Green Synthesis of Fe3O4 Nanoparticles Using Green Betel Leaf Extract for Methylene Blue Adsorption

Abstract The synthesis of Fe3O4 nanoparticles has become a matter of interest because it has properties and useful applications in various fields. Using plant extracts using the green synthesis method to manufacture Fe3O4 nanoparticles is considered an effective, efficient, and environmentally friendly approach because it does not contain harmful chemicals. This study uses the green synthesis method to synthesize Fe3O4 nanoparticles from green betel leaf extract. The UV-Vis Fe3O4 nanoparticles showed continuous absorption at wavelengths between 300 nm and 800 nm and obtained a band gap energy of 1.87 eV. XRD analysis confirmed the crystal size of Fe3O4 nanoparticles (≈ 6.93 nm). The FTIR results show that functional groups from the leaf extract play a role in forming Fe3O4 nanoparticles, as evidenced by the presence of two Fe-O absorption bands at wave numbers 567 cm-1 and 482 cm-1. The SEM results showed a needle-like particle shape, the HR-TEM analysis showed spherical and needle-like shapes and nanoparticles size (≈ 29.82 nm) and the EDS analysis showed that Fe and O elements indicated the dominant iron oxide content of Fe3O4 with levels of 73.35% and 20.88%, respectively. The magnetization curve shows that the green synthesized magnetite has ferromagnetic properties. The ferromagnetic properties of Fe3O4 were then applied as methylene blue adsorbent and observed using UV-Vis spectroscopy, the most effective absorption ability was at a contact time of 120 minutes with a color degradation percentage of 98.75%. Keywords: Green synthesis, Fe3O4, Green betel, Adsorption, Methylene blue