Synthesis of Monodispersed SiO2 and TiO2 Nanoparticles using Semibatch Reactor and Comparison of Parameters Effecting Particle Size and Particle Size Distribution

Abstract

Monodisperse SiO2 and TiO2 nanoparticles were synthesized from tetraethyl orthosilicate (TEOS) and tetraethyl orthotitanate (TEOT) dissolved in ethanol, respectively, using a semibatch method which was found to be easier than a batch process in controlling the size, shape, and size distribution In this study, a statistical experimental method was also used to compare the properties (particle size and standard deviation) of the SiO2 and TiO2 particles according to four parameters [R(=H2O/TEOS or TEOT), hydroxypropylcellulose (HPC)/ NH3, the feed rate of the reactant, and the reaction temperature]; It was found that the optimal conditions for the preparation of SiO2 and TiO2 nanoparticles in a semibatch process were as follows.; (1) SiO2; R(=[H2O/TEOS]): 31, concentration of ammonia: 0.32 mole/1, feed rate of reactant: 17 ml/min, reaction temperature: 62 ℃, (2) TiO2; R(=[H2O/TEOT]): 16, HPC: 0.0028 g/ml, feed rate of reactant: 0.6 ml/min, reaction temperature: 30 ℃. Using the above optimal conditions, particles of SiO2 (13.7 nm) and TiO2 (10.6 nm) with a narrow size distribution were prepared. In addition, it was found that the main parameters affecting the preparation of SiO2 and TiO2 nanoparticles decreased in the order of the feed rate of the reactant > NH3/ HPC > R (=H2O/TEOT) > the reaction temperature.