Rapid, in-line characterisation of a vortex mixer and its use for green synthesis of nanosilica

Abstract

Scaling-up nanomaterials synthesis is complex due to a lack of understanding of the effects of mixing and production scales on the process chemistry. The use of intensified mixers provide a way forward to address these challenges. To that end, this study represents a first step towards exploring the use of a vortex mixer to study the effects of mixing on the formation of nanosilica using a bioinspired green synthesis. Firstly, we designed a multi-inlet vortex mixer (MIVM) and characterised its mixing profile. To facilitate this process, enable faster measurements and address variability in the results, we designed and implemented an in-line measurement setup. The in-line setup was then used to characterise a vortex mixer and the results show excellent match between the custom-built setup and the traditional offline method, thus demonstrating its ability to provide a rapid and simple way for quantifying mixing. Finally, we explored the implementation of an MIVM for the green synthesis of silica for the first time. We observed that at higher flowrates when MIVM provides fast mixing, the conversion of the precursor, the yield and the product properties approached those of silica obtained from an ideally mixed batch system. Collectively, these results provide a clear pathway to help design future investigations to correlate the mixing conditions with emerging nanomaterials syntheses as well as enable their scale-up by implementing adequate mixing processes.