Enhancement of Mixing and Mass Transfer Performance with a Microstructure Minireactor for Controllable Preparation of CaCO₃ Nanoparticles

Abstract

CO2/Ca(OH)2 precipitation reaction was used to prepare CaCO3 nanoparticles in this work. As a fast reaction system, nice mixing and a fast mass transfer rate of CO2 are required to enhance supersaturation. To increase the mixing performance, a microstructure reactor, a membrane dispersion minireactor, which has microfiltration membranes as the dispersion media, was introduced and CaCO3 nanoparticles with average diameters ranging from 34.3 to 110 nm were prepared. Several operating conditions were investigated for the purpose of controlling the particle size. In addition, a deep analysis on the mass transfer flux density of CO2 was carried out and the particle size decreased with the increasing of the mass transfer flux density during the reaction. Compared with a membrane-free reactor, it was found that the mixing performance was significantly enhanced by the effect of the micropore membrane, and nanoparticles cannot be prepared without it.

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