Efficient adsorption of Au(CN)2− from gold cyanidation with graphene oxide-polyethylenimine hydrogel as adsorbent

Abstract

The adsorption of gold cyanide complex ion (Au(CN)2−) on graphene oxide-polyethylenimine hydrogel (GO/PEI hydrogel) from gold cyanidation has been studied to explore the possibility of the application of GO/PEI hydrogel in gold cyanidation process for extracting gold from ores. The adsorption was carried out in artificial Au(CN)2− aqueous solution with GO/PEI hydrogel as adsorbent. The experimental results, as well as IR, XPS and SEM−EDS, have shown that GO/PEI hydrogel exhibited a high adsorption capacity and a fast adsorption rate of Au(CN)2−, suggesting that GO/PEI hydrogel might be a good adsorbent for the recovery of Au(CN)2−. The adsorption of Au(CN)2− on GO/PEI hydrogel obeyed the Langmuir isotherm model and fitted well with the pseudo second order model. The good recovery of Au(CN)2− was largely related to the porous structure, large specific surface area, as well as the oxygenous functional groups on the surface of GO/PEI hydrogel. Keywords: Graphene oxide, Polyethylenimine, Hydrogel, Cyanide complex ion