Biosynthesis of silver nanoparticles from water hyacinth plant leaves extract for colourimetric sensing of heavy metals

In this day, silver nanoparticles (Ag-NPs) have gained tremendous popularity in the world in the field of sensors because of its outstanding and significance optical, electronic and chemical properties. Herein, we report for the first time the green and cost-effective synthesis of silver nanoparticles using hyacinth plant leaves for colourimetric sensing of heavy metal ions in solution. The optical and structural properties of the as-prepared Ag-NPs were determined using, absorption spectroscopy, Fourier transforms infrared spectroscopy (FTIR), dynamic light scattering (DLS), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The TEM micrograph shows the nanoparticles are uniformly distributed and spherical in shape with an average diameter of 10.46 nm. The XRD analysis show that the as-synthesized materials are nanocrystalline in nature with the face centred cubic (FCC) phase while the EDS spectrum revealed distinct signals in the silver region confirming the formation of Ag-NP. The colourimetric sensing study indicated that the as-synthesized Ag-NPs showed a good response to different heavy metal ions with good selectivity towards Hg²⁺.