Ben Alessio ’21

Headshot of Ben Alessio


Project Title

Electrokinetics for Separation of Particles and Potential Water Purification

Presentation Link

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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.”

Internship Year


Project Category

Water and the Environment


Complex Fluids Group, Department of Mechanical and Aerospace Engineering, Princeton University


Howard Stone, Donald R. Dixon ’69 and Elizabeth W. Dixon Professor of Mechanical and Aerospace Engineering