Synthesis of Carbon Stabilized Zinc Oxide Nanoparticles and Evaluation of Its Photocatalytic, Antibacterial and Anti-biofilm Activities

The present study reports a microwave assisted chemical co-precipitation method to synthesize carbon stabilized zinc oxide nanoparticles (ZnO NPs). The NPs were characterized by using UV–visible spectrophotometer, scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). UV–visible absorption spectra showed an absorption maximum at 385 nm. Hydrodynamic size distributions of ZnO NPs were measured by using particle size analyzer. ZnO-C-0.5 showed the lowest size, 55 nm compared to other particles. All the carbon coated particles showed a zeta potential of > − 30 mV indicates the stability of the particles. The rate of ·OH formation was higher in case of ZnO-C-0.5 compared to ZnO-C-0.25, ZnO-C-0.75 and ZnO-C-1. ZnO-C-0.5 showed excellent dye degradation efficiency under visible light and followed by ZnO-C-0.75, ZnO-C-0.25 and ZnO-C-1 with a degradation efficiency of 63.45, 58.49, 47.97 and 47.31% respectively. In addition to this ZnO-C-0.5 exhibited enhanced photostability and reusability. The antibacterial and antibiofilm activity of ZnO-C NPs were studied by using Staphylococcus aureus and Pseudomonas aeruginosa bacterial species. At 10 µg/L, ZnO-C-0.5 showed 100% inhibition of both the bacterial species. The increase or decrease in carbon ratio decreased the photocatalytic efficiency and antibacterial and antibiofilm effect. The presence of carbon enhanced the antibacterial and antibiofilm effects and ZnO-C-0.50 exhibited highest activity.