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

Autor: D. Williamson, A. Montes, U. Teipel, E.J. Martínez de la Ossa, I. García-Casas, F. Hanke, C. Pereya
Rok vydání: 2018
Předmět:
Zdroj: The Journal of Supercritical Fluids. 133:218-224
ISSN: 0896-8446
DOI: 10.1016/j.supflu.2017.10.013
Popis: A supercritical anti-solvent (SAS) process was carried out to obtain micron and submicron particles (0.35–1.78 μm) of silica from a solution with a silica precursor. The effects of different parameters such as pressure (120 and 150 bar), temperature (323 and 333 K), CO 2 flow rate (20 and 35 g/min), liquid solution flow rate (4 and 8 mL/min) and nozzle diameter (0.1 and 0.2 μm) on the outcome of the SAS process were analyzed. The TEOS: water molar ratio (1:4–1:17) was also evaluated and seems to play a major role in the precipitation of particles, especially in terms of agglomeration and morphology in that a higher amount of water leads to lower agglomeration of particles. Higher CO 2 and lower liquid solution flow rates are recommended to obtain a smaller particle size with narrow particle size distribution (0.35 ± 0.17 μm). Lower temperatures are recommended to reduce the particle size. The rest of the assayed variables did not have a significant influence on particle size and size distribution. As far as the textural properties are concerned, silica particles with low porosity (1.41–10.22 m 2 /g) and certain hydrophilic character were generally produced.
Databáze: OpenAIRE
Externí odkaz: