Combined effects of Ag and UiO-66 for removal of elemental mercury from flue gas.

The zirconium metal-organic framework material UiO-66 was doped with Ag nanoparticles and investigated for the removal of elemental mercury (Hg0 ) in flue gas. Physical and chemical characterization of the adsorbents showed that adding Ag did not change the crystal structure and morphology of the UiO-66. Ag doping can improve the redox activity of UiO-66, and the adsorbent exhibited high thermal stability and surface area. Hg0 removal experiments indicated that UiO-66 exhibited the higher performance compared with P25 and activated carbon, and the addition of Ag exhibited a significant synergistic effect with the UiO-66, which had highest Hg0 adsorption capacity (3.7 mg/g) at 50 °C. Furthermore, the Hg0 removal mechanism was investigated, revealing that Hg0 is removed by the formation of an Ag amalgam and channel adsorption at low temperature, and through Ag-activated oxygen oxidation and channel capture at high temperature.