Fabrication of Polyacrylonitrile/Montmorillonite/MIL-101(Fe)-NH ₂ Nanofibers via Electrospinning for Methylene Blue Removal

Methylene blue (MB), a widely used organic dye in wastewater, poses substantial environmental and health hazards. To address this issue, the novel PAN/MMT/MIL-101(Fe)-NH₂ (PMMN) composite nanofibers were developed via electrospinning. These materials incorporate an amino-functionalized metal-organic framework (MOF) and montmorillonite (MMT) into a polyacrylonitrile (PAN) matrix, effectively preventing MOF particle agglomeration, enhancing active site accessibility, and enabling facile reusability to avoid secondary pollution. Characterization by XRD, FT-IR, SEM, TEM, and EDS confirmed the synthesis of the composite, while water contact angle measurements demonstrated its hydrophilic properties. Batch adsorption experiments revealed a high MB adsorption capacity of 433.98 mg·g⁻¹, with equilibrium achieved within 180 min. Dynamic adsorption tests showed breakthrough and saturation volumes of 225 and 1300 mL, respectively. The adsorption process was well described by the pseudo-second-order kinetic model and Langmuir isotherm, indicating monolayer chemisorption as the dominant mechanism. XPS analysis further elucidated that the adsorption mechanism involves multiple synergistic effects, including electrostatic interactions, hydrogen bonding, coordination, and π-π stacking. The findings indicate that the PMMN composite nanofibers exhibit considerable potential as an efficient adsorbent for the removal of MB from aqueous solutions.