In-situ growth of olefin-linked covalent organic framework nanofiber membranes via surface-mediated condensation for sustainable removal of bisphenol A.

Developing multifunctional adsorbents with exceptional capture performance and outstanding stability is significant for pollutant removal. Olefin-linked sp² carbon-conjugated covalent organic frameworks (sp²c-COFs) exhibit high chemical stability and robust framework properties. This work developed a facile in-situ growth strategy to synthesize sp²c-COF films on polyacrylonitrile (PAN) nanofibers via aldol condensation. The abundant nucleation sites on the surface of functionalized PAN nanofibers (APAN) facilitated the synthesis of sp²c-COF nanofibers (APAN@TMT-TFPT) through a surface-mediated condensation reaction between 2,4,6-trimethyl-1,3,5-triazine (TMT) and 1,3,5-tris(4-formylphenyl) triazine (TFPT). APAN@TMT-TFPT exhibited a high specific surface area, porosity, and exceptional chemical stability, rendering it a highly promising adsorbent for aqueous environments. APAN@TMT-TFPT demonstrated exceptional adsorption performance for bisphenol A (BPA), and the adsorption behavior conformed to the Langmuir model, with a maximum adsorption capacity of 284.98 mg g. The abundant benzene rings and triazine units in APAN@TMT-TFPT provide numerous active sites for BPA interaction, while the robust sp²c-COF framework and macroscopic membrane structure ensure excellent reusability and recyclability. Notably, the in-situ growth of COFs on nanofibers proposed in this work can be extended to construct other highly stable sp²c-COF-based nanofiber membranes.