1. Effective regulating interfacial polymerization process of OSN membrane via in-situ constructed nano-porous interlayer of 2D TpHz covalent organic frameworks.
- Author
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Li, Shuxuan, Yang, Fangyuan, Liu, Shaoxiao, Li, Honghai, Su, Baowei, Han, Lihui, Gao, Xueli, and Gao, Congjie
- Subjects
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ROSE bengal , *ORGANIC solvents , *MOLECULAR weights , *POLYMERIZATION , *RHODAMINE B , *COVALENT bonds , *POLYIMIDES - Abstract
In this study, a kind of thin film composite (TFC) membrane with two-dimensional (2D) covalent organic frameworks (COFs) as interlayer, termed as iTFC, which has integrally covalent bonding structure, ultra-thin and ultra-smooth surface, as well as high separation performance was fabricated via interfacial polymerization (IP) and subsequent chemical cross-linking and solvent activation for organic solvent nanofiltration (OSN). The COFs interlayer was in situ constructed using 1,3,5-triformylphloroglucinol (Tp) and hydrazine (Hz) on polyimide (PI) substrate prior to the IP. The optimization of the membrane fabrication process shows that very low concentration for both the COFs aqueous monomer Hz and the IP aqueous monomer m-phenylenediamine (MPD) was conducive to the formation of very smooth (roughness of 2.4 nm), very thin and defect-free cortex, thus improving the organic solvent permeation while remaining the dye rejection. Under optimal conditions, the prepared iTFC OSN membrane has an ethanol permeance of 63.4 L m−2 h−1 MPa−1, a Rhodamine B (RDB) rejection of greater than 99 %, and a molecular weight cut-off (MWCO) of as low as 380 Da. In addition, after filtration of 100 mg L−1 RB/DMF solution for 408 h, the optimized iTFC OSN membrane remained Rose Bengal (RB) rejection above 97 %, which proves its excellent solvent resistance performance. [Display omitted] • Ultra-low content Tp and Hz monomers are used for in situ construction of ultra-thin TpHz COFs interlayer. • Ultra-low content MPD, TMC monomer are used during the interfacial polymerization process. • Integrally covalent bonding forms between the adjacent layers of substrate, COFs interlayer and skin layer. • The iTFC OSN membrane achieves a much higher ethanol permeance of 63 L m−2 h−1 MPa−1 and 99 % high RDB rejection. • The integrally covalent bonding TFN OSN membrane achieves superior solvent resistance. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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