Enhanced Cd(II) ion Chemosensing by a Curcumin Extract -Silver nanoparticle Nanocomposite: Synthesis, Optimization and Characterization

Abstract The detection of Cadmium (Cd 2+ ), a toxic heavy metal of global concern commonly absorbed and accumulated by plants and animals in water are expensive with high technology. This study focused on preparing chemosensor for Cd 2+ that will be user and eco-friendly using readily available raw materials. The synthesis of chemosensor for Cd 2+ in water using silver nanoparticles functionalized curcumin (AgNps) solution was developed. The developed chemosensor (Ag 0 Cur) was monitored and characterized using Ultraviolet-Visible spectroscopy (Uv-Vis), Fourier Transform Infra-Red spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray spectroscopy (EDX). The chemosensor interacted spontaneously when in contact with the Cd 2+ ion in water, the Cd 2+ solution transformed to orange while those of Pb 2+ and Hg 2+ to yellow. The FTIR results revealed the interaction of the AgNps solution with curcumin in acetonitrile. Change was observed in the intensities of the absorption peaks of the nanocomposite compared with the peaks observed in curcumin. The Uv-Vis analysis further confirmed the interaction between the nanoparticle solution and the curcumin extract. The absorption observed around 239 nm and 420 nm in the curcumin extract shifted to lower wavelength of absorption around 235 nm and 357 nm when AgNps interacted with curcumin solution. The chemosensor SEM micrograph showed nano-fibre shapes which was found to be sensitive and selective on Cd 2+ in water to a detection limit of 0.0013 ppm compared with Hg 2+ and Pb 2+ , however, its sensitivity and selectivity was pH dependent in basic media. The chemosensor also tested positive on industrial effluent from foundries.