Chemical Engineering Journal, Vol.292, 123-129, 2016
Enhancement of heterogeneous oxidation and adsorption of Hg-0 in a wide temperature window using SnO2 supported LaMnO3 perovskite oxide
LaMnO3/SnO2 composite was synthesized as a novel material for the catalytic oxidation and adsorption of elemental mercury (Hg-0). The results indicated that the catalyst having a LaMnO3:SnO2 = 1:1 M ratio exhibited the highest activity with higher than 99% Hg-0 removal efficiency. LaMnO3 was the primary active sites for Hg-0 catalytic oxidation and adsorption. SnO2 as catalyst support for LaMnO3 can enlarge the reaction temperature window. The mechanism for Hg-0 removal was discussed by means of XRD, Raman, BET, TEM, H-2-TPR and XPS analysis. The larger surface areas, the more oxygen vacancies and the higher oxidation performance were obtained when SnO2 acted as catalyst support for LaMnO3. At low temperature, Mn was the primary active sites for Hg-0 catalytic oxidation along with the adsorption by adsorbed-oxygen. With the temperature rising, SnO2 can adsorb O-2 to form O2- on its surface which was beneficial for the oxidized mercury adsorption. Moreover, SnO2 exhibited high activity for Hg-0 oxidation when the temperature was higher than 250 degrees C. The Hg-TPD results indicated that the mercury existed stronger binding state on the surface of LaMnO3/SnO2. (C) 2016 Elsevier B.V. All rights reserved.