The bio-mimetic synthesis of calcium carbonate (CaCO3) is one of the most abundant bio-minerals and had such industrial fields as paper, rubber, plastic, paint and more. The application of CaCO3 particles is determined by a number of strictly defined parameters such as morphology, structure, size, ...
The bio-mimetic synthesis of calcium carbonate (CaCO3) is one of the most abundant bio-minerals and had such industrial fields as paper, rubber, plastic, paint and more. The application of CaCO3 particles is determined by a number of strictly defined parameters such as morphology, structure, size, specific surface area, brightness, oil adsorption, chemical purity, and so on. One of the most important parameters is particle morphology.
The chosen substances were Ethylenediaminetetraacetic Acid(EDTA), Diethylene Triamine Pentaacetic Acid (DTPA), Citric Acid (CIT) and Poly acrylic Acid (PAA). EDTA has four carboxylic groups and two amine groups. It is quite and effective complexing agent for calcium at medium and high pH. Berner et al. and Hoch et al. Reports on it having no effect on the crystal growth of aragonite. DTPA is the largest molecule with five carboxylic groups stretching out in the form of Aceto groups from three amine groups. In solution DTPA forms complexes with both one and two calcium ions. CIT has three carboxylic groups and one hydroxylic group. It forms complexes with calcium in water at medium and high pH. PAA consists of a benzoic ring with four carboxylic groups. It is the least efficient complexing agent for calcium. In this work, we researched the crystallization of CaCO3 particles from aqueous solution in the absence and presence of EDTA, DTPA, CIT, PAA. Morphology of calcium carbonate was changed by the temperature and concentration of additives. Particle size change without additives at low temperature and calcite of low equilibrium constant was made. But at high temperature we confirmed that aragonite of high equilibrium constant is thermodynamically more stabilized than calcite through the experimentation. When EDTA 0.0025g was added, we found out that the shape of Calcite and Aragonite was controlled at low temperature 40℃. It could be confirmed that below 1µm Calcite of single shape was shown in adding PMA 0.0025g at reaction temperature 20℃, even though Mean particle size was smally formed as 10 µm in adding PAA. The crystal growth of calcite and aragonite was retarded by the presence of EDTA and CIT, and the retardation increases with increasing additive concentration. The growth retardation is overall much stronger for aragonite than for calcite. Variation of XRD intensity shows a dependency on temperature and concentration. Intensity of aragonite is higher than calcite at high concentration.
The bio-mimetic synthesis of calcium carbonate (CaCO3) is one of the most abundant bio-minerals and had such industrial fields as paper, rubber, plastic, paint and more. The application of CaCO3 particles is determined by a number of strictly defined parameters such as morphology, structure, size, specific surface area, brightness, oil adsorption, chemical purity, and so on. One of the most important parameters is particle morphology.
The chosen substances were Ethylenediaminetetraacetic Acid(EDTA), Diethylene Triamine Pentaacetic Acid (DTPA), Citric Acid (CIT) and Poly acrylic Acid (PAA). EDTA has four carboxylic groups and two amine groups. It is quite and effective complexing agent for calcium at medium and high pH. Berner et al. and Hoch et al. Reports on it having no effect on the crystal growth of aragonite. DTPA is the largest molecule with five carboxylic groups stretching out in the form of Aceto groups from three amine groups. In solution DTPA forms complexes with both one and two calcium ions. CIT has three carboxylic groups and one hydroxylic group. It forms complexes with calcium in water at medium and high pH. PAA consists of a benzoic ring with four carboxylic groups. It is the least efficient complexing agent for calcium. In this work, we researched the crystallization of CaCO3 particles from aqueous solution in the absence and presence of EDTA, DTPA, CIT, PAA. Morphology of calcium carbonate was changed by the temperature and concentration of additives. Particle size change without additives at low temperature and calcite of low equilibrium constant was made. But at high temperature we confirmed that aragonite of high equilibrium constant is thermodynamically more stabilized than calcite through the experimentation. When EDTA 0.0025g was added, we found out that the shape of Calcite and Aragonite was controlled at low temperature 40℃. It could be confirmed that below 1µm Calcite of single shape was shown in adding PMA 0.0025g at reaction temperature 20℃, even though Mean particle size was smally formed as 10 µm in adding PAA. The crystal growth of calcite and aragonite was retarded by the presence of EDTA and CIT, and the retardation increases with increasing additive concentration. The growth retardation is overall much stronger for aragonite than for calcite. Variation of XRD intensity shows a dependency on temperature and concentration. Intensity of aragonite is higher than calcite at high concentration.
Keyword
#탄산칼슘
#형상 제어
#열역학적
#화학공학
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