Excellent adsorption performance and capacity of modified layered ITQ-2 zeolites for elemental mercury removal and recycling from flue gas

Adsorption is a superior method for removing and recycling high concentration of mercury from nonferrous metal smelting flue gas, especially adsorbents with good sulfur resistance and large adsorption capacity. In this study, Co and Mn oxide-modified layered ITQ-2 zeolites were designed to capture and recycle elemental mercury (Hg-0). The physicochemical characteristics of the adsorbents were characterized using BET, XRD, FESEM, TEM, and XPS, and the results showed that Mn/ITQ-2 zeolite has a large specific surface area, and MnOx was highly dispersed on ITQ-2 zeolite. The Hg-0 removal efficiency and adsorption capacity of the 5%Mn/ITQ-2 zeolite at 300 degrees C were 97% and 2.04 mg/g in 600 min, respectively, much higher than those of the previously reported 5% Mn/MCM-22 zeolite. The 2%Co-2%Mn/ITQ-2 zeolite exhibited a higher SO2 resistance performance. The mechanism of Hg-0 removal was concluded to be driven by the primary catalytic oxidation of MnOx secondary oxidation of active chlorine, and concurrent chemisorption. However, the Hg-0 adsorption capacity was determined by the specific surface area and pore structure of ITQ-2. The 2%Co-2%Mn/ITQ-2 zeolite exhibited a high SO2 resistance performance. The Mn/ITQ-2 and Co-Mn/ITQ-2 zeolites have excellent regenerability and reusability, which can realize mercury recycling from flue gas.

Automated summary

Adsorption is an effective method for removing and recycling high concentration of mercury from nonferrous metal smelting flue gas, especially with adsorbents like Mn/ITQ-2 zeolite which have large specific surface area and good Hg-0 removal efficiency. The study also found that Co-Mn/ITQ-2 zeolites exhibit high SO2 resistance performance and excellent regenerability, making them a promising option for mercury recycling from flue gas.