Design of 3D MnO/Carbon Sphere Composite for the Catalytic Oxidation and Adsorption of Elemental Mercury

Three-dimensional (3D) MnO/Carbon Sphere (MnO/CS) composite was synthesized from zero-dimensional carbon spheres and one-dimensional α-MnO using hydrothermal method. The hierarchical MnO/CS composite was applied for the catalytic oxidation and adsorption of elemental mercury (Hg) from coal-fired flue gas. The characterization results indicated that this composite exhibits a 3D urchin morphology. Carbon spheres act as the core and α-MnO nano-rods grew on the surface of carbon spheres. This 3D hierarchical structure benefits the enlargement of surface areas and pore volumes. Hg removal experimental results indicated that the MnO/CS composite has an outstanding Hg removal performance due to the higher catalytic oxidation and adsorption performance. MnO/CS composite had higher than 99% Hg removal efficiency even after 600min reaction. In addition, the nano-sized MnO/CS composite exhibited better SO resistance than pure α-MnO. Moreover, the Hg-TPD results indicated that the adsorbed mercury can release from the surface of MnO/CS using a thermal decomposition method.