(452g) Charged Polymer Membranes with Ion-Specific Chelating Groups for the Selective Recovery of Copper

Charged polymeric membranes are used in a variety of electrochemical applications. Increasingly, for applications such as resource recovery or contaminant removal, there is a need for charged membranes that can transport a specific ion or charged species of interest. One approach is to design membranes with ion-specific chelating groups that can bind more strongly to an ion or molecule of interest, but examples of these systems for specific removal of target ions remains limited. Here, we demonstrate a charged membrane with functional groups designed bind strongly to copper ions. Specifically, we prepare a series of charged polymer membranes containing iminodiacetic acid functional groups, ranging from 10 – 50 mol% of the backbone repeat units. By varying crosslink density, we can simultaneously control the final water content of the membranes, and we also explore the impact of microstructure by comparing the performance of membranes with homogeneously distributed chelating groups and surface-modified membranes. We demonstrate an optimal content of chelating groups and water content that provides selectivity towards copper and implement this material an electric-field driven separation process. We also demonstrate that microstructure has a significant impact on ion transport. This work elucidates design principles for charged polymer membranes containing chelating groups that bind to an ion of interest, and our findings will be useful for separations applications and other energy-relevant applications.