Gkogkos, Georgios; (2023) Investigation of miniaturised flow reactors for the continuous production of functional nanomaterials. Doctoral thesis (Ph.D), UCL (University College London).

Preview

Text Gkogkos_PhD_Thesis_2023_Fin.pdf - Accepted Version Download (15MB) | Preview

Abstract

Nanoparticle production using continuous flow miniaturised reactors is a promising alternative to conventional batch synthesis, but its application is limited by the challenging fabrication and relatively low throughput of miniaturised flow devices, as well as fouling. This thesis describes the development of nanoparticle production processes via miniaturised continuous flow reactors, taking into account these challenges. A specially designed millifluidic hydrodynamic flow focusing reactor was developed to enable continuous production of iron oxide nanoparticles via a rapid co-precipitation reaction, without fouling at the initial mixing point. For a higher (20x) nanoparticle production throughput compared to the millifluidic system, an impinging jet reactor was combined with a miniaturised CSTR cascade in a compact, vertical configuration, focusing on modularity and scalability. This reactor combination was 3D printed and used for continuous synthesis of high-quality iron oxide and silver nanoparticles, also demonstrating excellent fouling resistance. The hydrodynamics of the miniaturised CSTR were further investigated via computational fluid dynamics analysis revealing some operability limits in terms of throughput and active stirring speed. Considering these results, a miniaturised CSTR cascade, modified to accommodate reactants additions and mixing without the impinging jet, was used to for the synthesis of iron oxide nanoparticles at significantly increased throughput compared to the previous systems, helping to better identify the system limitations. Finally, the study of polydopamine formation rate as a function of oxygen concentration and temperature, enabled a continuous intensified process for polydopamine based nanoparticle synthesis via direct dopamine oxidation in a membrane capillary reactor assembled from commercially available parts. A non-ionic surfactant additive facilitated fouling resistance of the continuous flow system despite the adhesiveness of polydopamine, underlining the importance of particle wall interactions during continuous process design for nanomaterial synthesis.

Download activity - last month

Export as JSONXMLCSV

Download activity - last 12 months

Export as XMLCSVJSON

Downloads by country - last 12 months

Export as JSONXMLCSV

Archive Staff Only

View Item