Tailored Euler-Lagrange modelling of microfluidic solid/liquid reactive separations

Abstract

Micro- and nano- sized particles display an outstanding performance in the selective capture or release of molecules after the target species is contacted. Microfluidics can hugely benefit the performance of these systems given the remarkable features it presents. In this work, to the best knowledge of the authors, the microfluidic solid/liquid selective interfacial mass transfer is tackled for the first time in a Computational Fluid Dynamics (CFD) model based on the Euler-Lagrange framework. To gain insight on the effect of describing the particles as discrete entities, another model with the same purpose has been developed under the Euler-Euler approach. To experimentally validate and test the performance of the models, the microfluidic capture of chromate ions employing amino-functionalized particles in a Y-Y shaped microdevice has been selected as case study. Both models have been successfully validated, providing a relative root-mean-square error (RRMSE) of 9.86% for the Euler-Lagrange model and 22.62% for the Euler-Euler one. The performance of both models has been tested through a set of simulations in which the residence time and the load of particles are varied. The Euler-Euler option overestimates the hexavalent chromium removal in the kinetic region up to 27.94%, although both provide equally precise equilibrium data. The prediction difference between models is more significant when higher particle loads are used. Therefore, it is concluded that the Euler-Lagrange model proves to be a reliable and highly resourceful tool to predict the behavior of microfluidic multiphasic systems in a wide range of conditions.