(178f) Elucidating the Electrokinetics in Diffusiophoresis in Porous Media

Diffusiophoresis is the deterministic motion of a colloid induced by a solute concentration gradient. The majority of diffusiophoresis studies has focused on colloids in a free electrolyte. A predictive model for diffusiophoresis in porous media is lacking. Here, a mathematical model is developed to compute the diffusiophoretic mobility of a colloid in porous media. We validate the model with experiments. We analyze how the physical properties of the colloid, the electrolyte, and the porous media affect the diffusiophoretic motion of the colloid. The present model can be employed to understand and predict diffusiophoresis in a wide range of applications, including colloidal species separation, nanoparticle drug delivery, and enhanced oil recovery.