Study of dynamics and mechanism of HCl, SO2, or NO removal by MnO2/Mg–Al layered double hydroxide.

[Display omitted] • MnO 2 /Mg–Al LDH is able to remove both HCl and SO 2 gases in addition to NO. • The HCl removal proceeds mainly through the reaction of HCl with the CO 3 2− and OH− in the LDH layers. • The SO 2 removal takes place through the adsorption of SO 2 onto the LDH and MnO 2 surfaces. • The NO removal occurs through the oxidation of NO to NO 2 by MnO 2. • It follows by the reaction of NO 2 with the CO 3 2− and OH− in the LDH layers. The gas exhaust generated by waste incinerators contains toxic acid gases such as HCl, SO 2 , and NO x , which require appropriate treatment following their release. Although several methods exist for this purpose, they have various drawbacks. Thus, toward the search for a new removal method, the ability of Mg–Al layered double hydroxide (Mg–Al LDH) to eliminate HCl, SO 2 , and NO gases from simulated exhaust gas was examined. In addition, the impact of the amount of LDH employed was investigated in terms of the toxic gas removal efficiencies and process temperature. Furthermore, the mechanism of removing HCl, SO 2 , and NO by MnO 2 /Mg–Al LDH was considered. More specifically, HCl removal proceeded mainly by the reaction of HCl with the CO 3 2− and OH− species present between the Mg-Al LDH layers, while that of SO 2 took place through the adsorption of SO 2 onto the LDH and MnO 2 surfaces. Moreover, NO was removed through the oxidation of NO to NO 2 by MnO 2 , followed by the reaction of NO 2 with the CO 3 2− and OH− species present between the Mg–Al LDH layers. These results are expected to help pave the way for the use of Mg–Al LDH to remove toxic acid gases from the gas exhausts of waste incinerators, thereby addressing the various issues related to the use of current technologies. [ABSTRACT FROM AUTHOR]