The behaviour of precipitating systems of Mg, Ca, Sr, Ba, Mn and Zn-oxalates in aqueous and in the ethanol medium at the room temperature

Novosel, B.; Težak, B.; Čular-Elijaš, Z.; Haraminčić, A.; Valentina, Jakopović,; Ryznar, B.; Štiglić, M.; Vidas, M.

doi:10.1007/bf01382124

Cited by 2 publications

(3 citation statements)

References 10 publications

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“…It can also be assumed that a change in the chemistry of the crystallization medium shifts the boundaries of weddellite formation. As shown by Novosel et al [ 27 ], after a specific change in the concentrations of the main components of the crystallization medium and pH, weddellite began to crystallize first, while whewellite precipitated only after some time. To further study the thermodynamic conditions of calcium oxalates formation, additional special experiments are required.…”

Section: Discussionmentioning

confidence: 95%

Biofilm Medium Chemistry and Calcium Oxalate Morphogenesis

2021

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The present study is focused on the effect of biofilm medium chemistry on oxalate crystallization and contributes to the study of the patterns of microbial biomineralization and the development of nature-like technologies, using the metabolism of microscopic fungi. Calcium oxalates (weddellite and whewellite in different ratios) were synthesized by chemical precipitation in a weakly acidic environment (pH = 4–6), as is typical for the stationary phase of micromycetes growth, with a ratio of Ca2+/C2O42− = 4.0–5.5, at room temperature. Additives, which are common for biofilms on the surface of stone in an urban environment (citric, malic, succinic and fumaric acids; and K+, Mg2+, Fe3+, Sr2+, SO42+, PO43+ and CO32+ ions), were added to the solutions. The resulting precipitates were studied via X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS). It was revealed that organic acids, excreted by micromicetes, and some environmental ions, as well as their combinations, significantly affect the weddellite/whewellite ratio and the morphology of their phases (including the appearance of tetragonal prism faces of weddellite). The strongest unique effect leading to intensive crystallization of weddellite was only caused by the presence of citric acid additive in the medium. Minor changes in the composition of the additive components can lead to significant changes in the weddellite/whewellite ratio. The effect of the combination of additives on this ratio does not obey the law of additivity. The content of weddellite in the systems containing a representative set of both organic acids and environmental ions is ~20 wt%, which is in good agreement with natural systems.

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Section: Discussionmentioning

confidence: 95%

Biofilm Medium Chemistry and Calcium Oxalate Morphogenesis

2021

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“…The marked variation in the loaded and experimentally evaluated composition of oxalate precursor is because of the different rate of precipitation of the zinc oxalate (higher rate) and manganese oxalate. 22 Thermogravimetric analysis of the oxalate precursor carried out in flowing nitrogen shows two regions of weight loss, the first at 150 C corresponds to loss of two water molecules and the second at 400 C corresponds to loss of carbon dioxide and carbon monoxide (Fig. S3 †).…”

Section: Resultsmentioning

confidence: 99%

“…S3 †). It may be noted that synthesis of Zn-Mn-O compounds and earlier studies on the phase diagram 21,22 have been carried out above 400 C. There is no report on the synthesis of Zn-Mn-O phases at temperatures below 400 C and at ambient pressure. Although, the hydrothermal route for the synthesis of the Mn(III) spinel ZnMn 2 O 4 is carried out at 120 C.…”

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confidence: 99%

Stabilization of Mn(iv) in nanostructured zinc manganese oxide and their facile transformation from nanospheres to nanorods

et al. 2011

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Nanostructured ternary manganese(IV) oxides are of importance as electrode materials. A lowtemperature, precursor mediated route has been designed to obtain ternary oxides containing Mn(IV) and Zn(II) at ambient pressure. The defect spinel, Zn 0.83 (Mn 1.42 Zn 0.34 )O 4 was obtained by annealing at optimal conditions after the thermal decomposition of oxalates of zinc and manganese co-precipitated at room temperature. This is the first report of a low temperature (250 C) and normal atmospheric pressure synthesis of a ternary zinc manganese oxide containing purely tetravalent manganese. Rietveld refinement indicates zinc occupancy in both tetrahedral and octahedral sites with the refined composition of (Zn 0.83 ) tet (Mn

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The behaviour of precipitating systems of Mg, Ca, Sr, Ba, Mn and Zn-oxalates in aqueous and in the ethanol medium at the room temperature

Cited by 2 publications

References 10 publications

Biofilm Medium Chemistry and Calcium Oxalate Morphogenesis

Biofilm Medium Chemistry and Calcium Oxalate Morphogenesis

Stabilization of Mn(iv) in nanostructured zinc manganese oxide and their facile transformation from nanospheres to nanorods

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