Adsorption and reaction behavior for the simultaneous adsorption of NO–NO2 and SO2 on activated carbon impregnated with KOH Original Research Article

This study examined the individual and simultaneous adsorption of NOx (NO–NO2) and SO2 on activated carbon impregnated with KOH (KOH-IAC). For individual component adsorption, KOH-IAC showed a higher adsorption capacity in NO–NO2 rich air than in SO2–air. In the simultaneous adsorption of NO–NO2–SO2, SO2 showed a greater adsorption affinity than NO–NO2. The smaller the amount of NO–NO2 adsorbed, the more SO2 was adsorbed. XPS analysis of the adsorption of NO–NO2 rich SO2–air on KOH-IAC revealed that the adsorbed SO2 was predominantly found on the external surface, producing mainly K2SO4 and, additionally, H2SO4 and K2SO3. Depth profile analysis showed that the amount of SO2 adsorbed decreased regularly away from the surface, while the amount of adsorbed NO–NO2 increased irregularly. We confirmed that the presence of the impregnant in KOH-IAC is a determining factor in the adsorption of NO–NO2 and SO2 by chemical reaction, clarifying the surface chemical behavior.