Behaviour of activated carbons obtained from mixtures of oil-fired fly ash and oil refining pitch Original Research Article

Chars were obtained by the pyrolysis of mixtures of oil refining pitch and carbon-fired fly ash. These materials, after activation with CO2 at 900 °C, produced activated carbons with high surface area, high content of oxygen, and surface sites with prevalent basic characteristics. The amount of SO2 adsorbed by the carbons produced increases with an increase in the amount of added ash. Subsequent leaching with water allows the distinction of three forms of SO2: (a) a portion that desorbs as SO2; (b) a portion that desorbs as SO3; and (c) a portion that cannot be recovered by leaching with water. The addition of ash favours the process by which SO2 can be desorbable as SO3 or cannot be desorbable. This behaviour is enhanced by the presence of NOx in the gaseous adsorption mixture.