学位論文

アミノ酸添加溶液から析出する炭酸カルシウムの多形と形態

The polymorphs and morphologies of calcium carbonates precipitated from solutions with amino acids

jpn

2012-03-24

Not Applicable (or Unknown)

2012-03-24

修士(工学)

工学研究科物質科学専攻; 指導教授: 石垣隆正

The addition of amino acid additives on the polymorphs and the crystal morphologies of calcium carbonates precipitated from the saturated solution of Ca(HCO3)2 was characterized by XRD and SEM. The calcite crystals of rhombic shape were precipitated from the solutions with arginine, while a mixture of calcite crystals, needle-like aragonite, and sheet-shaped vaterite was precipitated from the solutions without amino acid, and with glutamic acid and glycine. These results have relevance to the formation mechanism of calcium carbonates and suggest that their polymorphs and morphologies are related to the effect of pH values rather than the adsorption of amino acids in solutions. It is thought that CO3 2- ions play an important role in the formation of calcite crystals at high pH, while HCO3- ions contribute to the formation of calcite, aragonite, and vaterite at low pH. The adsorption of glutamic acid and glycine was considered to stabilize {0001} planes of vaterite.

Thesis