Green Synthesis of Silver Nanoparticles Using Water Hyacinth Leaf Extract for Colorimetric Detection of Heavy Metal Ions

The green synthesis of silver nanoparticles have attracted many researchers due to their wide range of applications. The objective of this study is to synthesize silver nanoparticles using water hyacinth extract for the detection of metal ions in aquatic solutions. In the present study, the silver nanoparticles synthesis employing the leaf extract of water hyacinth as the capping and reducing agent has been reported. The particles showed absorption maxima at 406 nm establishing the formation of silver nanoparticles. The particles were characterized by FTIR, XRD, SEM-EDX, TEM and Zeta Potential. The polyphenols present in the leaf extract are accountable for reducing and the capping activity which was revealed in the FTIR spectra. XRD revealed the crystalline nature of the nanoparticles. The morphology, size and shape of the silver nanoparticles were investigated with the help of electron microscopy techniques. The silver nanoparticles are observed to be spherically shaped with an average diameter of 10.78 ± 4.61 nm. EDX spectra established the presence of elemental silver in the nanoparticles. A zeta potential of -31.7 mV was recorded indicating that the silver nanoparticles are stable. These biosynthesized silver nanoparticles were employed to detect metal ions in aqueous solutions and two metal ions (Hg<sup>2+</sup> and Fe<sup>3+</sup>) at 1000 micro molar concentration were detected successfully. Thus, the results of the study indicate that the silver nanoparticles synthesized from water hyacinth leaf extract have potential application in the detection of metal ions.