Experimental Methodology for Kinetic Acquisitions Using High Velocities in a Microfluidic Device

A theoretical description and an experimental validation of the application of a microfluidic chip with high‐velocity stratified flows for determining chemical kinetics for liquid‐liquid extraction are presented. In the case of uranium extraction under PUREX (plutonium and uranium refining by extraction) process conditions, a simple theoretical model demonstrates the need for high velocities and short residence times of around 10 ms. Confocal microscopy observations of the interface were undertaken to insure the flow stability at such high velocities, and the same experimental protocol was carried out to uranium(VI) extraction at two concentrations. Results show an unexpected variation in the phase homogenization depending on the uranium concentration of the extracted phase. The application of a microfluidic chip with high‐velocity stratified flows for determining chemical kinetics for liquid‐liquid extraction is theoretically and experimentally validated. A simple theoretical model shows the need for short residence times involving high fluid velocities. Confocal microscopy proves that with such parameters no major deformation of the liquid‐liquid interface occurs.