Simultaneous Adsorption of Gaseous Hg 0 and Hg(II) by Regenerable Monolithic FeMoS x /TiO 2 : Mechanism and its Application in the Centralized Control of Hg Pollution in Coal-Fired Flue Gas.

FeMoS x /TiO 2 was investigated as a regenerable sorbent to simultaneously adsorb Hg 0 and Hg(II) from coal-fired flue gas for the centralized control of Hg pollution discharged from coal-fired power plants. The performance of FeMoS x /TiO 2 for Hg(II) and/or Hg 0 adsorption was evaluated on a fixed-bed reactor at 80 o C, and the mutual interference between Hg 0 adsorption and Hg(II) adsorption was analyzed using individual adsorption, simultaneous adsorption, and two-stage adsorption. FeMoS x /TiO 2 displayed an excellent capacity for individual Hg 0 adsorption (41.8 mg g -1 ) and a moderate capacity for individual Hg(II) adsorption (0.48 mg g -1 ). Two types of adsorption sites were present on FeMoS x /TiO 2 for gaseous Hg adsorption (S 0 and FeS 2 /MoS 3 sites). X-ray photoelectron spectroscope and kinetic analyses demonstrated that Hg 0 and Hg(II) could adsorb onto S 0 sites, whereas only Hg 0 was adsorbed onto FeS 2 /MoS 3 sites. As Hg 0 competed with Hg(II) for the S 0 sites, the amount of Hg(II) adsorbed slightly decreased by 16% in the presence of Hg 0 . However, Hg 0 adsorption onto the FeS 2 /MoS 3 sites predominated over the Hg 0 adsorption onto FeMoS x /TiO 2 and it was not inhibited in the presence of Hg(II). Therefore, the amount of Hg 0 adsorbed on FeMoS x /TiO 2 was only decreased by 2% in the presence of Hg(II).