A general diffusion model for mass transfer in colloidal liquid aphron systems

A general diffusion model for solute transport in colloidal liquid aphron (CLA) systems is proposed in terms of diffusive mass transfer. The model incorporates five specific mass transfer resistances occurred at interfaces and in liquid phases. The experimental cases conducted in CLA systems are simulated successfully to verify the validity of numerical procedure and underlying assumptions. Both numerical results and experimental data show that apparent diffusion coefficient of CLA systems is far smaller than that in pure solvent systems. This can be well explained considering the role of surfactants, which cause the interfacial resistance and micelles (or reverse micelles) hindrance. The interfacial resistances of adsorbed surfactants and formed micelles (or reverse micelles) hindrance are estimated by the simplex method from the experimental data. It is shown that both interfacial transfer coefficient and micellar diffusion coefficient decrease with the increase of surfactants concentration.