Ultrathin and high-performance covalent organic frameworks composite membranes generated by oligomer triggered interfacial polymerization

• Published in: Journal of membrane science 2022-05, Vol.650, p.120431, Article 120431
• Main Authors: Lei, Ran, Zha, Zhiyuan, Hao, Zhan, Wang, Jixiao, Wang, Zhi, Zhao, Song
• Format: Article
• Language: English
• Subjects: COFs composite membranes; Dye rejection; Oligomer; Oligomer triggered interfacial polymerization; Permeability
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2022.120431

The practical application of covalent organic frameworks (COFs) membrane still faces major challenges emanated from harsh fabrication condition, non-uniform performance and high production cost. To address these issues, oligomer triggered interfacial polymerization (OT-IP) was proposed to fabricate COFs/PSf composite membranes, in which two reactive monomers having extremely low concentration (0.6 mM) were in advance pre-mixed in n-hexane to generate oligomers with planar structure, which was then subsequently grew under the catalysis of acetic acid to form an ultrathin and continuous COFs layer. The as-prepared TpPa/PSf (OT-IP), TpBd/PSf (OT-IP) and TpDp/PSf (OT-IP) composite membranes exhibited superior permeability of 52–85 L·m−2·h−1·bar−1 and congo red rejection of 93–99%, precisely in consistent with the pore sizes of COFs. The OT-IP technique would not only inspire the fabrication of COFs/PSf composite membranes with a greater variety but also make their scale-up and application feasible and economical. [Display omitted] •COFs composite membrane fabricated by oligomer triggered interfacial polymerization.•Spontaneous formation of oligomers by pre-mixing Tp and Pa into an organic solvent.•Ultrathin and regular COFs selective layer directly formed onto polymeric substrate.•High-performance COFs/PSf (OT-IP) membranes fabricated with TpPa, TpBd and TpDp.•Great reduction of membrane product costs due to low-concentrated monomer in OT-IP.