Safe disposal of deactivated commercial selective catalytic reduction catalyst (V_2O_5-MoO_3/TiO_2) as a low-cost and regenerable sorbent to recover gaseous elemental mercury in smelting flue gas

摘要

The reduction of Hg emissions from non-ferrous metal smelting was proposed in the Minamata Convention. Regenerable sulfureted MoO3/TiO2, which displayed excellent performance in capturing gaseous Hg-0, was once developed by us to recover gaseous Hg-0 in smelting flue gas (SFG) for centralized control. Recently, a large amount of spent commercial selective catalytic reduction catalysts (for example V2O5-MoO3/TiO2) mostly deactivated by CaSO4 was formed, creating a need for their safe disposal. As the main constituent of deactivated V2O5-MoO3/TiO2 is MoO3/TiO2, deactivated V2O5-MoO3/TiO2 was sulfureted to capture gaseous Hg-0 from SFG for its safe disposal and the effects of V2O5 and CaSO4 on Hg-0 adsorption onto sulfureted MoO3/TiO2 were investigated. Although the capturing capacity of sulfureted MoO3/TiO2 moderately decreased after the impregnation of V2O5 and CaSO4, sulfureted deactivated V2O5-MoO3/TiO2 still displayed excellent performance and reproducibility in gaseous Hg-0 capture. Meanwhile, the cost performance of sulfureted deactivated V2O5-MoO3/TiO2 for Hg-0 capture was outstanding as deactivated V2O5-MoO3/TiO2 needs to be safely disposed. Therefore, deactivated V2O5-MoO3/TiO2 can be sulfureted as a regenerable and low-cost sorbent that is effective in recovering gaseous Hg-0 from SFG, as well as being a cost-effective and environmentally friendly method for the safe disposal of spent V2O5-MoO3/TiO2 for Hg-0.