AFFINITY OF ACTIVATED CARBON TOWARDS SOME GOLD(I) COMPLEXES

The adsorption of dicyanoaurate(I), dithioureaaurum(I), dithiocyanatoaurate(I), and dithiosulfatoaurate(I) complexes onto activated carbon has been investigated. A flow-through miniature column connected on-line to a flow injection analysis system with a flame atomic absorption spectrometry detector provided information on the relative rates and extent of adsorption of gold(I) complexes. The corresponding adsorption isotherms have also been determined. Scanning electron micrographs of the barren and loaded carbon surfaces (from K[Au(SCN)2]) are presented. These show that Au(SCN)2-1 is reduced to metallic gold on the carbon surface. It is established that the effectiveness of activated carbon in removing complexed gold from aqueous solutions decreases in the following ligand order: SCN- > SC(NH2)2 > CN- ≫ S2O32-. © 1990.