The effect of water vapor on NOx storage and reduction in combination with plasma

In this study, the effect of water vapor on NOx storage and reduction in combination with non-thermal plasma was investigated. The results indicated that H2O could lower NOx adsorption capacity of H-ZSM-5 at the adsorption stage, due to the competitive adsorption between H2O and NOx on the surface of H-ZSM-5. When the content of H2O was above 2%, the NOx breakthrough adsorption capacity of H-ZSM-5 remained stable at 2.0 mL g−1. At the discharge stage, the introduction of H2O decreased the total NOx conversion from 98.7% to 94.2%, while the conversion of adsorbed NOx to N2 from 94.0% to 83.9%. When increasing the CH4 concentration and the discharge power, the total NOx conversion and the conversion of adsorbed NOx to N2 moved up to 99.5% and 97.4%, respectively. In addition, although Ni-ZSM-5 exhibited better resistance to H2O than H-ZSM-5 for NOx adsorption, it showed inferior efficiency for NOx removal and nearly 15% NOx remained after the discharge stage.