An experimental study on the adsorption behavior of gold glycinate complex on graphene oxide

Abstract

Graphene oxide (GO) has recently gained plenty of attention as an effective adsorbent for gold recovery from leaching solutions, primarily due to its larger surface area compared to activated carbon (AC). In this study, the adsorption behavior of gold glycinate complex (Augly2−) on GO surface was investigated using equilibrium isotherm and kinetic studies for the first time. The optimal conditions for adsorption were determined using an experimental design software (DX-13) based on the response surface method (RSM). These conditions were found to be a pH of 10.5, GO dosage of 0.6 g L−1, gold concentration of 6 mg L−1, and contact time of 10 h, resulting in the adsorption percentage of 74.2% and adsorption capacity of 7.4 mg g−1. The equilibrium isotherm studies indicated that the adsorption process adhered to the Freundlich isotherm model. Additionally, the results of the kinetic study revealed that the pseudo-second-order model exhibited a stronger correlation with the experimental data compared to other kinetic models. Surface analysis studies using Fourier transform infrared (FTIR) spectrometer, X-ray diffraction (XRD), and scanning electron microscope with energy dispersive X-ray (SEM-EDX) spectroscopy demonstrated that the remarkable recovery of Augly2− was mainly attributed to the presence of oxygen containing functional groups on the GO surface.