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

Abstract

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.

Liquid/Liquid Extraction Kinetics of Eu(III) and Am(III) by Extractants Designed for the Industrial Reprocessing of Nuclear Wastes

“…34 However, it is not easy to reliably control the flow and the transport of the species in cells in which the interface is free. It still seems difficult to estimate the contribution from diffusional transport in these cells without making some approximations, in the case of parallel flows 35 (in which the geometries are not yet simple enough to allow an estimation of the diffusional contribution) as well as moving droplets. 36,37 As a consequence, these studies generally deliver values for global (apparent) kinetic rate constants combining the effect of the interfacial reaction and diffusional transport in the layers adjacent to the interface.…”

A microfluidic study of synergic liquid–liquid extraction of rare earth elements

“…Hence, it enables the quantification of extraction kinetics and interfacial mass transfer rate constants, otherwise fairly difficult to quantify. More specifically, advantages of the microfluidic platform used in this article are: (i) a large range of contact time can be investigated (which is not the case when the two phases are directly brought into contact in a co-flow microchannel); 27,31,62,63 (ii) the assembly of the cell and technology required are simple and do not need complex handling/building procedures or expansive process controls such as what is required when using alternating phase droplets. 22 Hence, it should be noted that our simple design and assembly method, using only four screws to hold in place and squeeze the membrane, proved to be very efficient and therefore economical as it enabled us to perform all seventy-five microfluidic extraction experiments, including fifteen membrane exchanges, without any disabling leaking issue.…”

“…In order to reduce time and volume, relying on microfluidic devices represents a very promising route. 15,[22][23][24][25][26][27][28][29][30][31] Indeed, since the pioneering work of Ismagilov and co-workers, 22 microfluidics has been developed as a popular method to save quantities of test materials needed to complete experimental plans in formulating efficient processes. The main difficulties in using microfluidics instead of the old ''batch'' method are related to the adsorption of electrolytes on all interfaces present and to the sensitivity required in elemental analysis.…”

Microfluidic lab-on-chip advances for liquid–liquid extraction process studies

“…Such devices can now be found commercially and have recently been used for the study of liquidliquid extraction (which used Y-Y geometry glass microchips from Dolomite® [12,13].…”