Ultrafast ion sieving using nanoporous polymeric membranes.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29422511.
- Also identified by DOI 10.1038/s41467-018-02941-6 and PMC identifier 5805712.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The great potential of nanoporous membranes for water filtration and chemical separation has been challenged by the trade-off between selectivity and permeability. Here we report on nanoporous polymer membranes with an excellent balance between selectivity and permeability of ions. Our membranes are fabricated by irradiating 2-μm-thick polyethylene terephthalate Lumirror® films with GeV heavy ions followed by ultraviolet exposure. These membranes show a high transport rate of K<sup>+</sup> ions of up to 14 mol h<sup>-1</sup> m<sup>-2</sup> and a selectivity of alkali metal ions over heavy metal ions of >500. Combining transport experiments and molecular dynamics simulations with a polymeric nanopore model, we demonstrate that the high permeability is attributable to the presence of nanopores with a radius of ~0.5 nm and a density of up to 5 × 10<sup>10</sup> cm<sup>-2</sup>, and the selectivity is ascribed to the interaction between the partially dehydrated ions and the negatively charged nanopore wall.