Outstanding Resistance of H2S-Modified Cu/TiO2 to SO2 for Capturing Gaseous Hg0 from Nonferrous Metal Smelting Flue Gas: Performance and Reaction Mechanism

The utilization of H2SO4, produced using SO2 from nonferrous metal smelting flue gas as a source of S, is extremely restricted due to Hg contamination; therefore, there is great demand to remove He from smelting flue gas. Although the ability of Cu/TiO2 to capture He is excellent, its resistance to H2O and SO2 is very poor. In this study, Cu/TiO2 was treated with H2S to improve its resistance to H2O and SO2 for capturing He. The chemical adsorption of He on Cu/TiO2 was primarily through the HgO route, which was almost suppressed by H2O and SO2 due to the transformation of CuO into CuSO4. Besides the HgO route, the HgS route also contributed to the chemical adsorption of He on modified Cu/TiO2. As the CuS on modified Cu/TiO2 was inert to H2O and SO2, the chemical adsorption of He on modified Cu/TiO, through the HgS route was barely inhibited. Meanwhile, the HgS route was predominant in the chemical adsorption of He on modified Cu/TiO2. Therefore, modified Cu/TiO2 exhibited an excellent resistance to H2O and SO2, and its He capture capacity from simulated flue gas was up to 12.7 mg g(-1) at 100 degrees C.