Unmodified Green Silver Nanoparticles as Multisensor for Zn2+ and Catalyst for Environmental Remediation

This paper details the selective optical, fluorescent and electrochemical detection of Zn2+ among various divalent metal ions in aqueous solution by the green synthesized silver nanoparticles (AgNP) using the fresh extract of Myristica fragrans (MF) with the aid of microwave energy. The synthesized silver nanoparticles stabilized with MF were analysed using UV-vis., Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. Due to the effective complexation between silver nanoparticles and metal ions, absorbance of AgNP-MF diminished with increasing concentration of Zn2+. This is visually identified through the color changes. Fluorescent sensing studies involved the changes in fluorescent intensity of AgNP-MF in the presence of Zn2+. Electrochemical sensing of Zn2+ was carried through cyclic and differential pulse voltammetric techniques using AgNP-MF modified platinum electrode (AgNP-MF-Pt). The developed electrochemical sensor showed a limit of detection (LOD) of 0.6148 mu M and its good sensing ability was checked for the detection of Zn2+ in environmental water samples. Recoveries of Zn2+ in the various real water samples were obtained in the range from 100.2 % to 100.6 %. The multi-functional utility of the AgNP-MF as a catalyst towards the reduction of two environmentally toxic contaminants such as o/p-nitroanilines through NaBH4 was also evaluated. The complete degradations were achieved within few minutes and the reactions followed pseudo first order kinetics. The effect of catalytic dosage on the rate of reduction reactions was also studied.

Automated summary

This study demonstrates the selective optical, fluorescent, and electrochemical detection of Zn2+ using silver nanoparticles synthesized with fresh extract of Myristica fragrans. The synthesized nanoparticles showed effective complexation with Zn2+, leading to decreased absorbance and fluorescent intensity. The electrochemical sensor based on these nanoparticles exhibited a low limit of detection for Zn2+ and good sensing ability in environmental water samples. Additionally, the nanoparticles showed catalytic activity towards the reduction of environmental contaminants with rapid degradation achieved within minutes.