Room-Temperature Synthesis Strategy for Constructing PSA-COFs Core–Shell Structured Fibers for Methylene Blue Dye Adsorption

Covalent organic framework materials (COFs) are promising for pollutant adsorption owing to their high specific surface area, tunable pores and functional designability, but their microcrystalline powder form leads to poor mechanical strength and processability, limiting practical applications. This study presents a mild, eco-friendly strategy using polysulfonamide fiber (PSA) with excellent mechanical and thermal stability as the core matrix, and room-temperature-synthesized sulfonic acid-functionalized TFP-DABA-COFs as the shell layer. Via coaxial wet spinning, core–shell structured PSA-COF composite fibers were fabricated without harsh solvothermal conditions, improving COF dispersion and interfacial bonding. Characterizations revealed the fibers possessed favorable comprehensive properties: fracture strength of 14.97 MPa, elongation at break of 32.84%, specific surface area of 8 m2/g, and hierarchical porous structures dominated by micropores, with enhanced hydrophilicity beneficial to aqueous adsorption. Adsorption experiments on woven fabrics showed 93.6% methylene blue removal in 40 min and 98.9% in 120 min, following the quasi-second-order kinetics, indicating chemisorption (electrostatic attraction) as the main mechanism. This work provides a mild, green approach to prepare PSA-COFs core–shell fibers, effectively solving the formability and processing issues of COFs.