A AU-197 MOSSBAUER STUDY OF THE ADSORPTION OF AUROCYANIDE ONTO ACTIVATED CARBON

The chemical state of gold adsorbed on activated carbon from solutions of KAu(CN)2 has been studied by197Au Mössbauer spectroscopy as a function of the pH and concentration of the solution, the loading of the carbon, and the drying conditions of the samples. On freshly prepared specimens Au(CN)2- is always the dominant species. Drying leads to the formation of other forms of gold, mainly in samples loaded from strongly acidic media. An oligomeric form of AuCN is, however, also formed when samples loaded at high pH values are dried at temperatures around 100°C. © 1990 J.C. Baltzer A.G. Scientific Publishing Company.