第二届中国化学链会议

The effects of Cu doping on the adsorption and oxidation of Hg⁰ were adopted by a small fluidized bed and DFT calculations. The results showed that compared with Fe₂O₃, Cu doping could convert more Hg⁰ into Hg²⁺ and Hg(P) for improving the capacity of oxygen carriers to reduce Hg⁰. XPS and Hg-TPD further verified HgO and HgS to be the main forms of Hg(P). DFT calculations revealed that Cu doping enhanced all the adsorption capacities of Hg⁰, H₂S, HgO and HgS. The Projected Density Of States(PDOS),the Brønsted−Evans−Polanyi (BEP) relationship and the d-band center theory implied that comparing with Fe₂O₃, Cu doping made the d-band center of Fe atoms closer to Fermi level, optimized the adsorption capacities of intermediates and transition-states on Fe-Sites, thus significantly reduced the energy barrier of the rate control step (Hg/O's Hg*+O*→HgO*;Hg/S' HS*→S*+H* and S*+Hg*→HgS*) which further accelerated the overall Hg/O and Hg/S reactions' kinetics. Therefore, Cu could be applied as a potential dopant to not only improve the capacity of oxygen carriers to adsorb and oxidize Hg⁰ but also optimize the emission reduction of this chemical.
 

Fe2O3; Density functional theory; Coal; Chemical looping gasification; Elemental mercury; Doping; Removal.