Adsorption of sulfur dioxide by active carbon treated by nitric acid:: I.: Effect of the treatment on adsorption of SO2 and extractability of the acid formed

The process of adsorptive-catalytic cleaning of gas from sulfur dioxide using active carbon, treated by concentrated nitric acid, was studied. After oxidative treatment the acidity of the carbon increases and the basicity decreases. This results in an increase of the SO2 adsorption and its oxidation to SO3, and in weaker retention of the sulfuric acid formed. This facilitates the removal of H2SO4 by washing of the carbon and allows to obtain a more concentrated acid. The efficiency of the treated carbon is also higher in the process of SO2 removal from a gas similar in composition to stack gases. (C) 1997 Elsevier Science Ltd.