Adsorption and desorption of SO2, NO and chlorobenzene on activated carbon

Activated carbon(AC) is very effective for multi-pollutant removal; however, the complicated components in flue gas can influence each other’s adsorption. A series of adsorption experiments for multicomponents, including SO, NO, chlorobenzene and H2 O,on AC were performed in a fixed-bed reactor. For single-component adsorption, the adsorption amount for chlorobenzene was larger than for SOand NO on the AC. In the multi-component atmosphere, the adsorption amount decreased by 27.6% for chlorobenzene and decreased by 95.6% for NO, whereas it increased by a factor of two for SO,demonstrating that a complex atmosphere is unfavorable for chlorobenzene adsorption and inhibits NO adsorption. In contrast, it is very beneficial for SOadsorption. The temperature-programmed desorption(TPD) results indicated that the binding strength between the gas adsorbates and the AC follows the order of SO> chlorobenzene > NO. The adsorption amount is independent of the binding strength. The presence of H2 O enhanced the component effects, while it weakened the binding force between the gas adsorbates and the AC. AC oxygen functional groups were analyzed using TPD and X-ray photoelectron spectroscopy(XPS) measurements. The results reveal the reason why the chlorobenzene adsorption is less affected by the presence of other components. Lactone groups partly transform into carbonyl and quinone groups after chlorobenzene desorption. The chlorobenzene adsorption increases the number of C = O groups, which explains the positive effect of chlorobenzene on SOadsorption and the strong NO adsorption.