Toward numerical prototyping of labs-on-chip: modeling for liquid-liquid microfluidic devices for radionuclide extraction

Liquid-liquid extraction with stratified flows in a rectangular geometry is investigated in a double-Y shape glass chip. The velocity profiles are determined by a numerical method for two chemical systems: U(VI)/HCl/Aliquat(A (R)) 336 and Eu(III)/HNO3/DMDBTDMA. These results are compared with the theoretical results obtained from an analytical resolution described in a previous publication. The role of the viscosity difference between the two phases on the hydrodynamics is highlighted, as well as the influence of the geometrical cross section (symmetric and asymmetric channels). The numerical modeling of the mass transfer for the chemical system U(VI)/HCl/Aliquat(A (R)) 336 was then investigated, taking into account the results derived from the hydrodynamic modeling. Here, an interfacial reaction is assumed, and a global transfer coefficient is determined, enabling the concentration profiles for U(VI) in both the aqueous and organic phases to be obtained. Finally, the comparison between the experimental and theoretical results for different channel lengths allows for the validation of the mass transfer model, as well as a determination of the optimal extraction channel length.