A high‐throughput chaotic advection microreactor for preparation of uniform and aggregated barium sulfate nanoparticles

Abstract

A high-throughput (105.5 g/h) passive four-stage asymmetric oscillating feedback microreactor using chaotic mixing mechanism was developed to prepare aggregated Barium sulfate (BaSO 4 ) particles of high primary nanoparticle size uniformity. Threedimensional unsteady simulations showed that chaotic mixing could be induced by three unique secondary flows (i.e., vortex, recirculation, and oscillation), and the fluid oscillation mechanism was examined in detail. Simulations and Villermaux-Dushman experiments indicate that almost complete mixing down to molecular level can be achieved and the prepared BaSO 4 nanoparticles were with narrow primary particle size distribution (PSD) having geometric standard deviation, σ g , less than 1.43 when the total volumetric flow rate Q total was larger than 10 ml/min. By selecting Q total and reactant concentrations, average primary particle size can be controlled from 23 to 109 nm as determined by microscopy. An average size of 26 nm with narrow primary PSD (σ g = 1.22) could be achieved at Q total of 160 ml/min.

Structure Screening of Oscillating Feedback Microreactors for the High-Throughput Synthesis of Zeolitic Imidazolate Framework-67 Nanoparticles with Controlled Size and Morphology

“…In addition, the three unique secondary flows (i.e., vortex, feedback, oscillation) can effectively induce chaotic advection, causing the fluids to stretch, fold, and compress, significantly shortening the molecule diffusion distance and improving fluid mixing and mass/heat transfer. − Hence, homogeneous concentration and temperature fields could be achieved in OFMs for preparing high-quality nanoparticles with a narrow PSD at high throughput. Lately, we demonstrated that OFMs could be applied for high-throughput production of inorganic nanoparticles, − where small samples with narrow PSD could be effectively prepared. However, OFMs have never been used to prepare ZIF-67 or other metal–organic framework materials.…”

“…In contrast to the ordered microreactors, it was disclosed that oscillating feedback microreactors (OFMs) based on chaotic advection can operate at high Reynolds numbers (i.e., high throughput, at Reynolds numbers of 10 2 –10 3 ), which is much larger than those of the ordered lamination flow and segmented flow microreactors (i.e., at Reynolds numbers of 10 –1 –10 2 ) . In addition, the three unique secondary flows (i.e., vortex, feedback, oscillation) can effectively induce chaotic advection, causing the fluids to stretch, fold, and compress, significantly shortening the molecule diffusion distance and improving fluid mixing and mass/heat transfer. − Hence, homogeneous concentration and temperature fields could be achieved in OFMs for preparing high-quality nanoparticles with a narrow PSD at high throughput. Lately, we demonstrated that OFMs could be applied for high-throughput production of inorganic nanoparticles, − where small samples with narrow PSD could be effectively prepared.…”