Green synthesis of zinc oxide nanoparticles using fruit extract and zinc nitrate hexahydrate for photocatalytic, antioxidant, and antibacterial activities

Using zinc nitrate hexahydrate as the precursor and Rhus vulgaris fruit extract as a natural reducing and capping agent, this study describes the environmentally friendly synthesis of zinc oxide nanoparticles (RV-ZnONPs). The presence of bioactive substances like phenols, flavonoids, tannins, alkaloids, saponins, terpenoids, steroids and glycosides responsible for the reduction of Zn 2+ ions nucleation and stabilization of ZnONPs. UV-Vis spectroscopy, X-ray diffraction (XRD), zeta potential analysis (XRD), transmission electron microscopy (TEM) and Fourier-transform infrared (FT-IR) spectroscopy were used to characterize the biosynthesized RV-ZnONPs. A distinctive absorption peak with an estimated band gap energy of 3.20 eV was found by UV–Vis analysis at approximately 371 nm. While TEM images revealed primarily irregular nanoparticles with an average size of ∼23. 5 nm, XRD confirmed the formation of highly crystalline ZnONPs with a hexagonal wurtzite structure and an average crystallite size of ∼22.7 nm. Excellent colloidal stability was demonstrated by the high negative zeta potential value (−35.1 mV) and FT-IR analysis verified the role of functional groups derived from plants in capping and stabilizing nanoparticles. The photocatalytic, antioxidant, and antibacterial properties of RV-ZnONPs were also assessed. Under UV irradiation, the RV-ZnONPs demonstrated effective photocatalytic degradation with maximum degradation rate of 65.4%. The degradation efficiency rose with nanoparticle concentration and reaction time. Antioxidant activity assessed by the DPPH assay demonstrated concentration-dependent free-radical scavenging with RV-ZnONPs showing a significantly lower IC 50 value (74.46 µg/mL) compared to the extract from crude fruit. Furthermore RV-ZnONPs demonstrated significant antibacterial activity against Staphylococcus aureus and Escherichia coli which was ascribed to membrane disruption, reactive oxygen species generation, and Zn 2+ ion release. This study highlights the promising potential of Rhus vulgaris fruit extract for environmental remediation antioxidant applications and antimicrobial treatments by demonstrating that it offers an efficient green pathway for the synthesis of stable and multifunctional ZnONPs.