Reusable biogenic fabrication and structural analysis of Phyllanthus acidus-derived ZnO nanoparticles: Photocatalytic degradation of methylene blue dye and its biological applications

The Phyllanthus acidus leaf extract was used as a bioreducing/capping agent for the green and cost-effective synthesis of zinc oxide nanoparticles (ZnONPs). The nanoparticles are formed via phytochemical reduction of zinc ions. Characterisation of the ZnONPs using UV-Vis (λmax ≈ 344 nm), FTIR, FE-SEM, EDX, XRD, DLS, zeta potential and DSC analysis confirmed their crystalline nature, polydisperse size distribution and high thermal stability (endothermic peak at 255 °C). The nanoparticles, under natural sunlight, showed effective photocatalytic activity, with 99.8% degradation of Methylene Blue in 70 min following pseudo-first-order kinetics. The ZnONPs demonstrated excellent catalytic stability and reusability. These results demonstrate the potential for using P. acidus-derived ZnONPs for eco-friendly water purification and remediation, contributing to SDG 6 and SDG 12.