Aqueous Two-Phase Interfacial Assembly of COF Membranes for Water Desalination

Hongjian Wang; Jiashuai Zhao; Yang Li; Yu Cao; Ziting Zhu; Meidi Wang; Runnan Zhang; Fusheng Pan; Zhongyi Jiang

doi:10.1007/s40820-022-00968-5

Aqueous Two-Phase Interfacial Assembly of COF Membranes for Water Desalination

Nanomicro Lett. 2022 Nov 9;14(1):216. doi: 10.1007/s40820-022-00968-5.

Authors

Hongjian Wang^#^{1

2}, Jiashuai Zhao^#^{1

2}, Yang Li³, Yu Cao^{1

2}, Ziting Zhu^{1

2}, Meidi Wang^{1

2}, Runnan Zhang^{1

2

4}, Fusheng Pan^{5

6

7}, Zhongyi Jiang^{8

9

10}

Affiliations

¹ Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China.
² Haihe Laboratory of Sustainable Chemical Transformations, Tianjin, 300192, People's Republic of China.
³ Department of Chemistry, Tianjin Key Laboratory of Molecular Optoelectronic Science, Tianjin University, Tianjin, 300072, People's Republic of China.
⁴ Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University Binhai New City, Fuzhou, 350207, People's Republic of China.
⁵ Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China. fspan@tju.edu.cn.
⁶ Haihe Laboratory of Sustainable Chemical Transformations, Tianjin, 300192, People's Republic of China. fspan@tju.edu.cn.
⁷ Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University Binhai New City, Fuzhou, 350207, People's Republic of China. fspan@tju.edu.cn.
⁸ Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China. zhyjiang@tju.edu.cn.
⁹ Haihe Laboratory of Sustainable Chemical Transformations, Tianjin, 300192, People's Republic of China. zhyjiang@tju.edu.cn.
¹⁰ Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University Binhai New City, Fuzhou, 350207, People's Republic of China. zhyjiang@tju.edu.cn.

^# Contributed equally.

Abstract

Aqueous two-phase system features with ultralow interfacial tension and thick interfacial region, affording unique confined space for membrane assembly. Here, for the first time, an aqueous two-phase interfacial assembly method is proposed to fabricate covalent organic framework (COF) membranes. The aqueous solution containing polyethylene glycol and dextran undergoes segregated phase separation into two water-rich phases. By respectively distributing aldehyde and amine monomers into two aqueous phases, a series of COF membranes are fabricated at water-water interface. The resultant membranes exhibit high NaCl rejection of 93.0-93.6% and water permeance reaching 1.7-3.7 L m^-2 h^-1 bar^-1, superior to most water desalination membranes. Interestingly, the interfacial tension is found to have pronounced effect on membrane structures. The appropriate interfacial tension range (0.1-1.0 mN m^-1) leads to the tight and intact COF membranes. Furthermore, the method is extended to the fabrication of other COF and metal-organic polymer membranes. This work is the first exploitation of fabricating membranes in all-aqueous system, confering a green and generic method for advanced membrane manufacturing.

Keywords: Aqueous two-phase; Covalent organic framework membranes; Interfacial polymerization; Molecular separation; Water desalination.