The adsorption of silver cyanide on activated charcoal

Abstract

Experiments have been carried out on the adsorption of silver cyanide on charcoal from solution having various concentrations of sodium, calcium, free cyanide, and hydrogen ion. It has been found that sodium and calcium ions enhance the adsorption of silver cyanide on charcoal while free cyanide ions reduce the adsorption. A qualitative description of the adsorption based on the structure of the electrical double layer has been proposed to explain the effect of sodium, calcium and free cyanide ions on the adsorption. Increasing acidity of solution enhances the adsorption of silver cyanide on charcoal except in a certain pH range. The adsorption of silver cyanide in acid solution seems to be influenced by the zeta potential of the charcoal particles rather than by the adsorption of hydrogen ions. The adsorbability of different size ions on charcoal has been determined. The larger ions have a greater adsorption potential as shown by the order of adsorption amount with gold cyanide > silver cyanide > cyanide.