A Novel Study on Antioxidant Activity and Catalytic Reduction of Methylene Blue using ZnO Nanoparticles Synthesized via the Middle Part of Walnut Shell (Juglans regia) Extract

The synthesized ZnO nanoparticles were characterized using UV-Vis spectroscopy, SEM, XRD, FTIR, and TEM analysis. The catalytic activity of the prepared green catalyst ZnO nanoparticles was also investigated in the dye methylene blue (MB) decomposition. The catalytic decomposition reaction completed within 20 minutes, demonstrating the excellent catalytic properties of ZnO nanoparticles in reducing MB. This research describes the green synthesis of ZnO nanoparticles using an extract of the middle part of a walnut shell (Juglans regia). The antioxidant activities (radical capture capacity) of the synthesized ZnO nanoparticles were evaluated by the 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) assay at different ZnO nanoparticle concentrations, and the radical capture activity was achieved at IC50 = 146.32 μg / mL. The radical capture activity was achieved at IC50 = 146.32 μg / mL. The biosynthesis of ZnO nanoparticles was caused by hydroxide precipitation at room temperature after calcination at 450°C.