New insights into the formation of submicron silica particles using CO2 as anti-solvent

Abstract

A supercritical anti-solvent (SAS) process was carried out to obtain silica submicron particles from a solution with a silica precursor. The effects of different parameters on the outcome of the SAS process were analyzed. The initial molar ratio of the injected solution seems to play a major role in the precipitation of particles, especially in consideration of agglomeration and morphology so higher amount of water lower agglomeration of particles. Higher CO2 and lower liquid solution flow rates are recommended to obtain smaller particle size with narrow particle size distribution. Lower level of assayed temperature is recommended to reduce the particle size. The rest of assayed variables did not have a significative influence on particle size and size distribution. According to the textural properties results, in general a little porous silica with certain hydrophilic character were produced.