One step precipitation of CaCO3 nanoparticles assisted by drying and hydrothermal method

Abstract

Calcium Carbonate (CaCO3) is one of the most abundant natural resource exists. Precipitation is the most famous bottom up approach to synthesize CaCO3. This work explained preparation of (CaCO3) by unfiltered precipitation method and further dried by different methods. Different drying methods were executed post-precipitation step; normal drying and hydrothermal. Precipitated CaCO3 dried by normal drying managed to eliminate all Nitrogen (N) whereas drying by hydrothermal method still has traces of N left. The polymorphs of the synthesized CaCO3 are mostly calcite with traces of vaterite present. Normal drying method produced smaller CaCO3 crystallite size of 64.9nm compared to hydrothermal drying method synthesized CaCO3 with crystallite size 93.2nm. Annealing temperature is inversely proportional to the crystallite size of the treated CaCO3. Smallest crystallite size of synthesized CaCO3 is 25.5nm dried by normal drying method at 500°C. To the best of our knowledge, this is the first report of unfiltered precipitation and also the first to report on polymorph and crystallite size of CaCO3 synthesized by different drying methods.