Synergistic adsorption-degradation of methylene blue via electrospun ZIF-67/PAN nanofibers: performance and mechanisms

Though MOFs show potential for organic dye wastewater treatment, their practical use is limited by poor recoverability of powdered MOF-based adsorbents/catalysts. To address the recovery issues and agglomeration tendencies inherent in metal-organic framework (MOF) powders, this study presents the synthesis of ZIF-67/PAN composite nanofibers via an electrospinning technique, effectively immobilizing ZIF-67 nanoparticles onto a polyacrylonitrile (PAN) matrix. The resulting composite exhibited a high specific surface area of 663.06 m 2 /g and demonstrated exceptional dual functionality for methylene blue (MB) removal. It achieved a high adsorption capacity of 1169.23 mg/g at 45 °C and enabled ultrafast catalytic degradation, achieving 100 % MB removal within 10 min through peroxymonosulfate (PMS) activation. Density functional theory (DFT) calculations revealed that demethylation and ring-opening served as the dominant degradation pathways, facilitated by the generation of sulfate (SO 4 · - ) and hydroxyl (·OH) radicals via Co 2+ /Co 3+ redox cycling. The composite material demonstrated outstanding pH resilience across a broad range (pH 3–9) and significantly reduced the ecotoxicity of degradation intermediates. Furthermore, the ZIF-67/PAN fibers exhibited excellent reusability, maintaining high performance over five consecutive cycles with an efficiency loss of less than 8 %. This work provides a robust, scalable, and environmentally friendly strategy for industrial dyeing wastewater treatment.