Synthesize Nano-CaCO₃ Particles With Bubble Biomimetic Templates

CaCO₃ nano-particles are widely used in many areas ranging from industries of rubber, plastics, inks and paper, etc. to the improvement of medicine as a sustained-release drug carrier and targeting role. In this paper, different size of spherical CaCO₃ nano-particle with narrow size dispersion was successfully synthesized using the foam films biomimetic templates, via controlling the gas velocity, concentration of foaming agent, sodium carbonate and calcium chloride concentration. The framework and structure were characterized by means of TEM, XRD, and it was found that its chemical structure is like calcite crystal. By controlling the above conditions, particles with diameters from 30 nm to 200 nm could be got. Suitable surfactant as foaming agent was selected according to their salt-tolerance, foaming ability, and foam stability. Electric conductivity method was used to quantificationally measure the content of liquid of the upper foams before coming into contact with each other, it was found that the initial conductivity was low, while gradually increased to a stable platform, which provided a direction for the scale production. The remaining content of liquid was measured after the bubble burst, and the result showed that the content of liquid increased with the increase of gas velocity, which increased firstly and then decrease with the concentration of surfactant rising. This phenomenon accords well with the trend of the variation of diameter CaCO₃ nano-particles. Through analyzing the growth mechanism of calcium carbonate in the foam films, it is concluded that the increase of liquid amount in the foam and the thickness of the foam films is a key factor for controlling of the size of particles. Porous ceramic disc with more and bigger aperture was used to form foam containing bigger bubbles, and as a result the size of Nano-CaCO₃ particle got using this template became larger, too. By analyzing the content of liquid in the foam, we found that the foam films with bigger bubbles containing much more liquid than that with smaller bubbles. The effect of addition of polymer, such as sodium carboxymethyl cellulose, on the morphology and size of CaCO₃ synthesized using foam films as template was studied, and flake Nano-CaCO₃ was got in this situation, and themechanism was discussed in the paper.The innovations in the thesis are as follows:1. In this paper nano-CaCO₃ with uniform size distribution was successfully synthesized using continuous foam films as templates.2. The effect of gas velocity, concentration of foaming agent, sodium carbonate and calcium chloride concentration, as well as bubble size, and addition of polymer to the morphology and size of nano-CaCO₃ was investigated. The micro mechanism of controlling of size of nano-particles using the foam templates was discussed, which provide a direction for industrial production.