Gold@Silver bimetallic nanoparticles: fabrication and removal of toxic chromium(VI)

Abstract

Gold@Silver bimetallic nanoparticles (Au@Ag NPs) were fabricated by using galvanic displacement reaction with soft template cetyltrimethylammonium bromide (CTAB). UV–visible spectroscopy, TEM, EDX, and XRD used to determine the morphology of Au@Ag NPs. The surface plasmon resonance (SPR) band position strongly depends on the ratio of metal salt precursors. Au@Ag employed as an adsorbent to the chromium(VI) removal from an aqueous solution. Effects of adsorption time, pH, temperature, the dose of Au@Ag, and concentration of chromium(VI) were studied and the removal percentage was calculated. Langmuir adsorption monolayer, Freundlich, intraparticle diffusion, and multilayer adsorption isotherms were used for the determination of maximum adsorption efficiency and adsorption isotherm parameters. The kinetics of chromium(VI) removal have also been discussed with various kinetic rate laws. Chromium (VI) adsorption followed Langmuir isotherm and the pseudo-second-order model with the highest linear regression coefficient.