Synthesis of Ca(OH)2 nanoparticles from diols

The aim of this project was to study the preparation and characterization of nanosized Ca(OH)2 particles. Synthesis of Ca(OH)2 particles was performed at a high temperature, and diols were employed as the reaction media. The size and shape of the particles were found to be dependent on different experimental factors, such as reaction temperature, concentration of the reactants, molar ratio, and aging time. Several syntheses were carried out using different parameters. The higher solubility of Ca(OH)2 in diols than in water made the synthesis of the nanoparticles particularly difficult. The diols used (1,2-ethanediol and 1,2-propanediol) remained adsorbed onto the nanoparticles, which caused aggregation, forming micronsized agglomerates. Their removal, with subsequent dispersion of the nanosized units, was achieved by peptization with 2-propanol in an ultrasonic bath. The nanoparticles were characterized by X-ray diffraction analysis, transmission electron microscopy, and Fourier transform infrared spectroscopy. Short aging times produced very small particles sized ca. 30-60 nm. For all the other syntheses carried out, the particle size was in the range of 50-150 nm depending on the molar ratio of the reactants.