Homointerface covalent organic framework membranes for efficient desalination

Covalent organic frameworks (COFs) are an emergent class of crystalline porous polymers featuring a long-range regular pore structure, high porosity and excellent chemical stability. Bilayer COF membranes with tunable interfaces hold great promise in ionic and molecular separations. Herein, we desig...

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Bibliographic Details
Published in:Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2021-10, Vol.9 (4), p.23178-23187
Main Authors: Shen, Jianliang, Yuan, Jinqiu, Shi, Benbing, You, Xinda, Ding, Rui, Zhang, Tianyi, Zhang, Yujing, Deng, Yuanzhi, Guan, Jingyuan, Long, Mengying, Zheng, Yu, Zhang, Runnan, Wu, Hong, Jiang, Zhongyi
Format: Article
Language:English
Subjects:
Ambient temperature
Bilayers
Counterdiffusion
Desalination
Diffusion layers
Interface stability
Interfaces
Membranes
Polymers
Porosity
Rejection rate
Sodium sulfate
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Summary:Covalent organic frameworks (COFs) are an emergent class of crystalline porous polymers featuring a long-range regular pore structure, high porosity and excellent chemical stability. Bilayer COF membranes with tunable interfaces hold great promise in ionic and molecular separations. Herein, we designed a series of bilayer COF membranes with homointerface and heterointerface, which achieved efficient desalination performance through manipulating the interface confinement effect. COF membranes were prepared on a porous support through successively regulating the growth of imine-based 2D COF layers by in situ growth and counter-diffusion approach at ambient temperature. Narrowed sub-nanometer interlaced channels were created at the interface of the two adjacent COF layers. The rejection rate of homointerface COF membrane toward Na 2 SO 4 was higher than that of heterointerface COF membranes, which was due to the synergistic enhancement of interface-confined size sieving and Donnan effect. The homointerface TpPa-SO 3 H/TpPa-SO 3 H/MPAN membrane exhibits a rejection rate of 98.3% for Na 2 SO 4 and water flux of 13.1 L m −2 h −1 bar −1 , which is the highest performance among COF desalination membranes ever reported. Homointerface COF membrane with size and charge tunable channels exhibits superior salt rejection and high water flux performance.
ISSN:2050-7488
2050-7496
DOI:10.1039/d1ta06439h