Abstract
The study reports on the development of innovative hierarchical hybrid nanofibers for the efficient removal of cationic heavy metals and dyes from wastewater. The successful electrospinning of poly-(vinyl alcohol) (PVA) and chitosan (CS) in combination with biosynthesized copper oxide nanoparticle-doped graphene oxide nanocomposites (CuO-GO NCs) at various ratios produced functional nanofibers. The CuO-GO NC was synthesized with a facile one-step method. The cross-linked nanofibers were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), electron microscopy (SEM and TEM), energy-dispersive X-ray (EDX), and thermogravimetric analysis (TGA). SEM results revealed that electrospun nanofibers displayed defect-free uniform spindle-like morphologies with CuO-GO partially embedded onto nanofibers, having average diameters ranging from 52.53 to 65.57 nm. Further, TEM images reveal that CuO-GO is homogeneously dispersed within the nanofiber structure. The thermal analysis demonstrated that the embedded CuO-GO in nanofibers improved the thermal properties and phase change behavior. The nanofibers with 1 wt % CuO-GO performed excellently with a maximum adsorption capacity of 155.23 mg/g for MB dye and 179.9 mg/g for Pb (II) ions. Moreover, the nanofibers exhibited superior removal efficiencies of 89.81% for Pb-(II) ions and 77.67% for MB dye. The optimal pH values for MB dye and Pb-(II) ion adsorption were determined to be 9.1 and 5.5, respectively. The recycling results demonstrated that the cross-linked nanofiber retained excellent stability and performance after four cycles. In this study, 1 wt % CuO-GO-loaded cross-linked PVA/CS nanofibers showed potential adsorption properties for treating MB and Pb (II) ions, making it suitable for wastewater treatment applications with high efficiency.