Study On The Adsorption And Characterization Of Silver On Activated Carbon

Activated carbon supporting silver has been widely used in water treatment and catalyst. The adsorption and distributing of silver on activated carbon were studied. The study results indicated: (1) Adsorption of silver on activated carbon was not influenced by the ion intensity in solution but ligand or surface oxidation modification of activated carbon with nitric acid and hydrogen peroxide. Ammonia had different influence on adsorption of silver from sodium thiosulfate. Surface oxidation modification of activated carbon made against adsorption of Ag+ and [Ag(S2O3)2]3-, but made for that of [Ag(NH3)2]+. Organic compound adsorbed on activated carbon significantly increased the reduction capacities of activated carbon for silver ion. After activated carbon was soaked in reducing agent (20% N2H4H2O) for three hours, the reduction capacity of activated carbon for silver ion did not change. (2) Silver on activated carbon mainly distributed outside. The difference of concentration of silver ion and the adsorption time resulted in different distributing of silver. When silver ion formed coordination compound or after activated carbon was modified with nitric acid and hydrogen peroxide, the distributing of silver on activated carbon changed. (3) X-ray diffraction pattern of activated carbon supporting silver showed that silver ion was deoxidized to elemental crystal on activated carbon. The adsorption and distributing of silver also testified indirectly the reduction of silver ion on activated carbon.