Related Experiment Video
Updated: Oct 9, 2025
08:06
Merging Ion Concentration Polarization between Juxtaposed Ion Exchange Membranes to Block the Propagation of the Polarization Zone
Published on: February 23, 2017
8.6K
Designing Angstrom-Scale Asymmetric MOF-on-MOF Cavities for High Monovalent Ion Selectivity
Mojtaba Abdollahzadeh1, Milton Chai2,3, Ehsan Hosseini4
1School of Engineering, Macquarie University, Sydney, NSW, 2109, Australia.
Advanced Materials (Deerfield Beach, Fla.)
|December 18, 2021
Summary
Researchers developed a novel membrane mimicking biological ion channels for efficient alkali metal ion separation. This breakthrough offers enhanced selectivity and ion current rectification for energy storage and sensing applications.
Area of Science:
- Materials Science
- Electrochemistry
- Nanotechnology
Background:
- Biological ion channels enable efficient alkali metal ion separation and sensing via angstrom-scale asymmetrical cavities.
- Efficient ionic separation is crucial for clean energy technologies and lithium-based energy storage.
- Replicating these sophisticated biological structures artificially presents significant challenges.
Purpose of the Study:
- To introduce a tunable design for fabricating monovalent ion-selective membranes with asymmetric sub-nanometer pores.
- To create artificial ion channels that mimic biological selectivity and transport efficiency.
- To investigate the underlying mechanisms of ion selectivity and rectification in engineered membranes.
Main Methods:
- Fabrication of a bilayer metal-organic framework (MOF-on-MOF) membrane with asymmetric sub-nanometer pores (6 to 3.4 angstroms).
- Incorporation of energy barriers within the pores to control ion movement.
- Ionic current measurements to assess selectivity and rectification ratios.
- Quantum mechanics/molecular mechanics (QM/MM) simulations to elucidate the mechanism of ion selectivity.
Main Results:
- The MOF-on-MOF membrane achieved an unprecedented ionic current rectification ratio exceeding 100.
- Exceptional selectivity ratios were observed: 84 for K+/Li+ and 80 for Na+/Li+.
- High ion flux was demonstrated, with 1.14 Li+ mol m-2 h-1.
- QM/MM simulations revealed that spatial hindrance and nucleophilic entrapment induce energy barriers, responsible for high selectivity and rectification.
Conclusions:
- The developed membrane design successfully replicates the function of biological ion channels for selective ion separation.
- The engineered energy barriers provide ultrahigh selectivity and ion rectification, crucial for advanced separation technologies.
- This work presents a significant advancement with broad implications for sensing, energy storage, and separation technologies.
Keywords:
asymmetric nanochannelion rectificationion-selective membranelithium recoverymetal-organic frameworksMore Related Videos
Related Concept Videos
01:17Ion Exchange
697
Ion exchange chromatography separates charged molecules from a solution by reversibly exchanging them with mobile, or 'active', ions associated with the oppositely charged stationary phase. This method can be used to separate ions, soften and deionize water, and purify solutions. The polymers comprising the ion-exchange column are high-molecular-weight and chemically stable polymers, crosslinked to be porous and essentially insoluble. They are also functionalized with either acidic or...
697
01:25MOS Capacitor
1.1K
A Metal-Oxide-Semiconductor (MOS) capacitor is a fundamental structure used extensively in semiconductor device technology, particularly in the fabrication of integrated circuits and MOSFETs (metal-oxide-semiconductor field-effect transistors). The MOS capacitor consists of three layers: a metal gate, a dielectric oxide, and a semiconductor substrate.
The metal gate is typically made from highly conductive materials such as aluminum or polysilicon. Beneath the metal gate lies a thin layer of...
The metal gate is typically made from highly conductive materials such as aluminum or polysilicon. Beneath the metal gate lies a thin layer of...
1.1K