Dispersion of Na2CO3 on γ-Al2O3 and the threshold effect in flue-gas desulfurization

Na2CO3 can disperse onto the surface of γ-Al2O3 and form a quite complete monolayer. The adsorption capacity of SO2 on Na2CO3/γ-Al2O3 increases with Na2CO3 loading, and reaches a maximum at the dispersion threshold. When the loading is below the threshold, the adsorption is in company with oxidation of SO2, and the regeneration recovery percentage of the adsorbent is beyond 60%. However, as the loading is at the threshold or higher, the adsorption is only an acidic–basic interaction and the regeneration recovery percentage is much lower. With due consideration for all concerned, the chosen Na2CO3 loading should enable Na2CO3 in the sample to cover the greater part, but not the whole surface of γ-Al2O3.