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Published on: August 16, 2018
Fluorinated Covalent Organic Framework Membranes for Pervaporation Desalination
Jialei Hou1,2, Ziting Zhu1,2, Mengqi Bie1,2
1Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin300072, China.
ACS Nano
|August 11, 2026
Summary
Fluorinated covalent organic framework (COF) membranes offer advanced pervaporation desalination for high-salinity water. Fluorination enhances water transport and salt rejection by modifying nanochannel properties.
Area of Science:
- Materials Science
- Chemical Engineering
- Environmental Science
Background:
- Pervaporation membrane processes are promising for high-salinity water desalination.
- Developing advanced membrane materials and controlling water transport in nanochannels are key challenges.
Purpose of the Study:
- To develop novel fluorinated covalent organic framework (COF) membranes for efficient pervaporation desalination.
- To investigate the mechanism of fluorination-governed water transport and phase transition.
Main Methods:
- Assembly of COF nanosheets with tunable fluorine density to create membranes.
- Pervaporation experiments under varying salinity and temperature conditions.
- Experimental characterization and molecular simulations to elucidate transport mechanisms.
Main Results:
- Optimized fluorinated COF membranes achieved high water flux (435.75 kg m-2 h-1 at 3.5 wt% NaCl) and excellent salt rejection (>99.99%).
- Membranes maintained high performance under hypersalinity (176.38 kg m-2 h-1 at 15 wt% NaCl) and showed superior chlorine tolerance.
- Fluorination was found to disrupt water's hydrogen-bond network, facilitating evaporation and reducing transport resistance.
Conclusions:
- Fluorinated COF membranes show significant potential for high-performance pervaporation desalination.
- Fluorination facilitates phase-transition-coupled water transport by altering water structure and water-wall interactions.
- The study provides insights into designing membranes for efficient desalination through controlled nanochannel properties.
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