Biosynthesis and characterization of gold nanoparticles and its application in eliminating nickel from water

This work synthesized gold nanoparticles (AuNPs) using a green method due to their rapid, low cost, non-toxic, and eco-friendly approach. The samples were prepared using the extract of lemon juice as a reducing and capping agent. The particle sizes and shapes were changed according to the reaction conditions. The AuNPs had been characterized using UV–visible spectroscopy (UV–Vis), high-resolution transmission electron microscope (HR-TEM), and Fourier transforms infrared spectroscopy (FTIR). The surface plasmonic resonance band were appeared at (564, 556, and 548 nm) at different concentrations of lemon extract in UV–Vis spectra. HR-TEM images showed that the AuNPs were formed with different shapes (spherical, trigonal, hexagonal, trapezoidal, pentagonal, rectangular, small rod, and oval). The average particle size of the spherical shapes was (54, 22, and 28 nm). FTIR results indicate the electrostatic interaction between AuNPs and oxygen atoms in CO due to the lone pair of electrons in oxygen atoms. The outcomes of the current study could assist in the environmental application as a minimizer of heavy metals such as nickel in water; nickel concentration was measured before and after using nanoparticles, and the concentration of nickel was decreased after passed through the filter with gold nanoparticles.