Immobilization of elemental mercury in non-ferrous metal smelting gas using ZnSe_(1-x)S_x nanoparticles

摘要

Gaseous elemental mercury (Hg-0) in non-ferrous smelting gas is generally accompanied by a high concentration of SO2. Traditional sorbents for Hg-0 removal often suffer from SO2 poisoning. To develop a sorbent that has high mercury removal efficiency and excellent sulfur resistance, Zn-Se-S composites were selected. The experimental results indicated that the ZnSe0.7S0.3 composite had the best Hg-0 removal performance, achieving an Hg-0 removal efficiency higher than 99% after 120 min of reaction at 150 degrees C. A "hump" was observed in the adsorption breakthrough curve. This phenomenon is due to the activation of surface Se-0, with reduction in surface oxidation state (from Se2+ to Se-0) by Hg-0 or SO2. This composite has multiple adsorption sites (Se-0 and active S) for mercury uptake from smelting gas. Moreover, this specific Zn-Se-S composite had excellent SO2 resistance. Even high concentrations (1000 or 2000 ppm) of SO2 barely influenced Hg-0 removal performances. The Zn-Se-S composite exhibited potential for Hg-0 removal from non-ferrous smelting gas.