Green synthesis of iron nanoparticles using Moringa oleifera extracts and their applications: Removal of nitrate from water and antibacterial activity against Escherichia coli

The importance of fabricating nanoparticles using plant extracts is being emphasized globally, as an alternative to traditional method because they are cost-effective, nontoxic, biocompatible and eco-friendly. In this study, green synthesis of iron nanoparticles (FeNPs) using leaf and seed extracts of Moringa oleifera (M. oleifera) were prepared by mixing different ratios of plant extracts with iron chloride solution. They were characterized using techniques such as dynamic light scattering, UV-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The UV-Vis spectrum of M. oleifera leaf (MOL) and seed (MOS) based on FeNPs showed absorption at 210 and 240 nm, respectively. In addition, the green application of synthesized nanoparticles for the removal of nitrate ion (NO3−) from surface and ground water was also investigated. The batch adsorption results showed an enhanced removal of NO3− by 85 % and 26 % MOS-FeNPs and MOL-FeNPs respectively as compared to M. oleifera extracts. Furthermore, the antibacterial activity illustrated that the maximum zone of inhibition against Escherichia coli was observed by MOS-FeNPs (6 mm), followed by MOL-FeNPs (5 mm). FeNPs were successfully fabricated using M. oleifera extracts, giving an alternative method to nitrate removal from surface and ground water.