Remarkable improvement of Ti incorporation on Hg0 capture from smelting flue gas by sulfurated γ-Fe2O3: Performance and mechanism

Except for the dangerous Boliden-Norzink technology, recovering gaseous Hg-0 as liquid Hg-0 using recyclable sorbents was an achievable method to control Hg-0 emissions from smelting flue gas. In this study, Ti was incorporated into sulfurated gamma-Fe2O3 to improve its performance for capturing Hg-0 from smelting flue gas, and the mechanism of Ti incorporation on Hg-0 adsorption onto sulfurated gamma-Fe2O3 was investigated by comparing the kinetic parameters. The kinetic analysis showed that the Hg-0 adsorption rate primarily depended on the amounts of surface adsorption sites for the physical adsorption of Hg-0 and surface S-2(2-) for Hg-0 oxidation. Since the amounts of both adsorption sites and S-2(2-) on sulfurated gamma-Fe2O3 increased remarkably after Ti incorporation, Hg-0 adsorption onto sulfurated gamma-Fe2O3 was notably improved by 190-350%. The capacity of sulfurated Fe-Ti spinel for Hg-0 capture could reach 48.6 mg g(-1) and its average adsorption rate could reach 43.3 mu g g(-1) min(-1) in 3 h. Meanwhile, the used sulfurated Fe-Ti spinel could be easily regenerated without any apparent degradation. Thus, sulfurated Fe-Ti spinel offered a significant advantage in recovering Hg from smelting flue gas.