Detection of Cu 2+ ion by Synthesis of Bio- mass-Silver Nanoparticle Nanocomposite

Monitoring the levels of potentially toxic metal ion like Cu2+ in aquatic ecosystems is important because this ion can have severe effects on human health and the environment. In this work we concentrate on an optical assay of the Cu2+ ion using a nanocomposite of bio-mass (humic acid)-silver nanoparticle (HA-AgNP). A sensitive colorimetric method has been developed using this composite for detection of Cu2+ ion based on changes in absorbance resulting from metal ion-induced aggregation of silver nanoparticles. Thereby morphology of the nanoparticles changes from hexagonal or spherical to rod like structure. At the same time stable inner complex formation of the metal ion is evidenced from the appearance of a peak at around 720 nm in UV-Visible spectra. Various concentrations of Cu2+ ion were used to test the linearity and sensitivity limit of the nanocomposite. The complex formation between Cu2+ ion and humic acid present in HA-AgNP nanocomposite is further confirmed from the FTIR spectra. Values for Cu2+-complexes available in the literature are in conformity with our findings. XRD pattern confirms that Cu exists in the form of ions in the complex. The quenching properties of the fluorescence study of the nanocomposite have been utilized for detection of Cu2+ ion. Index Term: HA-AgNP nanocompositeHumic acidColorimetric sensorDetection of Cu2+ ionEstimation of Cu2+ ion • Cu-complexCalibration curve