(6il) Engineering Anisotropy a New Design Strategy for Membrane Gas Separations

Research Interests: My research lies at the interface of engineering, transport phenomena, and rational material design. Specifically I am developing new strategies to design novel materials to control mass diffusion processes, with a special emphasis on membrane separations.

Teaching Interests: One of the pillars in Chemical Engineering core-curriculum education is transport phenomena. This subject is often characterized by undergraduate students as difficult and abstract. My teaching goals are focused on designing new active learning strategies that allow a more engaging and effective introduction and study of heat, mass, and momentum transport processes.

The design of membrane materials for gas separations has primarily relied on tuning the membrane chemical properties with the aim of tailoring the permeability and selectivity for the compounds of interest. From a physical point of view, manipulating the permeability and selectivity allows controlling the flux magnitude of the species in a prescribed way. Although this approach has been extensively used to design membrane and separation systems, the possibility of controlling flux direction to perform separations has remained largely unexplored. In this work, we show how metamaterial theory and effective medium approaches can be used to design novel anisotropic membranes that can be exploited for membrane-based gas separations. The proposed membranes consist of multilayer systems made of isotropic materials in which rationally designed anisotropic diffusion is controlled by the structural arrangement of the constituent materials rather than their chemical composition. Our novel anisotropic membranes operate by directing molecules of different species toward different places in the permeate side. Separation occurs as a result of the rerouting of mass flux in addition to differences in solubility and diffusivity. In terms of efficiency, we show that the selectivity of anisotropic membranes can be increased by orders of magnitude in comparison with typical isotropic materials while retaining similar permeabilities. Our work paves the way for the development of a new approach to design membrane materials and separation processes by taking advantage of an often overlooked intrinsic property of mass flux, its directionality.