THE MECHANISM OF ADSORPTION OF AU(CN)4- ONTO ACTIVATED CARBON

The Au(CN)4- species adsorbs onto activated carbon as a chemically unchanged ion pair of the type Mn+[Au(CN)4-]n, in a manner similar to that postulated for Au(CN)2-. The affinity of carbon for Au(CN)4- is greater than that for Au(CN)2-. A Mossbauer spectroscopic investigation has confirmed that Au (CN)4- is the species adsorbed from both acidic and neutral solutions. The Mossbauer spectrum of carbon that is loaded with Au(CN)4- and subsequently boiled in hydrochloric acid is interpreted in terms of the presence of Au(CN)2Cl2-, Au(CN)2- and AuCN as products of the decomposition of Au(CN)4-.