Synthesis of nanosized BaSO4 and CaCO3 particles with a membrane reactor: effects of additives on particles

Nanosized BaSO(4) particles, about 15 nm in size, were synthesized successfully by a membrane reactor at the aids of additives, in which Na(2)SO(4) solutions were added into BaCl(2) solutions gradually through the micropores of ultrafiltration membranes to control the saturation ratio, subsequently the nucleation and growth rates. The effects of additives species, additives concentrations, and membranes molecular weight cut-off (MWCO) on the particle morphology, along with the formation processes of particles, were investigated. CaCO(3) nanoparticles of 30-60 nm in size were also prepared by the reactor. The results revealed that the addition of methyl alcohol, ethanol etc. favor the synthesis of nanoparticles with small size. The particles size decreases with the increase in ethanol concentrations. With the increase in membrane MWCO, the products tend from nanoparticles towards aggregates.