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Surface Modification and Planar Defects of Calcium Carbonates by Magnetic Water Treatment.

Liu CZ, Lin CH, Yeh MS, Chao YM, Shen P - Nanoscale Res Lett (2010)

Bottom Line: Calcite were found to form faceted nanoparticles having 3x (01̄14) commensurate superstructure and with well-developed {112̄0} and {101̄4} surfaces to exhibit preferred orientations.The (hkil)-specific coalescence of calcite and rapid lath growth of aragonite under the combined effects of Lorentz force and a precondensation event account for a beneficial larger particulate/colony size for the removal of the carbonate scale from the steel substrate.The coexisting magnetite particles have well-developed {011} surfaces regardless of MWT.

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ABSTRACT
Powdery calcium carbonates, predominantly calcite and aragonite, with planar defects and cation-anion mixed surfaces as deposited on low-carbon steel by magnetic water treatment (MWT) were characterized by X-ray diffraction, electron microscopy, and vibration spectroscopy. Calcite were found to form faceted nanoparticles having 3x (01̄14) commensurate superstructure and with well-developed {112̄0} and {101̄4} surfaces to exhibit preferred orientations. Aragonite occurred as laths having 3x (01̄1) commensurate superstructure and with well-developed (01̄1) surface extending along [100] direction up to micrometers in length. The (hkil)-specific coalescence of calcite and rapid lath growth of aragonite under the combined effects of Lorentz force and a precondensation event account for a beneficial larger particulate/colony size for the removal of the carbonate scale from the steel substrate. The coexisting magnetite particles have well-developed {011} surfaces regardless of MWT.

No MeSH data available.


Schematic drawings of the unrelaxed () surface of aragonite, assuming Ca (red) and C (green, representing CO32−) atoms have point charges for the cation–anion mixed surfaces
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Figure 10: Schematic drawings of the unrelaxed () surface of aragonite, assuming Ca (red) and C (green, representing CO32−) atoms have point charges for the cation–anion mixed surfaces

Mentions: In the present scale, the aragonite predominantly formed lath with unusual () habit plane extending along [100] direction. This can be attributed to the anisotropic growth under the combined effects of PBC and precondensation in a dynamic process, as suggested for other molecular/ionic crystals with orthorhombic crystal structure such as BaSO4 and KC1O4 [[42]]. The () habit plane of aragonite, a cation–anion mixed plane given the space group Pcmn [[41]], could be derived from face-centered planes of parent vaterite and/or calcite i.e. the F face with at least two PBCs [[24]] (Fig. 10). The [100] direction of aragonite has the shortest bonding distance between the nearest Ca2+ and CO32− neighbor assuming with point charges [[41]], and hence a favorable growth direction with the most strong PBC for the preferred accommodation of the ions and/or ion clusters from solution.


Surface Modification and Planar Defects of Calcium Carbonates by Magnetic Water Treatment.

Liu CZ, Lin CH, Yeh MS, Chao YM, Shen P - Nanoscale Res Lett (2010)

Schematic drawings of the unrelaxed () surface of aragonite, assuming Ca (red) and C (green, representing CO32−) atoms have point charges for the cation–anion mixed surfaces
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2991221&req=5

Figure 10: Schematic drawings of the unrelaxed () surface of aragonite, assuming Ca (red) and C (green, representing CO32−) atoms have point charges for the cation–anion mixed surfaces
Mentions: In the present scale, the aragonite predominantly formed lath with unusual () habit plane extending along [100] direction. This can be attributed to the anisotropic growth under the combined effects of PBC and precondensation in a dynamic process, as suggested for other molecular/ionic crystals with orthorhombic crystal structure such as BaSO4 and KC1O4 [[42]]. The () habit plane of aragonite, a cation–anion mixed plane given the space group Pcmn [[41]], could be derived from face-centered planes of parent vaterite and/or calcite i.e. the F face with at least two PBCs [[24]] (Fig. 10). The [100] direction of aragonite has the shortest bonding distance between the nearest Ca2+ and CO32− neighbor assuming with point charges [[41]], and hence a favorable growth direction with the most strong PBC for the preferred accommodation of the ions and/or ion clusters from solution.

Bottom Line: Calcite were found to form faceted nanoparticles having 3x (01̄14) commensurate superstructure and with well-developed {112̄0} and {101̄4} surfaces to exhibit preferred orientations.The (hkil)-specific coalescence of calcite and rapid lath growth of aragonite under the combined effects of Lorentz force and a precondensation event account for a beneficial larger particulate/colony size for the removal of the carbonate scale from the steel substrate.The coexisting magnetite particles have well-developed {011} surfaces regardless of MWT.

View Article: PubMed Central - HTML - PubMed

ABSTRACT
Powdery calcium carbonates, predominantly calcite and aragonite, with planar defects and cation-anion mixed surfaces as deposited on low-carbon steel by magnetic water treatment (MWT) were characterized by X-ray diffraction, electron microscopy, and vibration spectroscopy. Calcite were found to form faceted nanoparticles having 3x (01̄14) commensurate superstructure and with well-developed {112̄0} and {101̄4} surfaces to exhibit preferred orientations. Aragonite occurred as laths having 3x (01̄1) commensurate superstructure and with well-developed (01̄1) surface extending along [100] direction up to micrometers in length. The (hkil)-specific coalescence of calcite and rapid lath growth of aragonite under the combined effects of Lorentz force and a precondensation event account for a beneficial larger particulate/colony size for the removal of the carbonate scale from the steel substrate. The coexisting magnetite particles have well-developed {011} surfaces regardless of MWT.

No MeSH data available.