Biofabrication of Silver Nanoparticles for Selective and Sensitive Colorimetric Detection of Hg(II) Ions

Abstract

The current study explored a green, simple, selective and cost-effective method for the detection of Hg2+ ions in the aqueous medium using silver nanoparticles (AgNPs) synthesized from marine macroalgae Sargassum duplicatum. The biosynthesized AgNPs were further characterized by using UV-visible spectroscopy, FTIR, HR-TEM, SAED and XRD techniques. The synthesized AgNPs were almost spherical in shape and polydisperse in nature. Due to the intense SPR absorption band, the biosynthesized AgNPs solution is seen as dark brown colour. In the presence of Hg2+, the brown coloured AgNPs solution becomes colourless coupled with the disappearance of absorption maxima at 419 nm. The selectivity and sensitivity of AgNPs towards Hg2+ were also investigated and the minimum detection limit was found to be 0.1 μM. Furthermore, a test strip technique for the rapid detection of Hg2+ was also devised. Thus, the biogenic AgNPs are expected to be a promising candidate for developing low-cost Hg2+ sensors.