A Comparative Study of PEGylated and PVPylated Surface-functionalized Zinc Oxide Nanoparticles for Environmental Applications

Zinc oxide (ZnO) nanoparticles possess notable antibacterial and photocatalytic properties, yet the lack of comparative studies on PEGylated and PVPylated functionalized ZnO limits understanding of how surface modifications influence their effectiveness. A comparative study was conducted on ZnO nanoparticles synthesized using polyethylene glycol (PEG-ZnO) and polyvinylpyrrolidone (PVP-ZnO) as stabilizing agents, with zinc nitrate as the precursor. The synthesized nanoparticles were characterized using UV–Visible spectroscopy, X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and particle size analysis. Antibacterial activity was evaluated against Escherichia coli (MTCC: 912), Bacillus subtilis (MTCC: 121), and Streptococcus pyogenes (MTCC: 1925) using the well diffusion method. Photocatalytic efficiency was assessed through the degradation of methyl orange under sunlight irradiation using 100 mg of catalyst. UV–Vis analysis confirmed the formation of ZnO nanoparticles with absorption peaks at 203 nm (PEG-ZnO) and 207 nm (PVP-ZnO). X-ray diffraction patterns revealed crystalline nature, while EDX analysis confirmed the elemental composition of ZnO. Scanning electron microscopy images showed spherical morphology with minimal aggregation. Particle size analysis indicated average size of 330 ± 80 nm (PEG-ZnO) and 679 ± 45 nm (PVP-ZnO). PEG-ZnO exhibited enhanced antibacterial activity, with inhibition zones of 16.66 ± 0.66 mm (E. coli), 16.00 ± 0.88 mm (B. subtilis), and 13.66 ± 2.08 mm (S. pyogenes) at 100 mg/mL concentration, significantly higher than PVP-ZnO and control (p < 0.001). In the degradation study, PEG-ZnO achieved 95.16% methyl orange degradation within 50 minutes, significantly outperforming PVP-ZnO, which showed 84.16% degradation over the same period. These findings suggest that PEG- and PVP-functionalized ZnO nanoparticles are promising candidates for biomedical applications and environmental remediation.