Electro-controlled angstrom-scale membrane channels and ion dehydration for tunable ion and molecule separations
Article
Zhang, H, Li, Q, Dong, X et al. (2026). Electro-controlled angstrom-scale membrane channels and ion dehydration for tunable ion and molecule separations
. WATER RESEARCH, 306 10.1016/j.watres.2026.126612
Zhang, H, Li, Q, Dong, X et al. (2026). Electro-controlled angstrom-scale membrane channels and ion dehydration for tunable ion and molecule separations
. WATER RESEARCH, 306 10.1016/j.watres.2026.126612
Membranes with tunable, selective separation properties are promising candidates for complex water/wastewater treatment and sustainable resource recovery. However, conventional membranes with fixed structures lack pore/channel adjustability and separation adaptability, making it extremely challenging to achieve angstrom-scale tunable and selective separation. Here, we report an electro-controlled MXene@polyaniline-poly(styrenesulfonate) membrane that enables precise regulation of angstrom‑scale channels and ionic dehydration, thereby achieving selective separations of mono- and di-valent salts and organic molecules. Applying a negative bias (0 − 2.5 V, membrane cathode) induces Na+ to undergo dehydration and embed into the polyaniline network, causing polymer chain deformation and enabling tunable membrane channel size between 5.6 Å and 10.3 Å. This electro-regulation endows the membrane with permeation selectivities of 30.4 for NaCl/Na2SO4 and 216−904 for salt/dye and salt/antibiotic, while their retention selectivities reach 196−312, significantly outperforming previously reported membranes. Theoretical calculations and simulations reveal that NaCl/Na2SO4 separation arises primarily from the preferential dehydration and permeation of Cl− over SO42− at a pore size of 7.1 Å (1.5 V). In contrast, salt/molecule separation relies on molecular steric hindrance to retain large molecules and ionic dehydration to permit salt permeation at a larger pore size of 10.3 Å (2.5 V). This study provides new insights for the development of smart membranes for fine separation and resource-based water treatment.
