Cu-modified Fe-Mn magnetic mercury adsorbent and anti-SO2 characteristic

A series of Fe₆Mn₁Cu_x adsorbents for mercury removal were prepared by using co-precipitation and impregnation methods. The performance of mercury adsorption and anti-SO₂ characteristic was studied in a fixed-bed experimental system. The effect of Cu doping amount, reaction temperature, and flue gas components on mercury removal was investigated. The mercury species on the spent adsorbent was analyzed through Hg-TPD test. The physical–chemical features were characterized by using the N₂ adsorption/desorption, VSM, XPS, and XRD. It was found that the Fe₆Mn₁Cu_0.4 exhibited a high performance of mercury adsorption and well magnetic property and good sulfur resistance. Under high concentration of SO₂, the average adsorption efficiency of Fe₆Mn₁Cu_0.4 adsorbent achieved 99%. Cu modification optimized the pore structure and improved the mercury removal performance as well as SO₂ resistance. The XPS analysis indicated that Mn⁴⁺ was the main form that played an important role in oxidizing Hg⁰, as a result of decrement of Mn⁴⁺ after mercury adsorption. Mercury adsorbed on the spent adsorbent was HgO and HgSO₄.