Tubular Structure Agglomerates of Calcium Carbonate Crystals Formed on a Cation-Exchange Membrane

Abstract

Crystallization of calcium carbonate was carried out by using 1 M calcium chloride and 1 M sodium carbonate and a specially designed crystallizer equipped with a cation-exchange membrane. The crystallizer is a jacketed cylindrical glass tube that was divided into two compartments by a cation-exchange membrane and placed horizontally. Calcium carbonate crystals grew on the surface of the cation-exchange membrane in the sodium carbonate solution side and formed self-assembled tubular agglomerates vertically against the membrane surface. The tube was named the CC-tube. The inner and outer diameters of the CC-tube obtained after 9 days of crystallization at 50°C was about 15 and 30 µm, respectively. The length was about 200-400 µm. Most of the CC-tubes were composed of small calcite crystals. The growing site of the tube was concluded to be the interface between the membrane and the tube rather than the top of tube.

Growth mechanism of the calcium carbonate tubes on a cation-exchange membrane

“…The tube grew longer with time. As reported in the previous paper, 11) the growing site of the tube is the bottom of tubes. It is reconfirmed by a fact that the bending part of the tube does not grow longer.…”

“…We have studied the role of membrane on the crystallization of calcium carbonate, 11) where 1 M sodium carbonate and 1 M calcium chloride solutions were separately placed in two compartments of the crystallizer that were divided by a cation-exchange membrane. Calcium ions permeated the membrane and reacted with carbonate ions in the sodium carbonate solution.…”

Fabrication of Tubular Structure Agglomerates of Calcium Carbonate by Using Collodion Film

“…As references reported, smooth tube may be composed of vaterite. 15 Furthermore, it is found from Figure 1a that the tube has a cap on the top. The cap is hemispheric and is composed of small crystals with cubic and rectangle shapes.…”

“…Tubular structure agglomerates of calcium carbonate crystals were synthesised on a cation-exchange membrane with 1 mol•L -1 CaCl 2 and 1 mol•L -1 Na 2 CO 3 solutions by Takiguchi et al 15 In their experiment, crystallization of calcium carbonate was carried out by using 1 mol•L -1 calcium chloride and 1 mol•L -1 sodium carbonate and a specially designed crystallizer equipped with a cation-exchange membrane. Calcium carbonate crystals grew on the surface of the cation-exchange membrane in the sodium carbonate solution side and formed self-assembled tubular agglomerates vertically against the membrane surface.…”

Surface and statistical analysis of CaCO3 crystals synthesized in the presence of fluorescein-tagged starch grafted with polyacrylic acid

“…Literature on crystallization of CaCO 3 showed that the nature of the template used and temperature affected the morphology of crystallized CaCO 3 [1][2][3][4][5][6][7][8][9]. However, elucidation of the surface properties of the crystallized CaCO 3 crystals in terms of the location of the polymeric additive is additionally important for application purposes.…”