SOL-GEL reactor with rapid micromixing, modelling and measurements of titanium oxide nano-particle growth.

Abstract

We present a concept of the sol–gel reactor with injection of stock solutions through a T mixer, environmental gas control, thermal control of the reactive medium and in–situ particle size measurement using a monomode optical fibre probe. The rapid injection of the whole amount of reagents leads to short time of nucleation, and the micro-mixer eliminates gradients of concentrations, which results in higher local nucleation and aggregation rates. The reactor is used for production of mono-disperse nanometric titanium oxide sols. With this reactor, induction kinetics are reproducible and agree with a model describing the mean particle size increase by a slow aggregation process. As well as the in–situ size measurement technique, the reactor is a kinetic tool for determination of the sol aggregation rate. As the rules for scale-up of its equipment are already established, it is of interest for the operation and the design of industrial-scale sol–gel reactors.