Treatment of NO by a combination of MnO2 and a CO32−-intercalated Mg–Al layered double hydroxide

Abstract

We examined the treatment of NO from simulated exhaust gas using a combination of MnO2 and a CO32−-intercalated Mg–Al layered double hydroxide (CO3·Mg–Al LDH), and found that low removal efficiencies were obtained when CO3·Mg–Al LDH was used in the absence of MnO2. The exhaust gas was circulated in a reaction tube filled with MnO2 (first step) and CO3·Mg–Al LDH (second step), and the NOx removal efficiency of ~ 70% achieved at 170 °C at the beginning of the reaction decreased to 60% after 90 min. Compared to the case of only CO3·Mg–Al LDH, the NOx removal efficiency significantly increased when both MnO2 and CO3·Mg–Al LDH were employed, which was ascribed to the oxidation of NO to NO2 over MnO2 followed by the subsequent removal of NO2 by CO3·Mg–Al LDH.