Transport mechanisms in the micellar solubilization of alkanes in oil-in-water emulsions

The theory governing mass transfer rates associated with moving a solute from an oil droplet into an aqueous micellar solution is discussed. This theory is used to determine critical dimensionless groups that characterize transfer mechanisms, and to obtain rate equations for several limiting cases. These theoretical results are compared with experimental measurements of emulsified alkane solubilization into nonionic and anionic micellar solutions, with varying levels of convection and values of the aqueous phase viscosity. We conclude that two mechanisms are consistent with our observations: a molecular diffusive mechanism coupled with fast, irreversible reaction as proposed by (Kabalnov and Weers, Langmuir 12 (1996) 3442), or an interfacially controlled mechanism. The ability to understand and control these kinetic mechanisms is important in such processes as flavor and drug release, surfactant-based environmental remediation, detergency, multiphase chemical reactions, emulsion stability and in vivo digestion.