Mn-based perovskite oxides for Hg-0 adsorption and regeneration via a temperature swing adsorption (TSA) process

摘要

Mn-Based perovskite oxides combined with a temperature swing adsorption (TSA) process were employed for Hg-0 adsorption and regeneration from coal-fired flue gas, in which oxygen directly acted as oxidant to enhance the capture of Hg-0. Three kinds of Mn-based perovskie oxides, SrMnO3, LaMnO3 and CeMnO3 were evaluated. The results indicated that the performances for Hg-0 removal decreased in the order of LaMnO3 > CeMnO3 > SrMnO3. LaMnO3 had a Hg-0 capacity of 6.22 mg/g with 4% O-2 at 150 degrees C. O-2 significantly enhanced the reaction activity, the Hg-0 capacity was increased by approximately 6.5% in the presence of 8% O-2. The characterization results indicated that perovskite crystal structure was beneficial for Hg-0 capture. The Hg-0 removal mechanism was primary ascribed to catalytic oxidation and chemical-adsorption. The abundant of adsorbed oxygen, high ratio of Mn4+/Mn3+ in LaMnO3 lead to the high activity. Moreover, LaMnO3 can be regenerated without the loss of capacity. The released Hg-0 could be gathered which prevent from mercury secondary pollution in the environment. (C) 2016 Published by Elsevier Ltd.