Biofabrication of Fe nanoparticles in aqueous extract of Hibiscus sabdariffa with enhanced photocatalytic activities

Hibiscus sabdariffa is a strongly basic dye with a large number of medicinal applications and is used for various diagnostic purposes. The biofabrication of Fe nanoparticles using Hibiscus sabdariffa (Roselle) flower extract is an eco-friendly and cost-effective protocol reported for the first time in the present investigation. The natural plant extract acts as a non-toxic, biodegradable and economical reducing agent in the biosynthesis of the Fe nanoparticles. Different well-known complementary characterization techniques such as UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), dynamic light scattering (DLS) and thermogravimetric analysis-differential scanning calorimetry (TGA-DSC) were used to investigate the morphological, structural and optical properties of the as-synthesised Fe nanoparticles. The resulting nanoparticles were then utilized as a photocatalyst for the degradation of the toxic organic dye Congo red (CR). UV-visible spectroscopy was used to determine the photocatalytic performance of the Fe nanoparticles under UV irradiation. The results of the photocatalytic degradation of Congo red in aqueous solution under UV light showed a higher photocatalytic activity. A reasonable mechanism was proposed for the enhanced photocatalytic activity of the Fe nanoparticles.