Innovative electrospun zein/polycaprolactone nanofibers loaded with graphene oxide: A superior adsorbent for effective lead ion removal from drinking water

This study explores the use of electrospun nanofibers (NFs) composed of zein and polycaprolactone (PCL) incorporated with graphene oxide (GO) nanoparticles for the removal and adsorption of heavy metals, specifically lead (Pb²⁺), from water. The NFs were characterized using spectroscopic techniques including X-ray diffraction, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA), which provided information about molecular interactions, morphology, crystallinity, thermal stability, and hydrophobicity. The average fiber diameter was approximately 776 nm, and the surface contact angle was measured at 90°, indicating hydrophobic properties. The NFs displayed semi-crystalline behavior and exhibited significant thermal degradation above 350 °C. Under optimal conditions—temperature of 30 °C, pH of 6, contact time of 30 to 90 min, and lead concentration between 1 and 25 mg/L—the Zein/PCL/GO NFs achieved over 85 % removal efficiency of Pb²⁺. The adsorption behavior aligned well with the Langmuir isotherm, and the kinetics were accurately described by a pseudo-second-order model. These results demonstrate that the NFs serve as high-capacity, efficient, and cost-effective adsorbents for heavy metal removal in water treatment applications.