Porous structure and effective active site are beneficial for gaseous elemental mercury (Hg0) capture. Two kinds of hierarchical porous layered double hydroxides (LDHs) were synthesized through an in-situ growth method.… Click to show full abstract
Porous structure and effective active site are beneficial for gaseous elemental mercury (Hg0) capture. Two kinds of hierarchical porous layered double hydroxides (LDHs) were synthesized through an in-situ growth method. Sulfur was used for the modification of these LDHs to enhance Hg0 removal performance. Two as-prepared NiAl-S4@SiO2 microspheres displayed three-dimensional morphologies, accordingly exhibited as core-shell and urchin-like morphologies. XRD, BET, FTIR, TEM and SEM were employed to investigate the structure effect on Hg0 uptake. The results indicated that after S-modification, the Hg0 removal efficiencies as well as SO2 resistance were enhanced. The Hg0 removal performances follow the order of: NiAl-S4@SiO2-urchin > NiAl-S4@SiO2-core at 100 °C. The mechanism for Hg0 removal was discussed based on the results of TPD, EDX and XPS. The porous structure of NiAl-S4@SiO2 composite was beneficial for gas transformation and intercalated [S4]2- ions were favorable for mercury uptake. The polysulfide combined with adsorbed mercury and formed HgS. Such materials exhibit promising potential for mercury uptake from SHg mixed flue gas.
               
Click one of the above tabs to view related content.