Morphology-Controlled CaCO_3 Nanostructures by Modified Co-Precipitation in Pulsed Mode

摘要

Calcium carbonate nanoparticles and nanorods were synthesized by precipitation from saturated sodium carbonate and calcium nitrate aqueous solutions through co precipitation method. A new root of synthesis was done by both using pulsed mixing method and control of addition of calcium nitrate. The effect of the agitation speed, and the temperature on particle size and morphology were investigated. Particles were characterized using X-ray microanalysis, X-ray analysis (XRD) and scanning electron microscopy (SEM). The results indicated that increasing the mixer rotation speed from 3425 to 15900 rpm facilitates decreasing the average particle size to 64±7nm. A rapid nucleation then aggregation induced by excessive shear forces phenomena could explain this observation. Moreover, by increasing the reaction temperature, the products were converted from nanoparticle to nanorods. The maximum attainable aspect ratio was 6.23 at temperature of 75°C and rotation speed of 3425. Generally, temperature raise promoted a significant homoepitaxial growth in one direction toward the formation of calcite nanorods. Overall, this study can open new avenue to control the morphology of the calcium carbonate nanostructures.