Green Synthesis of Manganese Nanoparticles Using Grevillea robusta (Silky Oak) Bark Extract: Their Characterization and Sustainable Approach for Anticorrosive Application

Introduction: The present study investigates the green synthesis of manganese nanoparticles (MnNPs) using Grevillea robusta (Silky Oak) bark extract. The objective of this study is to develop an eco-friendly, sustainable, and cost-effective method for nanoparticle production, with potential application as corrosion inhibitors in industrial metal protection. Methods: MnNPs were synthesized by carefully optimizing several parameters such as precursor concentration, extract-to-precursor ratio, pH level, reaction time, and temperature to maximize nanoparticle yield. The formation of MnNPs was confirmed using UV–Vis spectroscopy, and the morphology was analyzed through Scanning Electron Microscopy (SEM). The elemental composition was assessed using Energy Dispersive X-ray Spectroscopy (EDS), and Dynamic Light Scattering (DLS) was employed to determine the hydrodynamic size of the nanoparticles. The anticorrosive performance of the MnNPs against mild steel corrosion was evaluated using Potentiodynamic Polarization (PDP) and weight loss analysis. Results: UV–Vis analysis showed a distinct absorption peak at 286 nm, confirming the synthesis of MnNPs. SEM images revealed predominantly spherical particles. EDS analysis indicated a composition of 65.49% manganese and 34.51% oxygen. The DLS results showed an average hydrodynamic diameter of approximately 440 nm. The formulation with 10 mg MnNPs and 10 mL bark extract demonstrated the highest corrosion inhibition efficiency, reaching 85.1% (PDP) and 87.4% (weight loss method). Discussion: The findings demonstrate that the green-synthesized MnNPs exhibit excellent anticorrosive properties, making them suitable for industrial applications. The eco-friendly synthesis process aligns with sustainable development goals and shows compatibility with similar plantbased nanoparticle synthesis methods reported in previous studies. However, limitations include the need for further research on the long-term stability, large-scale production, and real-world industrial performance of these nanoparticles. Conclusion: The study successfully presents a green synthesis approach for producing MnNPs using Grevillea robusta bark extract, with significant potential as an effective and environmentally safe corrosion inhibitor for industrial use. These findings contribute to the development of sustainable nanotechnology solutions in corrosion prevention.