Related Experiment Video
Updated: Jan 22, 2026

Author Spotlight: Characterizing Porous Materials for Aiding the Development of Robust Metal-Organic Frameworks with Adsorption Behavior
Published on: March 8, 2024
Highly Selective Transport of Alkali Metal Ions by Nanochannels of Polyelectrolyte Threaded MIL-53 Metal Organic
Liang Gao1, Kwong-Yu Chan1, Chi-Ying Vanessa Li1
1Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , Hong Kong.
Abstract:
Conventional ion-exchange polymeric membranes have limited selectivity due to their nonuniform and unstable structures. The rigid, regular, high porosity of metal organic framework (MOF) generally provides MOF membrane with exclusion/sieving effect but lack of electrostatic screening. Here we report for the first time a nonbiological highly selective MOF membrane with polyelectrolyte threaded in the nanochannel of metal organic framework (polyelectrolyte∼MOF) and its selective transport of alkali metal cations. Poly(sodium vinyl sulfonated-co-acrylic acid)∼MIL-53(Al) is prepared on anodic aluminum oxide substrate via steps of MOF MIL-53(Al) growth followed by in situ polymerization. The poly(VS-co-AA)∼MIL-53(Al) membrane demonstrates highly specific selectivity in transport of alkali metal cations. Rate of ion transport correlates inversely with the hydrated diameter of the ion reaching a low limiting rate near 0.7 nm hydrated diameter. Charge exclusion is demonstrated with blockage of anion transport under a concentration gradient. The highly uniform porous nanostructure of MOF and ionic function of polyelectrolyte offers the MOF membrane with synergistic selectivity based on exclusion forces of the framework and Coulomb forces from fixed charges of polyelectrolytes in nanochannels.
Related Concept Videos
Alkali Metals
Table 1: Properties of the alkali metals
Bonding in Metals
Metal-Ligand Bonds
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
Metallic Solids
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....
Properties of Transition Metals
Ions and Ionic Charges

