Highly effective and energy-saving removal of NO through an adsorption–microwave catalytic decomposition method under complex flue gas at low temperature

Abstract

Low-temperature NO decomposition with high efficiency and low energy consumption remains a huge challenge. Herein, we reported a novel adsorption–microwave catalytic decomposition method for the deep removal of NO using NaY-MgCo₂O₄-40%BaCO₃ as the bi-functional adsorbent/catalyst material under complex flue gas. At room temperature, under the condition of excess O₂, NO was first adsorbed on the bi-functional material for concentration, and then the adsorbed NO was quickly decomposed into N₂ and O₂ by microwave (MW) catalysis at a low temperature of 250 °C. It was found that the conversion of adsorbed NO reached 99.5% after only 15 min of microwave irradiation. NaY-MgCo₂O₄-40%BaCO₃ had excellent recyclability with a high NO removal rate of 98.2% in the 4-cycles’ operation. Moreover, the application of the adsorption–microwave catalytic decomposition method for denitrification under complex flue gas (the presence of SO₂ or CO₂) was studied for the first time, and NaY-MgCo₂O₄-40%BaCO₃ showed superior resistance to SO₂ and CO₂. This work provides a new and attractive approach for the deep removal of NO_x at low temperature without adding an additional reducing agent, and it is green, efficient and energy-saving.