calculated and experimental analytical curves in Zeeman atomic absorption to go through a maximum at a certain concentration. The height and the position of the maximum depend on the magnetic system used, the strength of the magnetic field and the amount of nonlinearity. In all magnetic systems the maximum attainable absorbance is enhanced by increasing the magnetic field strength and decreasing the amount of nonlinearity. Over the normal concentration range a maximum in the Zeeman atomic absorption analytical curve only occurs under the extreme conditions of a very weak magnetic field and strong nonlinearity. Ultimately, however, all Zeeman atomic absorption analytical curves pass through a maximum unless the optics and electronics are perfect. For practical systems strong ac modulated magnetic fields are to be preferred over dc magnetic fields.

scholarly journals Synthesis and Characterisation of New {Fe2CrO} Heterotrinuclear Iron-chromium Clusters

2021 ◽  
Author(s):  
Viorina Gorinchoy ◽  
Olesea Cuzan ◽  
Silvia Melnic ◽  
Oleg Petuhov ◽  
Sergiu Shova
Keyword(s):  
Thermal Properties ◽  
Atomic Absorption ◽  
Absorption Spectroscopy ◽  
Elemental Analysis ◽  
Atomic Absorption Spectroscopy ◽  
X Ray ◽  
Heteronuclear Complexes ◽  
The Stability ◽  
Iron Chromium ◽  
Salicylic Acids

Two new μ3-oxo trinuclear heterometallic Fe2IIICrIII complexes with furan-2-carboxylic and salicylic acids with the composition: [Fe2CrO(C4H3OCOO)6(CH3OH)3]NO3·0.5CH3OH and [Fe2CrO(C6H4(OH)COO)7(CH3OH)2]·2DMA were synthesized starting from iron(III) and chromium(III) salts mixture. The complexes structures were confirmed by elemental analysis, IR, Mössbauer spectroscopies, and X-ray analysis. The atomic absorption spectroscopy confirmed that the iron: chromium ratio is 2:1. The thermal properties of both heteronuclear complexes have been investigated in oxidizing and inert atmospheres revealing the stability of the trinuclear core up to 170 and 220°C, respectively.

scholarly journals X-Ray Fluorescence Determination of Manganese in FD&C Blue No. 1

1998 ◽  
Vol 81 (1) ◽  
pp. 89-92 ◽  
Author(s):  
Nancy M Hepp
Keyword(s):  
Confidence Interval ◽  
Atomic Absorption ◽  
Absorption Spectroscopy ◽  
Atomic Absorption Spectroscopy ◽  
Limit Of Detection ◽  
X Ray ◽  
Fluorescence Determination

Abstract An X-ray fluorescence (XRF) method was developed for determining manganese in FD&C Blue No. 1 from simply prepared pressed pellets. Results were compared with those of atomic absorption spectroscopy (AAS) of acid-digested or ashed samples. Levels of manganese determined by XRF and AAS were equivalent. The limit of detection (3σ) for the XRF method was 3µg manganese/g dye. The 95% confidence interval at the specification level was 100 ± 10 μg manganese/g dye

Characterization of the Non-Polymeric Fraction of Post-Consumer LCD Monitor Housings

2018 ◽  
Vol 912 ◽  
pp. 218-223
Author(s):  
Natalia Massaro ◽  
Cátia Fredericci ◽  
Samuel Marcio Toffoli ◽  
Ticiane Sanches Valera
Keyword(s):  
Atomic Absorption ◽  
Absorption Spectroscopy ◽  
Atomic Absorption Spectroscopy ◽  
Xrd Analysis ◽  
Inorganic Materials ◽  
Ambient Atmosphere ◽  
X Ray Diffraction ◽  
X Ray ◽  
Computer Monitors ◽  
Polymeric Fraction

This work aims to characterize the non-polymeric components, usually present as additives to perform different functions, present in the polymer housing of post-consumer computer monitors, in order to help finding the most adequate recycling destination for such material. The non-polymeric fraction was characterized by thermogravimetry (TG), loss on ignition (LOI), chemical analysis by X-ray fluorescence (XRF), and atomic absorption spectroscopy, scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), and X-ray diffraction (XRD). TG analysis indicated that the polymer has about 4 wt% of inorganic materials (performed in N2 atmosphere), whereas LOI (performed in ambient atmosphere) indicated just 0.07 wt%. The XRF, SEM/EDS analyses, and atomic absorption spectroscopy of the post-fired material confirmed the presence of many elements. Nonetheless, toxicological relevant elements showed acceptable concentration levels, below 0.01 ppm. The XRD analysis indicated the presence of crystalline phases based on CaCO3, SiO2 and TiO2.

Sign in / Sign up

Export Citation Format

Share Document