Designing Polymeric Membranes for High-Precision Ion Separations
Abstract
Synthetic polymer membranes are critical in energy production and water treatment technologies such as electrolyzers, flow batteries, and electrodialysis, but polymeric membranes cannot attain the highly precise ion separations needed for emerging applications of these technologies. Polymeric membranes have limited selectivity between ionic species of similar physicochemical characteristics because of their imprecise and nonuniform pore architecture and chemistry at the sub-nanometer scale. To leverage polymeric materials for challenging ion separations, selective coordination sites may be needed within a membrane to provide molecular recognition. However, the effects of coordinative interactions on membrane performance (permeability and selectivity) are poorly understood, which leaves little guidance for designing membranes with coordination chemistry.
In this talk, I will present how coordinative ion–membrane interactions affect permeability of similarly sized cations through a multilayered polymer membrane. I will show that a competitive binding (sorption) mechanism allows metals with higher binding energy to more selectivity permeate the membrane than weaker binding species, which promotes higher selectivities for ultrathin membranes than thicker ion-exchange membranes. While ultrathin membranes are key for selectivity, I will also discuss how introducing a thin selective layer to an underlying ion-exchange membrane only provides limited improvement in separation performance. Finally, I will propose how membrane design, including tailoring interactions between species of interest and an ultrathin selective layer, may lead to high precision and continuous ion-separation processes with polymeric membranes.
Biography
Ryan DuChanois is a Ph.D. Candidate and Abel Wolman Fellow in the Department of Chemical and Environmental Engineering at Yale University under the supervision of Professor Menachem (Meny) Elimelech. Ryan received a B.S. in Civil Engineering from the University of Arkansas summa cum laude and was the top graduate in the College of Engineering. Ryan also was a Gates Cambridge Scholar at the University of Cambridge, where he completed an MPhil in Engineering for Sustainable Development and received the Water Conservators Best Dissertation Prize. Now at Yale, Ryan takes inspiration from biological channels and seeks to develop a synthetic, ion-selective membrane able to selectively recover valuable resources from water.
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https://imperial-ac-uk.zoom.us/j/99265862892?pwd=YzVKZlhEY05rM1M0djFoSWJYOG8xQT09
Meeting ID: 992 6586 2892
Passcode: Water@2022