Investigation of bacteriostatic performance of the one-pot bio-fabricated ZnONPs using Saraggrssum extract for photocatalytic degradation of malachite green dye

This study presents the eco-friendly synthesis of zinc oxide nanoparticles (ZnONPs) using Sargassum wightii extract as stabilizing agent. Characterization techniques, including UV–vis, XRD, TEM, and EDX, were applied and confirmed the formation of ZnONPs. Upon first characterization using UV–vis spectroscopy, a noticeable absorption peak was seen at 364 nm, corresponding to the ZnO absorption band gap. The crystalline nature of the ZnONPs was confirmed by further structural study using XRD, which showed peaks matching ZnO crystalline phases. TEM revealed the mostly spherical shape of the ZnONPs, with a small size. The photocatalytic degradation experiment of malachite green (MG), the results exhibited a complete degradation (100%) of MG dye after exposure to 100 mg/L of ZnONPs at 90 min under visible light. The recyclability performance of ZnONPs reached 94.2% after 5 cycles. Additionally, antibacterial potential was evaluated of ZnONPs against Salmonella enterica, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis. Significantly, more extensive zones of inhibition corresponded with increasing doses of ZnONPs. After 200 min of treatment, time-dependent bactericidal effects were also recorded. In conclusion, this study emphasizes the potential of ZnONPs as effective antibacterial agents and highly efficient photocatalysts for degrading dyes. Their rapid synthesis utilizing SW extract as a green approach is shown, highlighting its potential applying to address environmental concerns, including water pollution.