Impact of Ligand Chemistry on Ion Selectivity in Unimolecular Channels

Critical element recovery from a variety of waste streams is a promising way to meet modern demand for lithium and lanthanide resources. The difficulty surrounding the purification of such ions is the similarity of lithium to common monovalent ions (potassium and sodium) and the similarity of lanthanides to each other. To effectively extract such similar ions with high selectivity and permeability, artificial water channels have been proposed to take advantage of small differences in the size of hydrated ions. One such way to tune the selectivity of these channels is by changing the appended-chemistry. From our previous findings, we propose that ligand chemistries which display effective solvent extraction potential detract from the single-ion selectivity within the channel. To probe this effect, we probe ligands across a range of distribution coefficients through molecular dynamics simulations and hope to narrow the scope of ligand candidates for unimolecular channel membranes.