Effect of Dendrimers on the Crystallization of Calcium Carbonate in Aqueous Solution

2003 ◽  
pp. 141-158 ◽  
Author(s):  
Kensuke Naka
2008 ◽  
Vol 20 (8) ◽  
pp. 761-763 ◽  
Author(s):  
Lin Yang ◽  
Feng Ye ◽  
Ruimin Xing ◽  
Baofang Zhang ◽  
Qiushi Ren

2021 ◽  
Vol 2071 (1) ◽  
pp. 012007
Author(s):  
M R M Roslan ◽  
N F M Nasir ◽  
N F Mohammad ◽  
C E Meng ◽  
M S Mohamed ◽  
...  

Abstract Hydroxyapatite (HA) powders were prepared via chemical solution through aqueous solution of calcium hydroxide and phosphoric acid. The calcium precursor was extracted from the calcium carbonate of Corbiculacea shells while the phosphate precursor originated from the commercially available phosphoric acid. The final product of HA powders is then manipulated through the sintering process at 500°C while the other sample was used as it is. XRD result shows significant changes in its crystallinity, crystallite size and lattice parameters after the sintering process. By sintering the HA, the crystallite size and crystallinity were increases as much as 6.25% and 5.31% respectively. SEM on the other hand showed different morphology for both sintering and non-sintering HA powders. For the sintering HA, the grains size is higher which is 5.00μm compared to non-sintering HA which is 3.91μm due to the agglomeration.


Author(s):  
S.R. Alimbekov ◽  
◽  
F.G. Ishmuratov ◽  
V.V. Nosov ◽  
A.I. Voloshin ◽  
...  

The influence of the electromagnetic field (EMF) on the corrosion of structural carbon steel in a 3% aqueous solution of sodium chloride in the presence of CO2 was studied. It is shown that the EMF increases the corrosion rate of steel by 1.13 times in a 3% aqueous solution of NaCl in the presence of CO2. When Ca2+ ions are added to the solution, the corrosion rate of steel decreases under the influence of an electromagnetic field. It is assumed that the formation of CaCO3 in the near-surface layer of the solution and its adsorption on the metal surface prevents the development of corrosion. The influence of the electromagnetic field generated in the frequency range from 100 to 200 kHz on the crystallization of CaCO3 from supersaturated aqueous solutions on the model system CaCl2 – NaHCO3 – FeSO4 is studied. It was found that Fe2+, rather than EMF, has a more significant effect on salt deposition. The efficiency of the effect of Fe2+ on the inhibition of salt deposition in the model of mineralized water CaCl2-NaHCO3 is 11.5% higher than when exposed to EMF. During the crystallization of CaCO3, the predominant formation of aragonite is observed. In the presence of iron ions and under the influence of EMF, there was a decrease in the formation of aragonite and an increase in the formation of calcite and vaterite. Keywords: electromagnetic field; corrosion; carbon steel; iron ions; scale deposition; crystallization; calcium carbonate.


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