A Coordination-Induced In Situ Self‐Assembly Strategy for High Structurally Stable Carboxymethyl Chitosan@HKUST-1/Polyvinylidene Fluoride Electrospun Fibers

Metal-organic frameworks (MOFs) have shown great promise for water treatment owing to their tunable porous structures and abundant active sites. However, the practical application of conventional MOFs, such as HKUST-1, is still limited by insufficient structural stability in aqueous environments and poor recoverability in powder form. Herein, a coordination-induced in situ self-assembly strategy was developed to fabricate structurally stable carboxymethyl chitosan (CMCS)@HKUST-1/polyvinylidene fluoride (PVDF) electrospun fibers. In detail, Cu 2+ was first incorporated into PVDF matrix by electrospinning to obtain Cu 2+ /PVDF fibers, which were subsequently immersed in a mixed ligand solution containing 1,3,5-benzenetricarboxylic acid (H 3 BTC) and CMCS, enabling the in situ growth of CMCS-modified HKUST-1 on the fiber matrix. CMCS participated in the coordination-induced assembly process mainly through -COOH/-COO⁻, thereby strengthening the Cu-O coordination environment and improving the resistance of HKUST-1 to water-induced structural degradation. Meanwhile, the flexible CMCS chains and their hydrophilic functional groups enhanced the interfacial interaction, wettability, and accessibility of adsorption sites within the composite fibrous network. The practical potential of CMCS@HKUST-1/PVDF electrospun fibers was evaluated through the treatment of simulated dyeing wastewater, in which it exhibited a high Congo red adsorption capacity of 173.08 mg/g and maintained robust structural stability under elevated temperature treatment at 70 ℃, as well as in aqueous environments over a pH range of 6–10. This work provides a facile and effective strategy for constructing recoverable, structurally stable, and high-performance MOF-based fibrous adsorbents for water treatment applications.