Effects of porous media on extraction kinetics: Is the membrane really a limiting factor?

Abstract : Porous media in extraction and especially pertraction are often suspected to add unnecessary diffusive resistance and considerably slow down extraction kinetics. This work presents a miniaturized pertraction device and simulation of diffusive and reactive solute transport. Kinetics are experimentally observed and numerically fitted. Reaction rates – or solute transfer rates – are estimated via this fit on a numerical basis. The work shows that the diffusive resistance created by a porous medium is prevalent only at low distribution coefficients. At high distribution coefficients as is the case of quasi all industrial processes, the porous membrane does not interfere with overall kinetics. Instead, the diffusive resistance is shared between the feed and extraction phases, and the interface transfer, depending on the value of the transfer rate. Overall, this work can be generalize as enabling the measurement of solute transfer rates at the liquid-liquid interface, a key parameter in pertraction and membrane separation which is difficult to measure using classic methods of extraction.