Absorption of nitric oxide in simulated flue gas by a metallic functional ionic liquid

Nitric oxide (NO) is one of the main air pollutants threatening human health and environment, but it is also an important intermediate for the production of nitric acid. In this work, a metallic functional ionic liquid (IL) [Bmim](2)FeCl4 was designed and applied to efficiently and reversibly absorb NO in a simulated flue gas. The effects of absorption time, temperature, and NO concentration on the absorption in the IL were investigated. The results indicated that the absorption capacity of NO by the IL increased as temperature decreased and NO concentration increased. The absorption capacity of NO with a concentration of 0.2% by the IL was high up to 0.205 mol NO per mol IL at 30 degrees C, and the absorbed NO could be desorbed from the IL at 80 degrees C. The regeneration experiments demonstrated that the IL could be reused, and its absorption capacity did not vary in four absorption/desorption cycles. The absorption mechanism of NO by the IL was studied by FT-IR, and the result indicated that there was a chemical interaction between Fe2+ and NO, and Fe2+ was the absorptive active species.