CFD Simulation of Chaotic Flow Characteristics in an Oscillating Feedback Microreactor and Its Application for Preparing Zeolitic Imidazolate Framework-8 Nanoparticles

A four-stage asymmetric oscillating feedback microreactor (FOFM) was developed to prepare high-quality zeolitic imidazolate framework-8 (ZIF-8) nanoparticles with high throughput. First, the chaotic flow characteristics of FOFM were investigated by CFD simulation, and the chaotic advection intensity was quantitatively characterized by different characteristic parameters, then the corresponding mathematical models between chaotic flow parameters and Reynolds number (Re) were constructed. Furthermore, the relationship between mixing efficiency and Re was established, indicating that mixing enhancement could be achieved at larger Re. Subsequently, based on FOFM, the morphology and size of ZIF-8 samples were adjusted by varying the experimental conditions. An average size of 255 nm with a narrow particle size distribution (geometric standard deviation of size: 1.11) was achieved at a throughput of 180 mL/min, and the largest space-time yield reached 4.15 × 106 kg m–3 day–1. The fabricated FOFM is apt for large-scale production of uniform ZIF-8 nanoparticles and other nanoparticles.