Our review paper titled “Advancing ion-exchange membranes to ion-selective membranes: principles, status, and opportunities” has been published in Frontiers of Environmental Science & Engineering as part of the Special Column—Young Talents collection.
Ion-exchange membranes (IEMs) are utilized in numerous established, emergent, and emerging applications for water, energy, and the environment. This article reviews the five different types of IEM selectivity, namely charge, valence, specific ion, ion/solvent, and ion/uncharged solute selectivities. Technological pathways to advance the selectivities are analyzed, and innovations in material and membrane design are specifically highlighted as prospective approaches to depart from the permeability-selectivity tradeoff by utilizing ion discrimination mechanisms that are radically different from current conventional membranes. We identify some of the gaps in fundamental understanding of the transport phenomena that are hindering the informed development of more ion-selective membranes.
