Investigation of simultaneous adsorption of SO2 and NOx on Na-γ-alumina with transient techniques

The simultaneous adsorption of SO₂ and NO_x on Na-γ-alumina was studied by means of step experiments in a fixed bed plug flow reactor at 387 K and atmospheric pressure. Typically the molar composition of the feed gas was 1.5% SO₂, 1% O₂, 4000 ppm NO, 500 ppm NO₂, and Ar. First the adsorption behavior of the pure components was measured. SO₂ and NO₂ adsorb easily, whereas NO and O₂ do not adsorb. Moreover there is no influence of O₂ on the adsorption behavior of the pure components.

NO and O₂ adsorption require the simultaneous presence of SO₂, NO, and O₂. The NO and O₂ adsorption rate is enhanced by an increasing SO₂/NO ratio. The total amount of SO₂ adsorbed is not affected by the simultaneous adsorption of NO and O₂. However, NO₂ adsorption increases the SO₂ adsorption capacity. In the presence of NO₂ most of the adsorbed NO_x is released as NO.