Green Synthesis of Fe3O4/Chitosan Nanoparticles Utilizing Moringa Oleifera Extracts and Their Surface Plasmon Resonance Properties

Abstract

In this study, a simple, rapid, and environmentally friendly green approach for synthesizing Fe3O4 and Fe3O4/chitosan nanoparticles with various concentrations was developed. The nanoparticles had a spherical shape with a cubic inverse spinel structure. The functionalization of the Fe3O4 nanoparticles using chitosan increased the crystallite size of the nanoparticles from 7.2 to 7.8 nm. The Fourier transform infrared spectra of the Fe3O4/chitosan nanoparticles showed the existence of the characteristic peaks of chitosan in addition to a peak at 578 cm−1, which corresponds to the stretching of the Fe−O group. The UV-visible spectra demonstrated a wide absorption band with the appearance of small peaks of chitosan absorption at 205 and 215 nm. The saturation magnetization of the Fe3O4 was 54.1 emu g−1. The surface plasmon resonance (SPR) measurements showed an enhancement in the SPR angle as the ratio of chitosan to Fe3O4 increased, wherein the angle shift from 0.17° to 1.91°. The chitosan covering the Fe3O4 nanoparticle surface caused the refractive index to change, which increased the SPR angle shift. The obtained results indicated that the SPR properties of the Fe3O4 nanoparticles were significantly improved by modification with chitosan. These results also indicated that the use of chitosan in Fe3O4 nanoparticles can enhance SPR properties, which has potential for future SPR-based sensor applications.