Dispersion‐free solvent extraction with microporous hollow‐fiber modules

Abstract

Abstract Extensive studies on dispersion‐free solvent extraction have been carried out using modules made with either hydrophobic or hydrophilic microporous hollow‐fiber membranes. Membrane and boundary layer resistances have been characterized for both kinds of hollow fiber using solvent extraction systems with a wide variation of distribution coefficients and interfacial tensions. It has been found that the Graetz solution for a constant wall concentration describes satisfactorily mass transfer on the lumen side of a hollow‐fiber device. A correlation of the form N Sh = [ D h (1 − ϕ)/ L ] N N appears to provide a close fit to the shell‐side mass transfer coefficient data. The perforamnce characteristics of dispersion‐free extraction in hollow‐fiber modules have been considered against those of commercial packed‐bed extractors. A perspective has been provided on comparative utilities of hydrophobic or hydrophilic hollow fibers for a given solvent extraction problem.