Synthesis and characterization of nano-sized Mn–TiO2 catalysts and their application to removal of gaseous elemental mercury

Abstract

To prepare suitable materials for capture of mercury from coal-fired flue gas, nano-sized Mn–TiO2 catalysts with different manganese loadings were synthesized by use of the template method. Catalytic oxidation performance in the removal of elemental mercury on these catalysts was tested over a wide range of temperature (150–350 °C). Powder X-ray diffraction, N2 adsorption, and transmission electron microscopy were used to characterize the catalysts. Results showed that Mn–TiO2 with 10 % manganese content could remove up to 95 % of elemental mercury (balanced with air) at rather high gas space velocity (1.5 × 105 h−1). It was found that SO2 inhibited removal of elemental mercury by the catalysts whereas NO had a promoting effect. HCl was also observed to slightly inhibit conversion of mercury on the catalysts. The manganese loading had an important effect on the catalytic oxidation of elemental mercury. With increasing manganese content, the performance of the catalysts in removal of elemental mercury improved. Mn–TiO2 (10 %) was up to 95 % efficient at removal of elemental mercury in the temperature range investigated.