Fast Desalination by Multilayered Covalent Organic Framework (COF) Nanosheets
Wei Zhou1, Mingjie Wei1, Xin Zhang1
1State Key Laboratory of Materials-Oriented Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, and College of Chemical Engineering , Nanjing Tech University , Nanjing 211816 , Jiangsu , P. R. China.
ACS Applied Materials & Interfaces
|April 11, 2019
Summary
Atomically thin covalent organic frameworks (COFs) show promise for water desalination. Stacking these COF layers, particularly in an offset eclipsed fashion, enhances ion rejection while maintaining high water permeance for efficient membrane performance.
Area of Science:
- Materials Science
- Nanotechnology
- Chemical Engineering
Background:
- Covalent organic frameworks (COFs) possess ordered nanopores ideal for separations.
- TpPa-1 COFs are promising for molecular sieving membranes due to their stability.
- Atomically thin TpPa-1 monolayers offer high water permeance but poor ion rejection.
Purpose of the Study:
- Investigate water and ion transport through multilayered TpPa-1 COFs.
- Determine the impact of stacking number and fashion on membrane performance.
- Explore rational design strategies for COF-based desalination membranes.
Main Methods:
- Nonequilibrium molecular dynamics simulations were employed.
- Analysis of interfacial and interior resistance for water transport.
- Systematic variation of COF monolayer stacking number and fashion.
Main Results:
- Increased stacking number enhances ion rejection at the cost of water permeance.
- Offset eclipsed stacking reduces effective pore size to 0.89 nm, boosting ion rejection.
- 25 stacked TpPa-1 monolayers achieved 100% MgCl2 rejection with superior water permeance.
Conclusions:
- Tailoring COF stacking number and fashion is crucial for designing high-performance desalination membranes.
- Multilayered TpPa-1 COFs offer a promising route to fast and efficient water purification.
- This study provides a rational design approach for advanced COF-based separation technologies.
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