Visual and colorimetric determination of mercury (II) based on lignosulfonate-capped silver nanoparticles

ABSTRACT Lignosulfonate /silver nanoparticles (L–AgNPs) were synthesized by a one-pot method. The structure of the prepared L–AgNPs was characterized by ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The prepared L–AgNPs were spherical with a size of approximately 16–22 nm, whereas the structure of lignosulfonate did not change during the synthesis. The synthetic method is green, simple and fast. As a heavy metal, establishing a green and rapid detection method for mercury ion is very important. L–AgNPs exhibited high selectivity for mercury (II), a detection range of 0–68 µM, and a minimum detection limit of 7 nM. The detection method developed in this work was used for the determination of mercury (II) in actual water samples, and the results agreed well with those obtained by a colorimetric method. This study provides a new idea for the practice of green chemistry and a novel method for the detection of mercury (II). GRAPHICAL ABSTRACT