In situ preparation of hydrophobic CaCO3 nanoparticles in a gas–liquid microdispersion process

Abstract This study presents a novel process of in situ surface modification of CaCO3 nanoparticles using a multiple-orifice dispersion microreactor. CO2/Ca(OH)2 precipitation reaction was employed to prepare CaCO3 nanoparticles with sodium stearate surfactant. Synthesized CaCO3 products were characterized by thermogravimetric analysis (TGA), infra-red (IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer–Emmet–Teller analysis (BET). The effect of various operation parameters on nanoparticles and the dosage of sodium stearate were determined. The results showed that the preparation process could be precisely controlled with efficient mass transfer process. The particles were highly hydrophobic with a contact angle of 117° and monodisperse with an average size of 30 nm. The adsorptions of sodium stearate and calcium ion on solid particles during the in situ surface modification process were investigated.