Vanadium silicate (EVS)-supported silver nanoparticles: A novel catalytic sorbent for elemental mercury removal from flue gas.

• Ag modified EVS was synthesized and used as catalytic sorbent for Hg° capture. • The doped Ag nanoparticles can significantly improve Hg° oxidation efficiency. • The interaction between Ag and V was responsible for the low temperature activity. • The role of silver and vanadium on the Hg° oxidation process was discussed. Vanadium silicate (EVS) is a vanadium-substituted form of titanosilicate that has a high potential for use as a sorbent for mercury removal. In the present study, EVS with supported silver nanoparticles (EVS-Ag100) as the catalytic sorbent was synthesized for elemental mercury (Hg°) capture. The physical and chemical properties of the sorbents were investigated. The raw EVS exhibited a poor Hg° capture capacity (7.7 μg g−1), because most of the vanadium species in the structure of EVS were V4+. The loading of the silver could significantly enhance the Hg° capture capacity (63.4 μg g−1). EVS-Ag100 exhibited a superior Hg° capture performance at temperatures of approximately 150 °C. Silver nanoparticles that formed on the EVS were the active sites. In addition, the vanadium species of EVS-Ag100 exhibited higher Hg° oxidation activity than those in the framework of raw EVS. The XPS results revealed the activation of the vanadium species by the silver nanoparticles. After the capture of Hg° in the presence of O 2 , more V5+ was observed on the surface of EVS-Ag100. Exposure of EVS-Ag100 to a continuous simulated flue gas at 150 °C with a gas hourly space velocity of 220,000 h−1 led to Hg° removal efficiency of >96% in a 1 h test. [ABSTRACT FROM AUTHOR]