Preparation of Vaterite Calcium Carbonate in the Form of Spherical Nano-size Particles with the Aid of Polycarboxylate Superplasticizer as a Capping Agent

Vaterite is an important biomedical material due to its properties such as high specific surface area, high solubility, high dispersion, and small specific gravity. In this study, spherical vaterite composed of nanoparticles are synthesized by precipitation route assisted by Polycarboxylate superplasticizer (PSS). The calcium carbonate was prepared by reacting a mixed solution of Na2CO3 with a CaCl2 solution at an ambient temperature, 25 °C, in the presence of polycarboxylate superplasticizer as a stabilizer. The effects of PSS on the morphology and polymorph of precipitated CaCO3 are investigated with the help of Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and X-ray diffraction (XRD) and Transmission electron microscopy (TEM). It is supposed that the core-shell structured microspheres with the nanoparticles are attributed to the adsorption of PSS on the faces of calcium carbonate crystals. The results revealed that polycarboxylate superplasticizer can use in preparation of vaterite calcium carbonate from aqueous solutions. The prepared vaterite calcium carbonate has nanoparticles with the average particle size ranging from 15 to 26 nm as estimated using TEM.