Events

Presented by:

Dr. Menachem Elimelech
Yale School of Engineering and Applied Science

“Membranes for Selective Ion Separations at the Water-Energy Nexus”

Synthetic membranes are enabling components in key technologies at the water-energy nexus, including desalination, water purification, and energy conversion. Many applications at the water-energy nexus require ion selectivity, or separation of specific ionic species from similar species. Herein, we highlight how insights from nanofluidics and ion-selective biological channels establish the basis for a new class of membranes with ion-ion selectivity. We present a few examples demonstrating the paramount role of ion-membrane interactions in governing ion permeability and selectivity. First, we assess how ion–membrane binding energies affect the permeability of cations of similar size (copper, nickel, zinc, cobalt, and magnesium) through a multilayered polymer membrane. We observe that metals with higher binding energy to iminodiacetate groups of the polymer, which we determined via density functional theory calculations, selectively pass through the membrane in multi-salt solutions. Weaker binding species are precluded from partitioning into the polymer phase, which reduces their passage in proportion to their binding energy. Second, we report the ion permeability and selectivity of composite membranes comprising a selective thin film and a cation exchange membrane as the base layer. We characterize the separation performance of the composite membrane in electrodialysis showing that the polymer selective layer markedly increased the selectivity of the cation exchange membrane. We conclude with computational studies to further elucidate the roles of (i) pore mouth interactions versus intrapore interactions, (ii) spacing and arrangement of functional groups, and (iii) channel length in controlling ion-ion selectivity.

About the Speaker

Professor Elimelech received his B.S. and M.S. degrees from the Hebrew University of Jerusalem and his Ph.D. in Environmental Engineering from Johns Hopkins University in 1989. In 1998, he moved to Yale University to initiate their Environmental Engineering program. Professor Elimelech’s research is in the general area of the water-energy nexus. Specifically, the research in his group involves: (i) membrane-based processes for energy-efficient desalination and wastewater reuse, (ii) advanced materials for next-generation environmental separation and water decontamination technologies, and (iii) environmental applications of nanomaterials. Professor Elimelech has received numerous awards for his research, including the Clarke Prize for excellence in water research in 2005, the Eni Award for Protection of the Environment in 2015; election to the National Academy of Engineering in 2006, and election to the Chinese, Australian, and Canadian Academies of Engineering in 2017, 2021, and 2022, respectively.