Ben Alessio ’21, Physics

I researched diffusiophoresis, which is the transport of charged colloids — mixtures of microscopic particles of one substance suspended in another — by a concentration gradient in a solution. Diffusiophoresis has been demonstrated to serve as a mechanism to aid water-purification processes, though it has numerous potential applications in the field of fluid mechanics. I focused on the numerical modeling of pore-geometry experiments in which diffusiophoresis forced the compaction or ejection of colloids from a small pore. I expanded the numerical model to include theorized physical effects that had been previously neglected, including constant colloidal charge, two-dimensional fluid-velocity field arising from solute-wall interactions, and multiple solutes with co-dependent electro-neutrality. With these effects in the numerical model, the predicted transport closely matched experiments being performed by the research group. Throughout this internship, I came to understand the importance of numerical modeling and the patience required for it. As a physics major, I was initially out of my comfort zone working on a chemical engineering problem. However, my experience with partial differential equations and coding helped guide me toward a productive and fulfilling research experience, which I will be continuing for my senior thesis.

* This internship is connected to the HMEI Water and the Environment Grand Challenges project, “Diffusiophoresis of Control of Particles in Water Systems.”