Micelle-mediated separations provide gentle techniques that prevent molecules of the target biocomponent from decomposition or chemical change. In this work, we briefly discuss different molecular-thermodynamic tools for describing the partitioning of a biocomponent between the micellar aggregates and the surrounding solution, highlighting their advantages and limitations. We then focus on a recently proposed modification of the classical molecular-thermodynamic aggregation model that takes into account complex interactions within the micellar corona, including the hydrogen bonding with the hydration water. Taking n-octanol as a model biocomponent, we apply that model to describe the aggregation behavior and partitioning of octanol in solutions of nonionic surfactant Triton X-114 with added micelle-forming ionic liquid 1-methyl-3-octylimidazolium chloride. For this mixture, we report new experimental data on the cloud-point temperatures and partition coefficients of n-octanol. The data on octanol partitioning are used to test predictions from the model.