Performance of fixed-bed KOH impregnated activated carbon adsorber for NO and NO2 removal in the presence of oxygen

KOH-impregnated activated carbon (K-IAC) was used in this study. This paper contains observation the adsorption behavior of NO and NO₂ with/without oxygen and with different bed depths of adsorbent. The paper also defines surface chemical changes due to NO_x adsorption. By using a simple design of adsorber, the packed amount of adsorbent for NO_x abatement for 6 months on a pilot scale was calculated. When oxygen was present, NO and NO₂ had a great improvement in adsorptivity. Adsorption of NO₂ forms a oxide crystal on the surface of the K-IAC and at the same time produces NO, which acts to bring about increased adsorptivity. The higher the bed of adsorbent was, the more NO was produced and the longer the breakthrough time took. The adsorber was designed in a scale-up condition where NO, NO₂ and O₂ were applied to K-IAC. The adsorbate that consumed the least packed amount was NO₂-air followed by NO₂-N₂, NO-air and NO-N₂. The results of the experiment demonstrated that with regard to adsorption of NO and NO₂ on K-IAC, the presence of oxygen and the bed depth of adsorbent were the biggest variables to adsorptivity.