Enthalpy of formation of natural hydrous iron phosphate: Vivianite

Ogorodova, L. P.; Вигасина, М. Ф.; Melchakova, L. V.; Rusakov, V. S.; Kosova, D. A.; Ксенофонтов, Д. А.; Bryzgalov, I. A.

doi:10.1016/j.jct.2017.02.020

Cited by 40 publications

(13 citation statements)

References 28 publications

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“…Thermal features of vivianite have not been understood in all details. Some studies suggest that temperature loss (together 25% loss of mass) due to one-step thermal decomposition occurs between 70 and 500 °C with a peak at about 150 °C (Ogorodova et al 2017). In contrast, Földvári (2011) suggests that vivianite loses its crystalline water through an endothermic reaction between 250 and 300 °C; this author notes, however, that crystalline water may be removed in several steps, too.…”

Section: Resultsmentioning

confidence: 94%

Vivianite formation as indicator of human impact in porous sediments

Csámer

Papp²,

Kristály

et al. 2021

Environ Earth Sci

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Environmental geological survey of a chemical works situated in NE Hungary has been performed for decades. Up till now, several hundreds of drillings of different depths as well as engineering geological soundings have been carried out in the area. Vivianite has been found in a discrete part of a drilling in a gray, silty bed at the depth 6.8–8.5 m. Vivianite was analyzed using X-ray powder diffraction (XRPD), thermal analysis (TG/DTG), and scanning electron microscopic and energy dispersive spectrometry (SEM–EDS) techniques. To demonstrate the spatial distribution of hydrochemical parameters and selected chemical constituents the available data concerning drillings and hydrochemical analyses were collected and evaluated, and field measurements were also performed. For mapping the distribution of relevant physico-chemical parameters and chemical constituents kriging interpolation method was used. Archive aerial photographs demonstrate that a coffered, earth-bedded reservoir for storing huge amounts of extracted plant debris is situated in the vicinity of the drilling. Our study suggests that orthophosphate derived from decomposing biomass entered the groundwater and accumulated within the lowest permeability zone of the intact bedrock. Therefore, the discrete appearance of vivianite in the drilling can be regarded, at least partly, the result of a man-induced mineralogical process.

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Section: Resultsmentioning

confidence: 94%

Vivianite formation as indicator of human impact in porous sediments

Csámer

Papp²,

Kristály

et al. 2021

Environ Earth Sci

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“…[44] The vibrational modes of Fe-(PO 4 ) were detected at 548 and 1059 cm À1 and confirmed the existence of vivianite. [46] In addition, GO was confirmed by the band detected at 1458.5 cm À1 for the C-O group. [47] 3.3 | XPS XPS spectroscopy was performed to confirm elemental existence and formation of the TNC HAP/vivianite/GO.…”

Section: Ftirmentioning

confidence: 93%

Microstructure, morphology and physicochemical properties of nanocomposites containing hydroxyapatite/vivianite/graphene oxide for biomedical applications

et al. 2021

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Designing a nanocomposite that accumulates biocompatibility and antimicrobial behaviour is an essential requirement for biomedical applications. Hydroxyapatite (HAP), graphene oxide, and vivianite in one ternary nanocomposite with three phases and shapes led to an increase in cell viability to 97.6% ± 4 for the osteoblast cells in vitro. The obtained nanocomposites were investigated for their structural features using X-ray diffraction, while the microstructure features were analyzed using a scanning electron microscope (SEM) and a transmission electron microscope. The analysis showed a decrease in the crystal size to 13 nm, while the HAP grains reached 30 nm.The elongated shape of vivianite reached 200 nm on SEM micrographs. The monoclinic and hexagonal crystal systems of HAP and vivianite were presented in the ternary nanocomposite. The maximum roughness peak height reached 236.1 nm for the ternary nanocomposite from 203.3 nm, while the maximum height of the roughness parameter reached 440.7 nm for the di-nanocomposite of HAP/graphene oxide from 419.7 nm. The corrosion current density reached 0.004 μA/cm 2 . The ferrous (Fe 2+ ) and calcium (Ca 2+ ) ions released were measured and confirmed. Therefore, the morphology of the nanocomposites affected bacterial activity. This was estimated as an inhibition zone and reached 14.5 ± 0.9 and 13.4 ± 1.1 mm for Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) after 24 h. The increase in viability and the antibacterial activity refer to the compatibility of the nanocomposite in different medical applications.

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“…[7][8][9] In Europe, the sedimentary deposits found in Germany, Flanders and, specially, The Netherlands were of particular historical importance. 10 The geochemical processes involved in its formation have been reviewed by Rothe et al 9 and its structural and thermodynamic properties by Capitelli et al and by Ogorodova et al 11,12 With the formula Fe 3 (PO 4 ) 2 Á8H 2 O, vivianite is colourless and translucent in its pristine state, but after mined, upon exposure to light and air, it turns to green, then to blue and, finally, to a very dark bluish-black. This colour change results from the partial oxidation of ferrous iron into ferric iron and the shift in the balance between them.…”

Section: Introductionmentioning

confidence: 99%

“…In Europe, the sedimentary deposits found in Germany, Flanders and, specially, The Netherlands were of particular historical importance . The geochemical processes involved in its formation have been reviewed by Rothe et al and its structural and thermodynamic properties by Capitelli et al and by Ogorodova et al…”

Section: Introductionmentioning

confidence: 99%

Identification of vivianite, an unusual blue pigment, in a sixteenth century painting and its implications

Cruz

Eires

Dias

et al. 2017

Color Research & Application

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Vivianite, a blue pigment employed in the past practically only in Northern and Central Europe, but with very limited use, was identified in an early sixteenth century painting, stylistically with Flemish features, from a church in Portugal. The identification of this iron phosphate mineral was made by SEM-EDS based on the atomic ratio between phosphorus and iron in layers of blue paint (area analysis) and in particles of these same layers (spot analysis). This painting, about which there is no document to prove its authorship, becomes the first case, known in detail, of a sixteenth century painting containing vivianite. Moreover, this find and the presence of a chalk ground, also identified, strongly support the hypothesis of being a Flemish painting.

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Enthalpy of formation of natural hydrous iron phosphate: Vivianite

Cited by 40 publications

References 28 publications

Vivianite formation as indicator of human impact in porous sediments

Vivianite formation as indicator of human impact in porous sediments

Microstructure, morphology and physicochemical properties of nanocomposites containing hydroxyapatite/vivianite/graphene oxide for biomedical applications

Identification of vivianite, an unusual blue pigment, in a sixteenth century painting and its implications

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