Ion sieving by a two-dimensional Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> alginate lamellar membrane with stable interlayer spacing.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32669687.
- Also identified by DOI 10.1038/s41467-020-17373-4 and PMC identifier 7363915.
- 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
Two-dimensional membranes attract extensive interest due to the anomalous transport phenomena; however, the ion separation performance is below the theoretical prediction. The stabilization of d-spacing is a key step for enhancing ion selectivity. Here, we demonstrate a strategy for stabilizing the Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> laminar architecture by alginate hydrogel pillars. After pillared by Ca-alginate, the nanochannel diameters are effectively fixed at 7.4 ± 0.2 Å, and the membrane presents a permeation cutoff and an outstanding sieving property towards valent cations. When applied for acid recovery, the outstanding H<sup>+</sup>/Fe<sup>2+</sup> selectivity makes the membrane a promising substitution for traditional ion-exchange membranes. Moreover, the ultrathin Mn-alginate pillared membrane with identical d-spacing exhibits 100% Na<sub>2</sub>SO<sub>4</sub> rejection with high water permeance, which is superior to the state-of-the-art nanofiltration membranes. Building on these findings, we demonstrate an efficient method to tune the ion selectivity and introduce a new perspective for energy- and environment-related applications.