Monovalent anion-selective membranes fabricated via in situ interfacial polymerization.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41087365.
- Also identified by DOI 10.1038/s41467-025-64196-2 and PMC identifier 12521509.
- 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
Developing monovalent anion-selective membranes (MAPMs) faces challenges, including the trade-off between flux and selectivity, membrane stability, and cost-effective fabrication. Overcoming these requires advanced material design and scalable techniques. Here, we introduce in situ interfacial polymerization (ISIP) to prepare MAPMs. Base membranes are synthesized via superacid polymerization and modified with anion channels and -NH<sub>2</sub> groups. During ISIP, trimesoyl chloride reacts with surface -NH<sub>2</sub> groups, forming a partially crosslinked structure with -COOH groups to regulate ion transport via electrostatic interactions. This results in low membrane resistance (4.7 Ω cm<sup>2</sup>) and selective transport of weakly hydrated ions (Cl<sup>-</sup>, Br<sup>-</sup>, NO<sub>3</sub><sup>-</sup>), while strongly hydrated ions (SO<sub>4</sub><sup>2</sup><sup>-</sup>, F<sup>-</sup>) face higher barriers. MAPMs demonstrate high performance, achieving a limiting current density (>90 mA cm<sup>-</sup><sup>2</sup>), Cl<sup>-</sup> flux (1.98 mol m<sup>-</sup><sup>2</sup> h<sup>-</sup><sup>1</sup> at 5 mA cm<sup>-</sup><sup>2</sup>), and selectivity (244 for Cl<sup>-</sup>/SO<sub>4</sub><sup>2</sup><sup>-</sup>), confirming effective hydration dynamics control and balanced performance. Simulations reveal how charge distribution affects ion migration pathways.