Detection of mercury in aqueous system via O-Phenylenediamine using polyvinyl pyrrolidone functionalized silver nanoparticles

This study reports colorimetric detection of mercury (Hg2+) by using polyvinyl pyrrolidone-capped silver nanoparticles (PVP-AgNPs) and O-phenylenediamine (OPD) in aqueous samples. Yellow-colored PVP-AgNPs aggregate in the presence of OPD and simultaneously oxidize it to 2,3-phenazinediamine forming a green-colored solution. In the presence of Hg2+, aggregated PVP-AgNPs form silver amalgam and 2,3-phenazinediamine quenches in the system. UV-visible, FT-IR (Fourier transform infrared) and fluorescence spectroscopy, fieldemission scanning electron microscopy (FESEM), particle size analysis and zeta potential analysis were used to characterize the PVP-AgNPs. The maximum absorption of PVP-AgNPs occurred at 397 nm, while the hydrodynamic size measured using a particle size analyzer was determined to be 22.66 nm. PVP-AgNPs exhibited a surface charge of -20.2 mV. The study established a limit of detection for Hg2+ of 3.29 mu M with a linear range of 10-80 mu M. Various environmental factors including pH, salinity and temperature were examined regarding their impact on Hg2+ detection. The research proposes that the developed method, characterized by high selectivity and sensitivity, could serve as an effective colorimetric approach for quantifying Hg2+ in diverse aqueous solutions.