Mercury removal over Ce-doped LaCoO3 supported on CeO2 at low temperatures from coal combustion flue gas

Mercury has a significant impact on environment and is mainly derived from coal-fired power plant. Herein, we report a potential route for efficient removal of Hg0 via oxidation reactions using Ce-doped LaCoO3 supported on CeO2 catalyst. Catalyst characterization results proved that Ce can successfully substitute a desired part of Co into the LaCoO3 crystal lattice via a sol-gel method. The Hg0 removal experiments suggest that Hg0 removal effi-ciency decreased in the order of La0.875Ce0.125CoO3/CeO2 > La0.875Ce0.125CoO3 > LaCoO3. The presence of O2 provided more active oxygen and resulted in approaching 100% Hg0 removal efficiency. Introducing H2O and sole SO2 would significantly reduce the Hg0 removal efficiency as a result of competitive adsorption on the actives sites of the catalyst. On the other hand, SO2 could reacted with Hg0 in the presence of O2 and thereby recover the high Hg0 removal efficiency and the La0.875Ce0.125CoO3/CeO2 catalyst presented a good performance towards sulfur resistance. Furthermore, the catalyst still exhibited a high Hg0 removal efficiency performance after five times consecutive recycles.

Automated summary

Mercury, mainly derived from coal-fired power plants, has a significant impact on the environment. In this study, we propose a potential method for efficient removal of Hg0 through oxidation reactions using Ce-doped LaCoO3 supported on CeO2 catalyst. The catalyst characterization results confirm the successful substitution of Co with Ce in the LaCoO3 crystal lattice. The Hg0 removal experiments demonstrate that the La0.875Ce0.125CoO3/CeO2 catalyst exhibits the highest removal efficiency, and the presence of O2 greatly enhances its effectiveness. The addition of H2O and SO2 reduces the Hg0 removal efficiency due to competitive adsorption, but the presence of O2 allows SO2 to react with Hg0 and recover the efficiency.